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P1:JDT PB336B-37 Feldhammer/0180G July21,2003 17:14 37 Mountain Lion BeckyM.Pierce Pumaconcolor VernonC.Bleich NOMENCLATURE among mountain lions throughout their range. Although the degree ofsexualdimorphismdidnotvarygeographically,thesizeofmoun- CN.Mountainlion,puma,panther,catamount,andcougar tainlionsgenerallyincreasedwithanincreaseinlatitude(Kurten1973; SN.Pumaconcolor Iriarteetal.1990). Thedorsalpelageofamountainlionistawny,andtheygenerally TAXONOMY arewhiteontheventralsurface(Fig.37.1).Slightvariationincoloris common,andtheircoatscanhavereddish,yellowish,orgrayishtinges. Mountainlionshaveacomplicatedtaxonomichistory.Numeroussub- Therearenoobviouscontrastingmarkingsonthecoatsofadultlions, species have been described, largely based on morphometric differ- otherthanblackmarkingsatthebaseofthevibrissaeonthemuzzle, ences. For example, Young and Goldman (1946) listed a total of 30 onthedorsalsurfaceoftheears,andonthetipofthetail.InLatin,the subspecies,andCulveretal.(2000)notedthat32namedsubspecies specificepithetconcolormeans“singlecolor.” existed. Of those listed by Young and Goldman (1946), at least 13 In contrast to adults, young mountain lions have darker facial occurred in Canada or the United States (and adjacent Mexico); the markingsandareheavilyspottedatbirth(Fig.37.2),butthatpattern remainderhadgeographicdistributionsrestrictedtoMexico,Central fadesaskittensmature.Thespottedpelageofkittensbecomeslessob- America,orSouthAmerica. viousatabout9monthsofage.Bythetimeyoungareapproximately Themountainlionwasfirstdescribedfromaspecimencollected 2yearsold,thespottinghaslargelydisappeared(Russell1978).The inBrazil(Marcgrave1648);Linnaeusreclassifiedthemountainlionas eyesareclosedatbirth,butopenby2weeksofage(YoungandGoldman Felisconcolorin1771.Jardine(1834)placedthespeciesinthegenus 1946).LoganandSweanor(1999)reportedthatthelightblueeyecolor Puma,whereitremains(Wozencraft1993).Thehistoricaltaxonomy ofkittenschangestotheambercolortypicalofadultswhenkittensare of the mountain lion was reviewed in detail by Young and Goldman asyoungas5months. (1946)andCurrier(1983). Despitethelargedifferenceinbodyweighttypicalofadultmales Basedonmolecularandmorphologicalinvestigations,themoun- andfemales,distinguishingthesexesfromadistancecanbedifficult. tainlionisthoughttohaveevolvedfromanancestorincommonwiththe Unlessmalesareinanolderagecategory,withwell-developedshoul- cheetah(Acinonyxjubatus)andjaguarundi(Herpailurusyaguaroundi) der,neck,andfacialmusculature,bodyconformationofyoungadult (Van Valkenburgh et al. 1990; Janczewski et al. 1995; Johnson and malescanbeconfusedwiththatofolderadultfemales.Genderscan O’Brien1997;Pecon-SlatteryandO’Brien1998).Mountainlionsare bedistinguishedbyobservingthegenitalia,butmalelionsfrequently representedintheNorthAmericanfossilrecorddatingback300,000 are misclassified as females, even by professional wildlife biologists years(Turner1997).Basedonanextensiveanalysisofmitochondrial andlawenforcementpersonnel,becausethescrotumandpenisarenot DNA haplotypes and microsatellite alleles from throughout the geo- obvioustotheuntrainedobserver.Darkcolorationisassociatedwith graphicrangeofPumaconcolor,Culveretal.(2000)speculatedthata hairsurroundingthepenissheathofmales,andisanimportantclueto massextinctionduringthePleistocene(Martin1989),whicheliminated thegenderoflions(LoganandSweanor1999). themajorityoflargemammalsinNorthAmerica,wasfollowedbya colonizationofmountainlionsofSouthAmericanstock.Furthermore, Culveretal.(2000)concludedthatmountainlions(northofNicaragua) todayrepresentasinglesubspecies,Pumaconcolorcouguar,inlieuof the15thatformerlywererecognized.FiveothersubspeciesofPuma concolorarerecognizedthroughouttheirsouthernrange(Culveretal. 2000). DESCRIPTION Althoughthesexesaresimilarinappearance,maleandfemalemountain lionsaredimorphicinsize.GayandBest(1995)examinedspecimens fromthroughouttherangeofmountainlionsandreportedthatmales weresignificantlylargerthanfemalesin14cranialand5mandibular measurements.InCalifornia,meanbodyweightofadult(≥2yearsof age)maleswasX¯=53.4kg(±8.5kg[SD]).Adultfemalesweighed30– 40%less(X¯=35.8±7.7kg)(Charltonetal.1998).Basedonasample of1076specimensfromOregon,KohlmannandGreen(1999)reported thatmalesaveragedabout50%heavierthanfemalesofequivalentage. GayandBest(1995)foundnoevidencethatsexualdimorphismamong mountain lions varied geographically. Data compiled by Anderson F37.1. Adultmountainlion(Pumaconcolor).S:PhotobyBecky (1983) show that similar degrees of sexual size dimorphism occur M.Pierce. 744 P1:JDT PB336B-37 Feldhammer/0180G July21,2003 17:14 MOUNTAINLION(Pumaconcolor) 745 F37.2. Threeweekoldmountainlion(Pumaconcolor).Kittensinthe birthnursery.S:PhotobyBeckyM.Pierce. Aswithallfelids,exceptcheetahs,mountainlionshaveretractable claws(Fig.37.3)attheterminusofeachdigit.Theseclawsfunction primarily to grasp prey, rather than as an aid in locomotion (Dixon 1982).Therostrumoffelidsisshortandtheorbitsarelarge(Fig.37.4) comparedtothoseofcanids.Theseskulladaptationsallowforamore powerfulbite,andfelidsaremoredependentonsightthanarecanids todetectprey(Vaughanetal.2000).TheadultdentalformulaisI3/3, C1/1,P3/2,M1/1. DISTRIBUTION Althoughtheyoccuratlowdensities,mountainlionsarethemostabun- dantlargefelidoccupyingNorthAmericaandaresecondinsizeonly tothejaguar(Felisonca)(Russell1978).Historically,mountainlion distributionencompassedmostofthewesternhemisphere(Youngand Goldman1946).TheyoccurredfromtheAtlantictothePacificoceans andfromapproximately50◦Nto50◦Slatitude,andfromnearsealevel to about 4000 m elevation (Young and Goldman 1946). In essence, mountainlionsrangedfromapproximatelytheCassiarRangeofnorth- ernBritishColumbiatosouthernChileandArgentina,andfromocean tooceanonthecontinentsofNorthandSouthAmerica. In North America, the distribution of mountain lions has been reduced by as much as two thirds of its historical range (Fig. 37.5), largelybecauseofconflictswithhumansassettlersmigratedwestward (Rossetal.1997).Currently,mountainlionsoccurinsuitablehabitat throughoutMexico,inthemajorityofthewesternUnitedStates,and inwesternCanada;asmallpopulationalsooccursinsouthernFlorida 2 cm F37.3. Retractileclawmechanismofthemountainlion(Puma F37.4. Skullofthemountainlion(Pumaconcolor).Fromtoptobottom: concolor).A,Extensorexpansion;B,middleinterphalangealjoint;C,extensor lateralviewofcranium,lateralviewofmandible,dorsalviewofcranium, tendon;D,flexordigitorumprofundustendon;E,lateraldorsalelastic ventralviewofcranium,dorsalviewofmandible. ligament;F,distalinterphalangealjoint.S:AdaptedfromGonyeaand Ashworth(1975). P1:JDT PB336B-37 Feldhammer/0180G July21,2003 17:14 746 CARNIVORES Florida panthers compared to a nearby “population,” and speculated Kilometers thatdifferencescouldbearesultofgeneralizeddifferencesinhealth 0 400 800 andnutritionalstatusbetweenthetwogroups.Itmayproveusefulfor Miles mountain lion researchers to examine hematological and serological 0 400 800 data from their study animals, given differences reported within lo- calizedareasaswellasamongwidelyseparatedpopulations(Dunbar etal.1997).Forexample,mountainlionsthatusehigh-elevationpasses tofollowmigratoryprey(Pierceetal.1999b)mayexhibitdifferences thatarenotevidentinmountainlionsfromthesamepopulation(s)that donotusehigh-elevationhabitats.Further,dataonhematologicaland serologicalparametersmayreflectthegeneralhealthstatusofmoun- tainlionsexistingunderdifferentnutritionalregimes(e.g.,abundantvs. uncommonprimaryprey)thatmayoccuraslionpopulationsfluctuate withpopulationsofmuledeer(Odocoileushemionus). Mountainlions,likemostcats,arewelladaptedtoapproaching preycloselyandthenrushingforwardquicklytosubduetheirintended target (Guggisberg 1975). As such, they are not adapted to running longdistances.Harlowetal.(1992)investigatedtheeffectsofpursuit onmountainlions.Animalsrespondedphysiologicallytostressesexpe- riencedduringpursuitbyadepressioninadrenalresponsiveness.They suggestedthatfrequentpursuitcouldresultindeleteriousphysiologi- calchangesandurgedcautionbywildlifeagenciesinsettingpursuit seasonsuntilmoreinformationbecomesavailable. BEHAVIOR Activity Patterns. Most felids are nocturnal predators (Kitchener 1991),andmountainlionsaremostactiveduringcrepuscularperiods Historical distribution (Ackerman1982;Hopkins1989;Sweanor1990).Thatpatternappears toshifttoamorenocturnalpatternformountainlionsintheproxim- Present distribution ityofhumandisturbance(VanDykeetal.1986).Mountainlionswill T37.1. Bloodserumbiochemicalvaluesforfree-ranging F37.5. Pastandpresentdistributionofthemountainlion(Puma mountainlionsfromCalifornia(n=19)andFlorida(88≤n≤94) concolor). Location(X¯±SD) (Fig.37.5).Recently,mountainlionshavebeenobservedinsoutheast- ernAlaskaandsouthwesternMinnesota(NowellandJackson1996), Parameter Units California Florida and they inhabit western North Dakota (Jensen 2001) and Nebraska (GenowaysandFreeman1996)andarethoughttobecolonizingprevi- Albumin g/dl 3.13a±0.32b 3.70±0.36 Alanineaminotransferase IU/L 58.8±16.7 60.2±35.0 ouslyoccupiedhabitatinOklahoma(Pikeetal.1997).Recentevidence Alkalinephosphatase IU/L 22.6±11.3 35.4±38.6 ofamountainlioninNewBrunswick,Canada,wasindisputable,butit Aspartateaminotransferase IU/L — 73.4±77.8 couldnotbeascertainedwhethertheanimalhadescapedfromcaptivity Calcium mg/dl 9.53±0.66 9.92±0.66 (CumberlandandDempsey1994).Thepersistenceofmountainlionsin Carbondioxide mEq/L 12.53±1.75 14.33±4.00 themaritimeregionsofCanadaandtheUnitedStatesremainsspecula- Cholesterol mg/dl 155.1±29.9 147.9±26.7 tive(Hansen1992).Anderson(1983)providedadetailedcompilation Chloride mEq/L — 115.5±4.3 of distributional records for mountain lions in the United States and Creatinephosphokinase IU/L — 515.6±415.1 Canada. Creatinine mg/dl 2.05±0.45 1.84±0.54 Gammaglutaminetransferase IU/L — 1.6±1.4 Globulin g/dl 3.45±0.41 — Glucose mg/dl 110.6±37.3 154.4±51.0 PHYSIOLOGY Inorganicphosphorus mg/dl 5.66±1.15 5.77±1.51 Therehasbeenapaucityofinformationonbloodparametersforfree- Iron µg/dl — 65.1±33.5 rangingmountainlions.Andersonetal.(1992)soughttorectifythisby Lactatedehydrogenase IU/L — 269.7±173.2 providinghematologicalandbiochemicalreferencevaluesfor≤7adult Potassium mEq/L — 4.60±0.48 Sodium mEq/L — 152.6±3.4 mountainlionsfromColorado.Priortothat,informationwaslimited Totalbilirubin mg/dl 0.30±0.25 0.26±0.61 toreportsbyCurrierandRussell(1982)orHawkeyandHart(1986). Totalprotein g/dl 6.58±0.67 7.35±0.67 Paul-Murphyetal.(1994)providedserumbiochemicalreferenceranges Triglycerides mg/dl — 54.9±103.4 for 19 free-ranging mountain lions from throughout California, and Ureanitrogen mg/dl 32.9±6.4 37.7±14.1 concludedthatthevaluesweresimilartothoseindomesticcatsand Uricacid mg/dl — 0.55±0.59 captiveexoticfelids.Dunbaretal.(1997)describedhematologicaland serumbiochemicalvaluesformountainlionsfromFlorida.Mostvalues S:DatahavebeenadaptedfromPaul-Murphyetal.(1994)andare wereconsistentwiththoseestablishedformountainlionsinColorado reporteddirectlyfromDunbaretal.(1997). aThenumberofdigitstotherightofthedecimalpointhasbeenreduced, (CurrierandRussell1982)andCalifornia(Paul-Murphyetal.1994), byrounding,forconsistencywiththedatareportedbyDunbaretal.(1997)for butsomedifferenceswereapparent(Table37.1). mountainlionsfromFlorida. Dunbaretal.(1997)attributedhigherpackedcellvolume,hemo- bPaul-Murphyetal.(1994)reportedmeansandtwostandarddeviationsfor globin,andredbloodcellvaluesreportedbyCurrierandRussell(1982) serumbiochemistryvalues.Standarddeviationsreportedherewerecalculated tothehigherelevationsinColoradothaninFlorida.Theyalsoreported byhalving,androundingasappropriate,datafromPaul-Murphyetal.(1994) higher values for these three parameters within one “population” of formountainlionsfromCalifornia. P1:JDT PB336B-37 Feldhammer/0180G July21,2003 17:14 MOUNTAINLION(Pumaconcolor) 747 repeatedly move and wait in ambush during the night when hunting houndsforresearchdoesnotappeartocausechangesinhomerangeuse (Beieretal.1995),butthatbehaviorissuspendedwhencachedprey orabandonmentofpreycachesinmostinstances(Seidenstickeretal. isavailable(Beieretal.1995;Pierceetal.1998).Movementtoprey 1973;Maehr1997;Pierceetal.1998,1999b).Mountainlionsremain caches at night occurs earlier for females with small young than for closetohumanactivitydirectlyafterbeingpursued,captured,andthen othersocialcategoriesofmountainlions(Pierceetal.1998).Thatbe- releasedforresearchpurposes(Seidenstickeretal.1973;Beieretal. haviorcouldbeastrategytoavoidadultmales,aresponsetogreater 1995).However,theyalsomayavoidareaswheretheyarerepeatedly energeticneedsofthemother,oratendencytokillpreyclosertothe harassed(HebertandLay1997;JanisandClark2002). daytimerestinglocationoftheyoung.Femalemountainlionswithout Mountainlionsmovequietlyandlowtothegroundwhenhunt- youngcovermoreareaandmakelongermovementsthanfemaleswith ingandstalkingprey(Koford1946;Wilson1984;BankandFranklin young(Sweanor1990).Malesmakethelongestmovements(Sweanor 1998).Earsalsomaybeloweredtoreducedetectionwhiletheymove 1990; Beier et al. 1995), cover the greatest area (Seidensticker et al. slowlyanddeliberately,frequentlyfreezinginpositionwhilewaiting 1973;Loganetal.1986a;Pierceetal.1998),andaremorelikelyto toapproachcloselyenoughtoambushtheintendedprey(Leyhausen leaveapreycachebeforeitiscompletelyconsumed(Ross1994).The 1979). When prey is within a suitable distance, they rush at the tar- moreextensivemovementsofmaleslikelyarenecessarytomonitoras get.Pursuitofpreybymountainlionsisrelativelyshortcomparedto manyfemalesaspossibleandresultinlargehomeranges. thelongchasesofcoursingpredators,suchaswolves(Canislupus).If Adult mountain lions spend a majority of time resting during a preyiscaught,itusuallyisattackedatorneartheneck.Whenattack- diel cycle (Beier et al. 1995). The long periods of rest exhibited by ingungulates,mountainlionsmostfrequentlygriptheanteriorventral mostfelidsmayreduceenergyexpenditureforaspeciesthatoftenkills portionoftheneck,deliveringacrushingbitetothetracheaandcaus- prey as large as or larger than itself and frequently has prey caches ingsuffocation(Kitchener1991).Thedorsalportionoftheneckalso available.Mountainlionswillgorgewhenalargeamountoffoodis maybebitten,andthespinalcordcanbesevered.Afterkillingprey, available(DanvirandLindzey1981;Ross1994)andmovemorefre- it is usual for mountain lions to open the body cavity of the carcass quentlywhentheyareunsuccessfulatmakingakill(Beieretal.1995). andremovethedigestivetract(Hornocker1970).Otherinternalorgans Mountainlionsalsoinhabitregionsofextremetemperatures:resting includingtheheart,liver,andlungsoftenareconsumedfirst(Danvir maybethemostefficientwaytopreventoverheatingindesertenviron- andLindzey1981).Gorgingonthemostnutritioustissuesduringthe mentsorconservingfatstoresinextremelycoldclimates.Thenegative firstdaymaybeanimportantstrategyformountainlionsthatcanlose relationshipbetweenmass-specificmetabolicrateandbodysizelikely foodtoscavengers(DanvirandLindzey1981)orneedtomovetolocate influencesthebehaviorpatternsoflargecarnivores(Robbins1993)and mates(Ross1994). accountsforlongperiodsofinactivitybymountainlions. Inanexaminationofhunter-killedmountainlions,Robinetteetal. (1959)reportedthat30%hademptystomachs.Mountainlionsmaycon- Communication. Mountain lions are the largest felid that make the sume>10kgofmeatduringasinglefeeding(Hornocker1970;Danvir low rumbling noise called a “purr.” Purring, chirping, and whistling andLindzey1981;Ackermanetal.1986),withmorebeingconsumed vocalizationshavebeendescribedforadultfemaleswhentheyreturn duringthefirstdaythanonconsecutivedaysfollowingthekill(Danvir totheiroffspring(Loganetal.1996).Defensivenessandaggressionare and Lindzey 1981). Results of field sampling and trials with captive expressedbyasuiteofsimilarbehaviorssharedamongfelids(Kitchener animalssuggestthatmountainlionsconsumeanaverageof4.4kgof 1991):earslayeddowninaflattenedposition,growling,openingthe meat/day(DanvirandLindzey1981;Ackermanetal.1986).Inmost mouth wide while making a hissing sound, tail twitching, and pilo- instances,preycarcassesaredragged,sometimes>200m,tolocations erection.Femalemountainlionsinestrusmakealoud“caterwauling” withvegetativeortopographiccover(Beieretal.1995).Whenlions vocalizationtoadvertisetheirconditiontomales,andthisbehaviorcon- finishfeeding,theyusuallyconcealthepreybycoveringitwithsticks, tinuesthroughoutanyresultingmatingassociation(Rabb1959;Padley grass,andothermaterialuntilthecarcassisconsumedorabandoned. 1991;Beieretal.1995;Loganetal.1996). Mountainlionsnormallyconsume73–79%ofadeercarcass(Danvir Homerangeareasofmountainlionsaremarkedbyscrapesmade andLindzey1981;Ackerman1982).Coveringcachesmayslowdecom- bypawingthegroundinabackwardmotion,drawingdirtandground positionofthemeatandhideitfromscavengers(Beieretal.1995).Prey litterintoasmallpilebehindtwoparallelgrooves(Seidenstickeretal. cachesmaybeguardedtoprotectthemfromscavengers,butmountain 1973).Malesmakescrapesmorefrequentlythanfemales(Cunningham lionscanuseday-bedsseveralkilometersfromkillsites,returningonly etal.1995),andscrapesoftenhavefecesorurinedepositsassociated atnighttofeed(Beieretal.1995;Pierceetal.1998,2000b). with them (Smith 1981; Logan et al. 1996). Scrapes occur most fre- quentlyinlocationswheretopographyfunnelsanumberofmountain lionsintothesamearea(Smith1981)andmayfacilitatemutualavoid- REPRODUCTION ance among individuals with overlapping home ranges (Hornocker Mountain lions are polygynous and males do not contribute to rear- 1969).MountainlionsdisplayaFlehmanresponsewhensmellingurine ing young. Like all felids, except African lions (Panthera leo), adult depositsinscrapes(Seidenstickeretal.1973).Femalesmayscrapeonly mountainlionsaresolitaryexceptwhenraisingyoung,dispersingwith wheninestrus(Maehr1997)and,ifso,suchscrapesmaybeusedby siblings,ormating.Malestendtohaverelativelylargehomeranges, malestomonitorthereproductivecyclesoffemalesaswellashome whichoverlapwiththoseofmorethanonefemale(Seidenstickeretal. rangeoccupancy.Mountainlionsalsoscratchlogsandtreesrepeatedly 1973;Loganetal.1986a;Pierceetal.1999b,2000b).Maleandfemale withtheirfrontclaws.Scratchmarksmayservethepurposeofmarking mountainlionslikelyrelyonauditoryandolfactorysignalstolocate homerangeareas(Schaller1972),butmaysimplybeforsharpening eachotherformating(Currier1983)(seeBehavior). claws(Seidenstickeretal.1973).Inaddition,felidshaveglandsinthe Estrous cycles in females with overlapping home ranges may cheek,whichoftenarerubbedagainstobjectsandfamilymembersas besynchronous(Padley1990).Associationsformatinggenerallylast anothermeansofcommunication(Macdonald1985). 2–5days(Beieretal.1995),duringwhichtimethepairmaycopulateup Hunting and Feeding. Mountain lions can jump vertically ≥3 m to70timesaday(Eaton1976).Femaleestrouscycleslastapproximately (Anderson 1983) and are capable tree climbers (Hornocker 1970). 8 days (Rabb 1959; Eaton and Velander 1977) and gestation is 82– Whenpursuedbycanids,mountainlionsmayseekrefugeintreesor 96 days (Young and Goldman 1946; Anderson 1983; Currier 1983). rocks(Hornocker1970;Seidenstickeretal.1973;Davisetal.1996). Mountainlionsmayreproduceduringanyseason(Robinetteetal.1961; Mostreportsofmountainlionsambushingpreyhavedescribedthem Ashmanetal.1983),butmanystudieshaveidentifiedseasonalbirth stalkingfromtheground(Koford1946;Hornocker1970;Wilson1984; pulses (Robinette et al. 1961; Ashman et al. 1983; Barnhurst and Beieretal.1995)withveryfewinstancesofattackingpreyfroman Lindzey1984;Loganetal.1986a;Ross1994).Timingofreproduction elevatedperch(Connolly1949).Theeffectofhuntingbyhumansonthe inmountainlionsmaybeaffectedbyclimateorpreyabundance(Logan behaviorofmountainlionsisunknown.Pursuitofmountainlionswith etal.1996;Pierceetal.2000a). P1:JDT PB336B-37 Feldhammer/0180G July21,2003 17:14 748 CARNIVORES Femaleshaveeightteats,butonlysixproducemilk(Lechleitner Patagonia(Wilson1984;BankandFranklin1998)andthedesertsof 1969).Thenumberofkittensbornperlittertypicallyrangesfromtwoto thesouthwesternUnitedStates(Cunninghametal.1995;Loganand four(Robinetteetal.1961;Ashmanetal.1983;RossandJalkotzy1992; Sweanor 2001), by successfully using the limited available cover to Loganetal.1996),butthismayvarywithpreyavailability,demography, catchprey.Inaddition,Pierce(1999)notedthatmountainlionswere andpopulationdensity.Femalesmayaveragemoreoffspringperlitter moresuccessfulkillingmuledeerinrelativelyopenhabitatcompared duringtheirfirstyearofreproductionandfewertowardtheendoftheir tothatinwhichdeerforaged.Thepursuitofdeerbymountainlions lives(Loganetal.1996).Moststudiesofmountainlionshavereported likelybeganinareaswithvegetativecover,butdeerthatfledintomore an equal sex ratio among young (Donaldson 1975; Anderson et al. openareaswithoutobstaclesduringthechaseweremorelikelytobe 1992;Loganetal.1996).Padley(1991),however,reportedthatfora caughtthanthosethatremainedinheaviervegetation. populationofmountainlionsinCalifornia,with12adultfemalesand Mountainlionscanthriveinextremelydryclimateswithlimited sevenlitters,sixofsevenkittenswhosesexhewasabletodetermine rainfall(Shawetal.1987;Cunninghametal.1995;Loganetal.1996; were male. In that population, adult males were scarce, and estrous Pierceetal.2000a);however,theseverelycoldtemperaturesofnorthern females were unable to locate an adult male with which to mate for CanadaandAlaskamaylimittheirdistributiondespitetheavailability almostayear. ofungulateprey.Mountainlionsmayavoidhumandisturbancewhen Kittensarebroughttokillsitesbytheirmotherasearlyas8weeks possible(VanDykeetal.1986),butcanpersistnearhumandevelopment ofage,butarenotweaneduntiltheyare2–3monthsold.Canineteeth (Beieretal.1995;Torresetal.1996). firstappearbetween20and30daysandmolarsatabout40daysofage. Laing(1988)suggestedthathabitatusebymountainlionsdidnot Somepermanentteetheruptat5–6monthsofageandpermanentca- differsignificantlyduringa24-hrcycle,butthatpatternmaydepend ninesappearduringtheeighthmonth,whenprimaryandpermanentca- on the availability of habitats. When habitat used by mountain lions ninesarepresent.Atweaning,kittensmayweigh3–4kg(Currier1983) fordenningorforcachingpreyisdifferentthanthatusedforresting, withlittlevariationinweightbetweenthesexesuntilabout30weeks then they will use different habitats during a diel cycle. Beier et al. ofage(Robinetteetal.1961). (1995)reportedthatmountainlionswithyounghuntedthroughoutthe Mountainliondensgenerallyarelocatedinrockyterrain(Logan night,butreturnedtothedenduringtheday.Densiteswerelocatedin etal.1996)orthickvegetation(Beieretal.1995;Bleichetal.1996). nearlyimpenetrablevegetation.Pierceetal.(1998)foundthatmountain Densarenotelaborate,butdoprovidehidingcover(Ross1994;Beier lionsfedoncachedpreyprimarilyaftersunsetandoftenrestedlong etal.1995)andthermalbenefits(Bleichetal.1996).Femaleswithkit- distancesfromthecachesiteduringtheday.Inaddition,Beieretal. tenshaverestrictedmovementpatternsuntiltheyoungareoldenough (1995)reportedthat,insomeinstances,mountainlionsrested>4km totravelawayfromtheden(Beieretal.1995).Amothermaymove from their cached prey. This behavior also was consistent with the her young to several different dens before they are weaned (Shaw reported use of high-elevation cliffs during the daytime and use of 1989). lower elevations with flatter terrain for hunting deer at night (Pierce etal.1998,2000b). Severalstudieshavedescribedseasonalchangesinelevationand ECOLOGY habitatuseassociatedwithchangesinhomerangeformountainlions Habitat. Thebroaddistributionofmountainlionsatteststotheirability preying on migrating populations of deer and elk (Cervus elaphus) toadapttoawidevarietyofhabitats.Becauseoftheirwidedistribution (Rasmussen1941;Seidenstickeretal.1973;Ackerman1982;Ashman (seeFig.37.5),definingpreferredhabitatformountainlionsislimited etal.1983;Murphy1983;Andersonetal.1992;Pierceetal.1999b).In- togeneralcharacteristicsspecifictodistinctregions,andtremendous deed,differencesinforageavailabilityassociatedwithseasonalranges variationoccursamongpopulations.Despitethelargerangeofhabitats ofpreyleadstopotentialdifferencesinthetradeoffbetweenforaging used by mountain lions, relatively few quantitative studies of habitat benefitandpredationriskfordeerandelk.Consequently,theremayex- selectionexist;manystudiespresentdescriptiveinformationwithout istdifferencesintheeffectsofmountainlionpredationontheseasonal referencetohabitatavailability.Forthosestudiesthatquantifiedhabitat foragingbehaviorandhabitatselectionofthoselargeungulates(Pierce selection,preyavailability,vegetation,andtopographyarethegeneral 1999). characteristicsthatdeterminesuitabilityformountainlions.Withinre- gionswhereavarietyofhabitattypesoccurs,structureofthevegetation Dispersal. Youngremainwiththeirmotherfor12–18months.Disper- andtopographyappeartobethemostimportantcriteriafordetermining salmayresultfromthemotherabandoningtheyoung(Seidensticker habitatuse(Lindzey1987). etal.1973),butitislikelythatthereissomeaggressionbythemother Most studies of habitat selection for mountain lions in western directedtowardtheyoungtopreventthemfromfollowingher(Hansen NorthAmericasuggestthatvegetativeandtopographiccover,inaddi- 1992).Dispersalofyoungfromthemotheriscoincidentwiththefemale tiontosteepslopesandhigherelevations,arepreferredresting,hunting, comingintoestrous;adultmaleswillkillyoung(YoungandGoldman anddenningsites,whereasopenagriculturallands,sagebrush(Arteme- 1946; Ackerman et al. 1984; Spreadbury 1989; Logan and Sweanor siatridentata)grasslands,andopenmeadowsandpasturesareavoided 2001).Duringtheperiodofdispersal,mountainlionsareoftenreferred (Murphy 1983; Logan and Irwin 1985; Laing 1988; Lindzey et al. to as “transients” (Hornocker 1970). Transients, as opposed to “res- 1989).Ashmanetal.(1983)suggestedthatthermalcharacteristicscause idents,” are individuals that do not have a defined home range area mountain lions to select north-facing slopes at high elevations, with withinapopulation. morevegetationandcoolertemperatures,inthesummer.South-facing Dispersalisarelativelyriskyperiodduringthelifecycleformany slopes with little snow cover were selected in winter. Those habitats species (Baker 1978), and survivorship likely declines for mountain werestronglycorrelatedwiththedensityofdeer.Ruggedorsteepter- lions during the dispersal period (Logan and Sweanor 2001). Tran- rain,withadequatevegetativecover,maybecriticalforstalkingand sientsaremorelikelythanresidentmountainlionstobeinvolvedin catchingprey(Ashmanetal.1983;LoganandIrwin1985;Laing1988) depredationincidentsorconflictswithhumans,astheyattempttolo- orforprovidinghidingcoverandprotectionfromthermalextremesfor catefoodwithouttheadvantageofanestablishedhomerange(Torres young at denning sites (Belden et al. 1988; Ross 1994; Bleich et al. etal.1996).Malesaremorelikelytodispersefromtheirnatalranges 1996). thanarefemales,andmalestendtodispersefurther(Andersonetal. Dense hiding cover is preferred by mountain lions for hunting 1992;Sweanoretal.2000). (Russell 1978; Beier et al. 1995). Indeed, mountain lions were more Mountainlionscandispersenearly500kmfromtheirnatalhome successfulhuntingpronghorn(Antilocapraamericana)thatinhabited range(LoganandSweanor1999).Consequently,mountainlionhabitat ruggedterrainwithmorevegetationthanpronghornthatoccurredin throughoutNorthAmericaisconsideredalmostcontiguousonalarge open prairie habitat (Ockenfels 1994). Mountain lions, however, can scale, with the exception of the isolated populations in southeastern inhabit open or sparsely vegetated habitats, such as the plateaus of Florida. Nevertheless, mountain lion populations can be isolated by P1:JDT PB336B-37 Feldhammer/0180G July21,2003 17:14 MOUNTAINLION(Pumaconcolor) 749 residentialdevelopmentorgeographicfeaturessuchasdesertbasins. FEEDINGHABITS Reductioninthesizeofhabitat“islands”forpopulationsofanyspecies Mountainlionskillandeatvertebratepreyalmostexclusively(Lindzey increasesthechanceofextirpationforthatpopulation(MacArthurand 1987). Vegetation often is ingested because it adhered to a carcass Wilson1967). ortohelpwithpassageofparasitesandhairfromthegut(Robinette Sweanoretal.(2000)describedametapopulationstructure(Levins et al. 1959; Anderson 1983). The historical distribution of mountain 1970)formountainlionslivinginbasinandrangehabitatsoftheSouth- lionsthroughoutNorthAmericacoincidedwiththedistributionoftheir west.Mountainrangesprovideislandsofsuitablehabitatthatsupport primaryprey—deer.MoststudiesinNorthAmericaidentifieddeeras semi-isolated populations of mountain lions. Those populations are the most frequent prey in diets of mountain lions (Hornocker 1970; maintainedthroughimmigrationbydispersers(primarilymale)from Shaw1980;Ackerman1982;Loganetal.1996;Rossetal.1997;Pierce othermountainrangesandrecruits(primarilyfemale)fromwithinthe etal.2000a). population.Thebasinsbetweenthemountainsarenotconsideredsuit- Despitethecongruenceofdeerandmountainliondistributionsin ablemountainlionhabitat(Germaineetal.2000)andactasbarriersthat NorthAmerica,lionsaregeneralistpredators(Andersonetal.1992; maylimitgeneflow.Protectingsourcepopulationsandhabitatstepping LoganandSweanor1999).Theydopreyonotherlargeungulatesin- stonesmaybeexceptionallyimportantinconservingsubpopulationsof cludingmoose(Alcesalces;RossandJalkotzy1996),elk(Hornocker mountainlionsthatexistinametapopulationstructure(Sweanoretal. 1970),feralhorses(Equuscaballus;Turneretal.1992),feralpigs(Sus 2000). Although concerns about habitat fragmentation and interrup- scrofa;Harveson1997;Sweitzer1998),andwildsheep(Oviscanaden- tion of gene flow are legitimate, Ernest et al. (2003) have cautioned sis; Cronemiller 1948; Harrison 1990; Wehausen 1996; Ross et al. thatithasnotbeendemonstratedthatmountainlionsconformtothe 1997;Schaeferetal.2000).Mountainlionsalsofeedonsmallerprey assumptionsinherentinbasicmetapopulationmodels. suchaslagomorphs(Shaw1980;Ackermanetal.1984);groundsquir- Survivorship of adults likely varies within most populations on rels (Spermophilus spp.; Seidensticker et al. 1973); beavers (Castor anannualbasis(Lindzeyetal.1988),butcanbeaffectedsignificantly canadensis;Padley1991);porcupines(Erethizondorsatum;Sweitzer byhunting(Anderson1983).Destructionofhabitatalsocanhavelarge etal.1997);smallcarnivoresincludingraccoons(Procyonlotor),gray impactsonthedemographyofmountainlionpopulations.Forexample, foxes(Urocyoncinereoargenteus),andskunks(Cashmanetal.1992; fragmentationofhabitatcaninhibitdispersalandincreasecompetition Beieretal.1995);andbirdssuchaswildturkeys(Meleagrisgallopavo), forresources(Beieretal.1995;Maehr1997).Furthermore,realestate grouse,andquail(Ashmanetal.1983;Ackermanetal.1986;Maehr developmentmaylimitpreypopulations,increasedepredationevents etal.1990).Currier(1983)listed41nondomesticspeciesofvertebrates (Shaw1980;Cunninghametal.1995;Torresetal.1996),andincrease identifiedinthefecesofmountainlionsfromNorthandSouthAmerica. collisionswithautomobiles(Maehr1997;Beieretal.1995). Domesticsheep,goats,cattle,horses,dogs,andcatsalsoareconsumed whenpopulationsofmountainlionsareinproximitytolivestockop- Disease and Parasites. Anderson (1983) suggested that the widely erationsorareasofhumanhabitation(Shaw1980;Torresetal.1996). held opinion that mountain lions are relatively free of parasites and Attacksonhumansbymountainlionsarerare(Beier1991);however,in diseases reflected a lack of specific research rather than reality. For mostinstances,victimsoffatalattacksweretreatedaspreyandeither example,basedonhisliteraturereview,Anderson(1983)reportedthe draggedtocoverorpartiallyconsumed(Beier1991;J.Banks,Califor- occurrence of feline panleukopenia virus was low, but Paul-Murphy niaDepartmentofFishandGame,pers.commun.,1996).Remainsof etal.(1994)detectedtiterstothevirusinnearly100%oftheanimals bobcats(Lynxrufus),coyotes(Canislatrans),andothercompetingcar- thattheytested.Furthermore,Adaska(1999)reportedthefirstcaseof nivoresoccasionallyoccurinfecesofmountainlions.Also,speciesthat coccidioidomycosisdetectedinamountainlion,andJessupetal.(1993) scavengeonlionkills,includingeaglesandturkeyvultures(Cathartes documentedthefirstoccurrenceoffelineleukemiavirusinfectionina aura),canbekilledbymountainlionsguardingapreycache.Although free-rangingmountainlion.Evermannetal.(1997)reportedontheoc- intraspecific aggression leading to death in mountain lions may oc- currenceofpumalentivirusspecificallyinmountainlionsinthestateof cur as a result of competition for resources or mating opportunities Washington.Yamamotoetal.(1998)foundoverallseroprevalanceof (Robinetteetal.1961;Hornocker1970;Sweanor1990;Pierceetal. bartonellosisin26of74mountainlionstheyexaminedfromCalifor- 1998),instancesofcannibalismbymountainlions,inwhichthecarcass nia,amongthefirstevidenceofthisconditiondetectedinwildfelids. hasbeenlargelyconsumed,havebeenreportedfrequently(Lesowski Hence,itappearsthatAnderson’s(1983)admonitionwasinsightful. 1963;Donaldson1975;Ackermanetal.1984;Spreadbury1989). Mountain lions potentially are susceptible to many infectious agentsthataffectdomesticcats(Paul-Murphyetal.1994)aswellasto Selection of Prey. Numerous authors have described the sex, age otherdiseases(summarizedbyAnderson1983).Someofthese,includ- class, and condition of prey killed by mountain lions. Hornocker ingfelinepanleukopeniavirus,havethepotentialtoaffectmorbidity (1970),SpaldingandLesowski(1971),Shaw(1977),Ackerman(1982), and mortality (Paul-Murphy et al. 1994), may limit growth of wild Ackermanetal.(1984),andMurphy(1998)allsuggestedthatvulnera- populations(Anderson1983),andhaveimplicationsfortheconserva- bilityofindividualpreymaybethemostimportantfactorintheirselec- tionandpersistenceofaviablepopulationoftheendangeredFlorida tionbymountainlions.Thoseinvestigationsidentifiedindividualsin panther(Roelkeetal.1993).Foley(1997)concludedthatepizooticdis- youngerorolderageclassesorinpoorerconditionasbeingselectedby easeslikelyarenotaprimarythreattopopulationsofmountainlionsin mountainlions.Amongadultdeerandbighornsheep,mountainlions thewesternUnitedStates.Fromahumanhealthperspective,rabieshas alsomaypreyonmalesselectively(Hornocker1970;Ackerman1982; beendetectedamongmountainlions(Storer1923)andshouldbeof Harrison 1990), especially when males are in a weakened condition concerninallcasesinvolvingattacksonhumans(Kadeskyetal.1998). followingtherut(Robinetteetal.1959;Shaw1977;Harrison1990)or Parasitic infections among mountain lions are not uncommon; duringdroughtconditions(LoganandSweanor2001).Studiesofprey Anderson (1983) listed ≥40 species of parasites that have been col- selection,however,requirecomparisonswithavailabilityofprey.Most lected.Forresteretal.(1985)andWaid(1990)listedadditionalinter- studiesofpreyselectionbymountainlionshavebeenlimitedbylack nalparasitesnotnotedbyAnderson(1983).Themajorityofparasites ofinformationonavailabilityofpreyorbybiasesindetectingprey. recordedhavebeeninternal(protozoans,trematodes,cestodes,ornema- Anderson(1983)attemptedtocomparesexandageratiosofdeer todes),butmites,ticks,andinsectsareknowntoparasitizemountainli- killedbymountainlionstotheestimatedratiosinthepopulationsof ons.Penceetal.(1987)notedahighdegreeofoverdispersion(i.e.,afew deerforsixstudyareas,andconcludedthatthesamplingmethodsused mountainlionsharboredthemajorityofparasitescollectedandmost inthosestudiespreventedcleartestingofanyhypothesisregardingprey hadfewornoparasites)inhelminthspeciescollectedfromthevisceraof selection.Sincethen,Rossetal.(1997)reportedselectionforyoung mountainlionsinTexas.Ingeneral,mountainlionshavebeendescribed bighorn sheep by mountain lions. Pierce et al. (2000a) reported that asremarkablyfreeofexternalparasites(Currier1983),butourexpe- mountain lions selected deer in young and old age classes, and that riencehasbeenthatticksarecommonlyencounteredduringhandling. femaleswereselectedamongadultdeer.Preferenceforfemalesamong P1:JDT PB336B-37 Feldhammer/0180G July21,2003 17:14 750 CARNIVORES adultmuledeeralsohasbeenreportedforotherpopulationsofmountain pigs(Craig1986)and,inUtah,theykilledtwiceasmanyblack-tailed lions(BleichandTaylor1998).Morerecentinvestigationssuggested jackrabbits(Lepuscalifornicus)duringwinter(Ackermanetal.1984) thatmountainlionsdonotselectpreyinpoorcondition(Kunkeletal. thanduringsummer.Adultmaledeermaybetakenatahigherratedur- 1999; Pierce et al. 2000a); however, bone marrow fat has been the ingwinterwhentheyareinweakenedconditionfromtherut(Robinette primaryindexusedtodeterminepreyconditionbymostinvestigators. etal.1959;Shaw1977).Thevulnerabilityofnewborncalvesresultsin Althoughpercentagebonemarrowfatwasnotrelatedtopreyselection highdepredationratesoncattleinArizona(Shaw1977;Cunningham bymountainlions(Kunkeletal.1999;Pierceetal.2000a),theyselected etal.1995). for older animals. Thus, percentage marrow fat may not adequately reflect other forms of weakness detected by mountain lions (Pierce POPULATIONDENSITYANDDYNAMICS etal.2000a). Kunkeletal.(1999)determinedthatmountainlionskilleddeer Mountain lions coexist in a system of individual home ranges with withshorterdiastemaethanthosekilledbywolvesorhunters,butvalues varyingamountsofoverlap(Seidenstickeretal.1973;Hemkeretal. ofmarrowfatdidnotdifferbetweendeerkilledbymountainlionsand 1984).Meanhomerangesizeanddistributionofmountainlionscanbe wolves.Sizeofpreyalsoappearstoaffectselectionbymountainlions. affectedbysex(Seidenstickeretal.1973)oravailabilityofresources Theyselecteddeeroverelk,andelkovermooseinMontana(Kunkel suchasprey(Pierceetal.1999b,2000a).Andersonetal.(1992),how- etal.1999).RossandJalkotzy(1996)reportedthatmalemountainlions ever, concluded there was no relationship between prey density and weremorelikelytokillmoosethanwerefemales.Bodysize,however, frequencyofusebymountainlionsofareasinhabitedbydeerandelk. did not appear to be important for selection of mule deer preyed on Theyfeltthatotherfactors,suchassuitablehabitatforhunting,may bymountainlionswhencomparedwiththosekilledbycoyotesduring affectpreyavailabilityindependentlyofpreydensity(Kruuk1986)and winter,whenyoungdeerwereunavailable(Pierceetal.2000a). mayultimatelyaffectthehomerangesizenecessaryformountainlions Sex and age of mountain lions likely affect their diet. Solitary tobesuccessful. mountainlionsmaybemorelikelytoeatsmallerpreythandofemales Homerangesofmountainlionsaredelineatedbyvisualandolfac- withkittens(Ackerman1982).Ackermansuggestedthatkillinglarge torymarkingbehaviors,andadultmalestendtohavelargerhomeranges prey to provide for their offspring would be a necessary strategy for thanfemales(Seidenstickeretal.1973;Loganetal.1986a;Pierceetal. mothers,andthatpopulationsofmountainlionscouldnotexistinareas 1998) (Table 37.2) (see Behavior). Male home ranges often overlap devoidoflargeungulateprey.Pierceetal.(2000a),however,reported thoseofseveralfemalesbuthavelimitedoverlapwiththoseofother thatfemalemountainlionswithkittens(≤6monthsold)weresignifi- males (Seidensticker et al. 1973; Murphy 1983; Logan and Sweanor cantlymorelikelytokillyoungdeer(<1yearofage)thanweresingle 2001),whereasthehomerangesofadultfemalesoftenoverlapthose adultfemalesormales.Birthpulsesofmountainlionpopulationsoften ofotherfemalesextensively(Seidenstickeretal.1973;Sweanoretal. coincidewiththebirthpulseoftheirprimaryprey(LoganandSweanor 1996;Pierceetal.1999b,2000b;LoganandSweanor2001).Exten- 2001; Pierce et al. 2000a), suggesting that timing of reproduction in siveoverlapamongmalehomeranges(Andersonetal.1992;Sweanor mountain lions may be dependent on the availability of vulnerable, 1990)andlimitedoverlapoffemalehomeranges(Harrison1990)also youngprey.Adultfemalesthatarelactatingmaynotbeabletofastfor havebeenreported.Additionally,mountainlionsmayavoideachother extended periods between unsuccessful attempts to catch larger prey temporarily,abehaviortermed“mutualavoidance”(Hornocker1969), (Pierceetal.2000a). butnoinvestigationshavetestedforthedominancereversalnecessary Latitudecorrelatesstronglywithsizeofpreyselectedbymoun- todemonstratetrueterritorialityinmountainlions(Kitchen1974). tainlions(Iriarteetal.1990;Maehretal.1990).Intemperatezones, Hornocker(1969,1970)andSeidenstickeretal.(1973)suggested theytendtokilllargerungulates,whereasmountainlionsintropical thatmountainlionpopulationswereselfregulating(seePredator–Prey environmentshaveahigherfrequencyofsmallpreyintheirdiet.The Dynamics).Theydescribedsocialbehaviorssuchasmutualavoidance, complicating effect, however, of competition with the jaguar on this territorialmarking,andcannibalismasmechanismsthatlimiteddensi- patternoflatitudinalpreyvariationisunknown.Additionally,variation tiesofmountainlions.Transientmountainlionswereunabletosecure inpreyselectionisnotableforsomepopulationsofmountainlionsas permanenthomerangeareasunlessthehomerangeareaofaresident vulnerabilityoravailabilityofpreychanges.Duringthewetseasonin adultbecamevacant.Thispatternoccurredindependentlyofpreydensi- coastal California, mountain lions increased predation rates on feral ties.Lindzeyetal.(1994)alsoconcludedthatthedensityofamountain T37.2. EstimatedhomerangesizeandaveragedensityofmountainlionsfromNorthAmericanstudiesusingtheminimumconvexpolygon method(Mohr1947) Males Females Study Location n Range(km2) n Range(km2) Lions/100km2 RossandJalkotzy1992 Alberta 6 334 21 140 1.9(RA,H),4.2(T) Cunninghametal.1995 Arizona 5 196 2 109 —(H) BeierandBarrett1993 California 2 767 12 218 1.1(RA) Hopkins1989 California 4 199 7 84 3.6(T)a Andersonetal.1992 Colorado 6 256 7 309 1.1(RA,H) Maehretal.1991 Florida 8 558 10 191 — Seidenstickeretal.1973 Idaho 1 453 3 233 0.6(RAb,H) Ashmanetal.1983 Nevada 7 574 6 178 —(H) Loganetal.1996 NewMexico 23 187 29 74 1.7(RA) Murphy1983 Montana 2 462 5 202 7.1(RA,H) Pittmanetal.2000 Texas 6 349 5 206 0.4(RA,H) Penceetal.1987 Texas 1 628 5 143 — Hemkeretal.1984 Utah 1 826 4 685 0.4(T) Logan1983 Wyoming 2 320 2 73 1.5(RA,H),3.9(T) N:RA,Densityofresidentadults;T,densityoftotalpopulation;H,huntedpopulation. aFromAndersonetal.(1992),Table23. bEstimatedfromSeidenstickeretal.(1973),Table6,Fig.16. P1:JDT PB336B-37 Feldhammer/0180G July21,2003 17:14 MOUNTAINLION(Pumaconcolor) 751 lion population in Utah was independent of the density of their pri- independentlyfocusedoneitherthepredatorortheprey,therebylimit- mary prey, mule deer, because the population of mountain lions did ing conclusions that can be drawn about interspecific effects (Pierce notincreaseattheratepredictedbytheincreaseinprey.Nonetheless, 1999). In most instances, viable populations of mountain lions are the population of mountain lions did increase by one third after an dependent on populations of large ungulate prey (Ackerman 1982; increase in the deer population. Long time lags betweenfluctuations Anderson1983).Mostungulatesthatarepreyedonbymountainlions, inpreypopulationsandresponsesinmountainlionpopulationsmake includingdeer,elk,andmoose,areaffectedbydensity-dependentpro- determiningthetruerelationshipbetweenpredatorandpreydifficult cesses(McCullough1979;Boyce1989;Bowyeretal.1999;Keechetal. (Schaller1972),andemphasizetheneedforlong-termresearchwhen 2000).Therefore,determiningtheeffectofpredationbymountainlions workingwithlargecarnivores(Pierce1999). onthepopulationdynamicsoftheirpreyrequiresanunderstandingof To invoke social regulation for a population (Hornocker 1969, thosedensity-dependentprocessesandallfactorspotentiallylimiting 1970;Seidenstickeretal.1973),itmustbedemonstratedthatthepop- thepopulationincludingweather,resources,andotherpredators. ulationisnotlimitedbycompetitionforresources(WatsonandMoss In the ecological systems that mountain lions inhabit, both ex- 1970).Mutualavoidancedoesnotpreventpassivecompetitionforre- ploitative and interference competition with other predators likely sources.Pierceetal.(2000b)demonstratedthatcompetitionforpreyby occur. Niches of wolves (Kunkel et al. 1999), coyotes (Pierce et al. mountainlionsoccurredinapatternthatwouldbeexpectedfornonter- 2000a; Harrison 1990), bears (Murphy 1998), bobcats (Koehler and ritorialspeciesthatdonotexcludeeachotherfrompreyresources.Fur- Hornocker1991),andjaguars(Iriarteetal.1990)overlapextensively thermore,ifmountainlionsengagedinaterritorialsystemthatexcluded withthatofmountainlions.Nichepartitioningviahabitatuseandprey individualsfromresourcesbeyondwhatwouldbeexpectedforapopu- selectionmayallowforcoexistenceofmountainlionswiththoseother lationlimitedbycompetition,suchcostlybehaviorcouldhaveevolved carnivores.Insomeinstances,scavengingoftheirfoodcachesrequires onlyifitmaximizedreproductionforindividualsthatwereterritorial mountainlionstoincreasepredationrates(Harrison1990).Inaddition, and,ultimately,wouldnotleadtopopulationlimitation(McCullough mountainlionsoftenkillsmallerspeciesofcarnivores,suchasbobcats, 1979).Hemkeretal.(1984)concludedthatpopulationsizeofmoun- withoutfeedingonthem(KoehlerandHornocker1991).Conversely, tainlionswasprimarilylimitedbythepopulationofprey,aconclusion mountainlionshavebeenkilledbypacksofwolves(WhiteandBoyd supportedbyPierceetal.(2000b)andLoganandSweanor(2001). 1989;BoydandNeale1992).Thoseobservationsalsosuggestthatcom- Thedensityofmalesmaybelimitedbyintraspecificaggression petitionisanimportantfactoraffectingthepredator–preydynamicsof to maximize access to females, but mountain lion populations on a multipredatorsystemsthatincludemountainlions. wholelikelyarenotlimitedbysocialbehavior.Inaddition,dispersalby Mountainlionsareanimportantlimitingfactorforsomeungulate youngmountainlionsappearstobeindependentofpopulationdensity species(Hornocker1970;Shaw1980).Shaw(1980)estimatedthatlions (Seidenstickeretal.1973;Hemkeretal.1984;RossandJalkotzy1992; annuallyremoved15–20%ofthemuledeerpopulationontheKaibab Loganetal.1996),andmountainlionpopulationnumbersparalleltheir PlateauinArizona.Andersonetal.(1992)estimatedthatmountainlions preypopulations(Lindzeyetal.1994;Loganetal.1996;CoxandStiver annuallykilled8–12%ofthemuledeerpopulationontheUncompah- 1997)(Fig.37.6).Furthermore,LoganandSweanor(2001)reporteda grePlateau,Colorado.InAlberta,asinglemountainlionkilled8.7% pattern of density-dependent growth for a mountain lion population, (n = 11) of the early-winter bighorn sheep population and 26.1% providingadditionalevidencethatcompetitionisanimportantfactor (n=6)oftheyoung(Rossetal.1997). affectingtheirpopulationdynamics. Mountainlionpredationmayreducetheseverityoffluctuationsin preypopulations(Hornocker1970)byslowingthegrowthrateandre- ducingovershootsofresource-basedcarryingcapacity(K).Limitation PREDATOR–PREYDYNAMICS andregulation,however,aredistinctlydifferentmechanisms.Limitation Few long-term studies of predator–prey dynamics have been condu- impliesthatthenumberofpreyisreducedthroughdecreasedproduc- cted that include mountain lions. Unfortunately, many studies have tionorincreasedloss,andthereforeanysourceofpredationislimiting (Sinclair1989;Boutin1992).Limitationslowstheincreaseofapop- 25,000 25 ulationfromthegrowthrateitwouldhaveachievedintheabsenceof thepredator.However,ifthepreypopulationcontinuestoincrease,the proportionofpreyremovedbythepredatorisreduced.Consequently, 20,000 20 preypopulationslimitedbypredatorscancontinuetogrow,although M est ou ataslowerratethanintheabsenceofpredation,untiltheyreachK. v n Regulationimpliesthatrateofremovalbythepredatorchanges eer har 15,000 15 tain lio watiwthhtihcehpporepdualatotirosnkoilflpprreeyy.;Tashipsrpeyhennuommbeenrosninrcerseualtsse,frsoomdoaensinthcereraastee e d 10,000 10 n h inthenumberofpredators(numericalresponse),theeasewithwhich Mul arve (thHeoyllfiinngd1a9n5d9k).ilRlpegreuyla(tfiuonncbtiyonaaplrreedsaptoonrseev)e,notruaalclyomstboipnsatthioeninocfrbeoasthe s 5,000 5 t ofthepreypopulationandcausesadeclinetolowerdensities,which ultimatelyresultsinlowerpredationrates.Suchfeedbackmechanisms cancauseapreypopulationtofluctuatebetweenlow-andhigh-density 0 0 equilibria, both of which are below K. This multiple-equilibria sce- 1930 1940 1950 1960 1970 1980 1990 2000 narioisfrequentlytermeda“predatorpit”(Haber1977;Bergerudetal. Year 1983;MessierandCrete1985).Functionalresponsesofthepredator may ultimately determine whether a species has the capacity to reg- Mule deer harvest ulateapreypopulation(Messier1994).Nonetheless,determiningthe functionalresponsecurveforaspeciesrequiresanunbiasedmeasureof Mountain lion harvest predationratethroughouttherangeofpopulationdensitiesoftheprey, andcontrolledremovalstudiesarenecessarytodeterminethecondi- F37.6. Harvestofmuledeer(Odocoileushemionus)andmountainlions tions that may cause multiple equilibria (i.e., regulation) to occur in (Pumaconcolor)inNevada.Muledeerharvestshownincludesmalesonly. predator–preysystems(VanBallenbergheandBallard1994). Mountainlionharvestshownincludesdepredationremovalsandsporthunting Attemptstomeasurepredationratesofmountainlionshavebeen (sporthuntingestimatedto1967).S:DatafromS.Stiver,Nevada madeforstaticpopulationsofprey.Usinganenergeticsmodel,Acker- DepartmentofWildlife,pers.commun.,2001. manetal.(1986)estimatedthatadultmalemountainlionswouldkill P1:JDT PB336B-37 Feldhammer/0180G July21,2003 17:14 752 CARNIVORES adeerevery8–11days,adultfemaleswouldkillevery14–17days,and variable,callingintoquestiontheutilityofthatmeasurement.Despite afemalewiththreejuvenileswouldkillevery3.3days.Connolly(1949) theproblematicnatureofdiscriminatingamongindividuallions,Beier reportedthatanadultmountainlionkilledonedeerevery9.7days.Pre- andCunningham(1996)conductedseveraldetailedanalyses.Theyfelt dationratesonbighornsheepandmuledeerbyfemaleswithkittens itispossibletodetectchangesinrelativeabundanceofmountainlions ranged from 0.7 to 2.1 ungulates/week (Harrison 1990). Beier et al. usingtrackingtechniquesatthelocallevel.Nonetheless,themigratory (1995) determined that mountain lions killed 48 large and 58 small natureofsomemountainlionsmakesitproblematictodefinepopula- mammals/year. Rate of predation by mountain lions can vary exten- tions(Pierceetal.1999b),withseriousimplicationsfortheuseoftrack sively(RossandJalkotzy1996),andisdependentonanumberoffactors surveysforestimatingchangesinpopulationsize.Tracksurveyscould includingthenumberandageofyoung(Ackermanetal.1986),season beusefulforestimatingrelativeuseofaspecificgeographicareaby (Pierce1999),andextentofcompetitionfromotherpredators(Kunkel mountainlions,butinferencesaboutpopulationsizeovertimearecon- etal.1999)orscavengers(Harrison1990).Thosestudiesgiveinsight foundedbecauseitisdifficulttodefineanopenpopulation.Theuseof intothebehaviorofmountainlionsandtheirpossibleeffectsonprey tracksurveysoverlargegeographicscalestoindexrelativeabundance populations,butthequestionofwhethermountainlionscanindepen- ofmountainlions(Smallwood1994;SmallwoodandFitzhugh1995) dentlyregulateapreypopulationremainsunanswered. hasbeenattempted,butlikelydoesnotprovidethepowernecessaryto Mountainlionshavebeenimplicatedasregulatingawildhorse detectsuchchanges. population(Turneretal.1992),andarethoughttohavecausedpopula- Mountain lions frequently are captured to allow attachment of tionsofporcupinestodeclinethroughpredation(Sweitzeretal.1997). radiotransmitters.Capturetechniquesofteninvolvethepursuitofani- In addition, some bighorn sheep populations may have declined due malswithhounds,followedbychemicalimmobilization(Loganetal. to avoidance of high-quality forage in response to predation risk by 1986b;Jessupetal.1986).Physicalretrievalofimmobilizedanimals mountainlions(Wehausen1996).Inthoseinstances,muledeerwere (Hornocker 1970) is necessary if they are sedated in a location high theprimarypreyformountainlions.Systemswithmultiplepredators abovetheground.McCownetal.(1990)describedaportablecushion and multiple prey are more likely to be regulated by predation and thatlessenedtheprobabilityofinjurytomountainlionsfallingfrom toproducepredatorpits(Gasawayetal.1992).Muledeerpopulations trees.Davisetal.(1996)developedamethodtosafelylowerimmobi- cankeepmountainlionnumbershigh.Ifpopulationsofalternativeprey lizedmountainlionsfromtreesandcliffs.Footsnareshavebeenused increase,mountainlionsencounterthosespeciesmorefrequentlyand safelyandsuccessfullybysomeinvestigators(Loganetal.1999;Pierce predationratesmayincrease,causingalternativepreytodecline.Bleich etal.2000a),andareadvantageousinsomesituations. etal.(1997)noted,however,thatunlessfemalemountainsheepwere Radiotelemetry has been used extensively to determine the dis- killedinsignificantproportions,predationbymountainlionsprobably tributionofmountainlionsinnumerousstudies,fromwhichdensity isnotanimportantfactorinthepopulationdynamicsofthoseungulates. estimateshavebeeninferred.Captureandrecapturemethodsalsohave Several studies examining the population dynamics of deer and beenusedtoestimatepopulationdensities.Reliabilityofestimatesob- mountainlionssuggestthatmountainlionsdonotdeterminetheulti- tainedwiththosetechniquesisvariable(LoganandSweanor1999),but matesizeofdeerpopulations.Instead,otherfactors(especiallyforage densitieshavebeenestimatedat0.3–2.2adultmountainlions/100km2. resources)appeartobemoreimportantdeterminantsofdeerpopula- Pierce et al. (2000b) estimated the abundance of mountain lions by tions.Forexample,LoganandSweanor(2001)determinedthatmoun- maintaininganintensiveandconstantefforttocaptureandradio-collar tain lions were not responsible for the decline of mule deer in New alllionsdetectedonamuledeerwinterrange.Theythenusedaerial Mexico, but that a lack of forage resources because of drought was telemetrytoestimatethenumberofmountainlionspresentperaerial- responsible. Pierce et al. (1999a) came to a similar conclusion for a telemetryday,andwereabletodeterminetheirabsoluteabundancefrom populationofmuledeerintheeasternSierraNevadaofCalifornia.In yeartoyear.Smallwood(1997)notedthatmostvariationindensities thatstudy,mountainlionnumbersdeclinedprecipitouslyasdidthedeer ofmountainlionscanbeattributedtothespatialextentofindividual numbers,butwithalagof8years.Longtimelagsbetweenchangesin studyareas,andsuggestedthatfieldstudieswouldbemoremeaningful preypopulationsandresponsesinmountainlionpopulationsincrease if they spanned larger areas, a variety of land uses and habitats, and thedifficultyofdeterminingtherelationshipsbetweenmountainlion greaterperiodsoftimethanmostconventionalstudies. populationsandpreypopulations(Schaller1972),andemphasizethe Moleculartechniqueshavebeendevelopedthatallowinvestigators needforlong-termstudies(Pierce1999). toidentifyindividualmountainlionsusingDNAobtainedfromblood, tissue,orhairsamples(Ernest2000a,2000b)andfromfeces(Ernest etal.2000).Thesetechniquesdependonobtaininggood-qualityDNA, MANAGEMENTANDCONSERVATION whichismoredifficultwhenusingfeces(Ernest2000a).FecalDNA Management Techniques. Demographic information is difficult to hasbeenusedtoidentifyindividuallionsoccurringwithincertainge- obtainforpopulationsoflarge,crypticpredatorslikemountainlions. ographic areas (Ernest et al. 2000) or associated with particular kill Tracksurveyshavebeenatraditionalmethodofdeterminingpresence sites for large mammals (Hayes et al. 2000). Use of this technique orabsenceofmountainlionsaswellasestablishingestimatesofrelative to determine the absolute number of mountain lions occurring in a abundance.Variousinvestigatorshaveattemptedtodistinguishamong particulargeographicareaissubjecttobiasesassociatedwiththeirdis- lionsusingtrackcharacteristicsuniquetoindividualanimals(Currier tributionandfrequencyinthearea.Althoughitispossibletoestimate etal.1977;FitzhughandGorenzel1985;VanDykeetal.1986)ortrack minimumnumbersofindividualspresent,theprobabilityofdetecting measurements(Currieretal.1977;Shaw1983;FitzhughandGorenzel all individuals using molecular techniques is a function of sampling 1985)torecognizeindividuals.Noneoftheseinvestigatorsbelievedit effort. wasreliabletodistinguishamongindividualmountainlionsusingonly The literature is replete with estimates for home range sizes of tracks. mountainlionsthathavebeendeterminedusingland-basedoraerial Smallwood and Fitzhugh (1993) used a sophisticated statistical telemetry.However,globalpositioningsystem(GPS)technologyraises technique(multiplegroupdiscriminantanalysis)inanattempttode- questionsregardingpreviousstudies.Bleichetal.(2000)describedthe velop a method to discriminate among individual animals based on resultsfromGPScollarsontwoadultmalemountainlions.Patternsof measurementsandcharacteristicsoftracks.However,Grigioneetal. movementwerevastlydifferentandhomerangesweremuchlargerthan (1999)determinedthatSmallwoodandFitzhugh(1993)hadusedan wereestimatesfromsimultaneousaerialtelemetryflightsconductedon inappropriatemethod.Basedonadditionalanalyses,theyconcludedit aweeklybasis.SomeGPScollarsincorporateswitches(Bleichetal. wasunlikelythatindividualmountainlionscouldbedetectedusingdis- 2000)thathavethepotentialtobeusefulinpredictingmountainlion criminantanalysis.Furthermore,Grigioneetal.(1999)concludedthat activity;Janisetal.(1999)describedandquantifiedtheuseoftraditional themostcommonlyusedmeasurement(widthofheelpad)fordistin- veryhighfrequencytransmittersequippedwithtipswitchestoestimate guishingamongmountainlionsbasedontheirtrackswasalsotheleast activityofmountainlions. P1:JDT PB336B-37 Feldhammer/0180G July21,2003 17:14 MOUNTAINLION(Pumaconcolor) 753 Translocation of mountain lions as a technique for managing viablepopulationsofmountainlionswillbecomeincreasinglyimpor- “problem” lions (i.e., animals that have preyed on livestock or that tant(Torres1997). occupyareasadjacenttohumanhabitation)iscontroversialandisin- Sporthuntingofmountainlionsoccursinthemajorityofstates consistentwithmanagementpoliciesinsomestatesbecauseofpotential thathaveviablepopulationsofmountainlions,andharvestisamethod liabilities.Generally,survivaloftranslocatedlionsisverylow.Forex- bywhichwildlifemanagersattempttocontrollionnumbers.Increas- ample,Ruthetal.(1998)describedanexperimentinwhich14animals ingly,however,theconceptofsporthuntinghascomeundercriticism, weremovedandreleaseddifferentdistances(X¯ =477km)fromtheir andhuntingofmountainlionshasbeeneliminatedinCalifornia,and locationsofcapture.Nineofthoseindividualsdiedand,overall,sur- madeextremelydifficultinotherstatessuchasOregonandWashington vivalwaslowerthanthatofreferenceanimalsthatremainedwithintheir byrestrictionsontheuseofhoundstobringanimalstobay.Nonethe- originalhomeranges(Ruthetal.1998).Theyconcludedthattranslo- less,carefullyregulatedsporthuntingremainsanimportantrecreational cationwasmostsuccessfulwhenmountainlionswere12–27months pursuitandisemployedasamethodofsustainingmountainlionpop- old. Translocation as a management technique for mountain lions is ulations at viable levels in a majority of western states (Logan and notwidelyimplemented,butmaybecomeincreasinglyimportantasa Sweanor1999). result of changing attitudes toward predator control (Hancock 1980) Conservationofmountainlionshasalongandvariedhistory,and andlossorfragmentationofhabitat(NowellandJackson1996). hasbeencouchedlargelyintermsofpoliticalexpediency(Torres1997). Effortstocontroloreliminatetheseobligatecarnivoresbyunrestricted Conservation. Conservationofalargecarnivorethatpreysonother harvestandbountysystemswereunsuccessfulthroughoutmuchofthe largemammals,frequentlyisinvolvedinthekillingofdomesticlive- United States, but their efficacy has been attested to by the absence stock,andoccasionallyisathreattohumansafetypresentschallenges ofmountainlionsfrommuchoftheirhistoricalrange.Inthoseareas, thatseemoverwhelmingincontemporarytimes.Theprimarypreyof suchaswesternNorthAmerica,wherelargetractsofessentialhabitat mountainlionsrequirelargetractsofopenandundevelopedland,both remained in relatively pristine conditions, intensive methods of con- ofwhicharebecomingincreasinglyuncommon.Mountainlionsthem- trolling mountain lions gave way to regulated sport hunting, with an selves similarly depend on large tracts of land to meet their needs. emphasisonensuringviablepopulationswiththecapabilityofmain- Indeed,theconservationandmanagementchallengeforthefuturewill tainingasustainableharvest.Selectiveremovalofindividuallionsthat betoassurethepresenceofmountainlionsandtheirprey,despitethe have preyed on livestock or domestic animals has been compatible certain loss of habitat and increases in human numbers and activity throughoutmuchoftherangeofmountainlionsduringtherecentpast. (Torres1997). Eliminationoflionsinvolvedwithhumansafetyincidentslargelyhas InwesternNorthAmerica,mountainlionpopulationsgenerally achievedpublicacceptance. remain healthy (Hornocker 1992), but conservationists will be faced withthetaskofmaintaininglarge,contiguoustractsofsuitablehabi- RESEARCHNEEDS tatthatarelinkedtoothersuchareas.Populationsofmountainlions mayoccurinametapopulationstructure(Sweanoretal.2000;but,see Mountain lions occur at low densities and are secretive and cryptic; Ernestetal.2003).Islandsofhabitatsuitableforsupportingpermanent thus,theyareamongthemostdifficultlargemammalstostudy.Fur- populationssometimesareseparatedbyvastareasofhabitatthatarenot thermore,costsofresearchassociatedwiththestudyoflargecarnivores permanentlyoccupied,butinsteadprovideopportunitiesformovement aregreat,confoundingeffortstoobtainmeaningfulanswerstodifficult between habitat islands. Thus, habitat fragmentation is a major con- questions. Although many aspects of the ecology of mountain lions cern.Beier(1993)andBeieretal.(1995)describedasituationwhere havebeeninvestigated,fewauthorshaveconductedthelong-termin- mountain lion habitat in the Santa Ana Mountains of southern Cali- vestigationsnecessarytobegintounderstandtherelationshipsamong forniahadbecomeisolatedfromothersuitableareasandimmigration habitat, prey densities, and the dynamics of the populations of these likelywasreducedasaresultofhumandevelopment.Immigrationand secretivepredatorsandtheirprey. emigrationofindividualsarenecessaryforthemaintenanceofgenetic Mountainlionshavebeenimplicatedasfactorsimportantinthe diversity.Further,opportunitiesforrecolonizationmustbeprovidedin dynamicsofsomepopulationsofmountainsheep(Kamleretal.2002), theeventofextirpationsfromislandsofsuitablehabitat.Maintaining includingtwopopulationsegments(Wehausen1996;Hayesetal.2000) adequatespaceformountainlionsandtheirpreyaswellaslinkages listedasendangeredbythefederalgovernment.Impactsoflionpreda- betweensuchareasclearlyisapressingissuethatmustbeaddressedif tiononmountainsheeppopulationsaremostprobablewheremuledeer mountainlionsaretoretaintheircurrentstatus. andmountainsheepoccursympatrically(Schaeferetal.2000;Kamler Depredationsonlivestockandotherdomesticanimalslikelywill etal.2002).Nonetheless,clearlinkagesamongthedynamicsofpop- increase in frequency, especially as the human population expands ulationsofprimaryprey(muledeer),mountainlions,andsecondary (Torres1997).Depredationmaybecoincidentwithincreasesinlion prey (mountain sheep) are yet to be established, and warrant serious populations(Torresetal.1996),butmayalsobeafunctionofdeclines investigation. Such investigations must, however, be conducted over inpopulationsofprimaryprey(Pierceetal.1999a,Kamleretal.2002). atemporalscaleadequatetoelucidatechangesinhabitatqualityand Whateverthecause,managementofdepredatingmountainlionswill resultantresponsesamongpreyandpredatorsinsuchsystems(Pierce remainanimportantissue.Currentmanagementofdepredatingindivid- 1999). As a result, population modeling may become an even more ualsusuallyinvolveskillingoftheoffendinganimal,astrategyunlikely usefulpredictivetool,(Beier1993)withmorepotentialforapplication to change in the immediate future. Even in densely populated areas, thancurrentlyrecognized. sucheventsarerelativelyuncommon(Torres2000),andsuchremovals Thegeneticstructureofpopulationsofmountainlionshasbeen likelydonotpresentathreattoexistingpopulationsofmountainlions. examined only recently (Walker et al. 2000; Ernest et al. 2003), and Mountainlionpopulationsapparentlyhaveexpandedduringre- additionalopportunitiestodefinepopulationsfromageneticperspec- centyears,andtherehasbeenincreasingconcernaboutthepotentialfor tiveareneeded.Furthermore,thespatialstructureoflionpopulations anincreaseinhumanencounters.Indeed,suchconcernshaveresultedin hasbeenreportedonlyonalocalscale(Germaineetal.2000;Sweanor publicationofpamphletsandbooks(Torres1997)designedtominimize etal.2000),andlandscape-leveleffortstomoreclearlydefinepopula- theprobabilityofsuchincidents.Youngmountainlions,dispersingbe- tionsofmountainlionsclearlyarewarranted.Moreover,thepotential tweenareasofsuitablehabitat,maybemostapttoencounterhumans; metapopulationstructure(Sweanoretal.2000)ofmountainlionswar- indeed,themajorityofattacksonhumanshaveinvolvedsubadultorap- rantsfurtherinvestigation,andhasimportantimplicationsforthecon- parentlyunderweightlions(Aune1991;Beier1991).Ashumanpopu- servationoftheselargefelids(Ernestetal.2003).GPStechnologycan lationsincreaseandexpandintocurrentlyoccupiedlionhabitat,therate be incorporated into telemetry collars for investigations of mountain atwhichsuchencountersoccurmaybeexpectedtoincrease.Meeting lion movements and habitat selection (Bleich et al. 2000; Anderson human safety objectives while simultaneously providing habitat for and Lindzey 2003) and can be combined with sophisticated genetic
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