Aprobable Case of Twins in the Short-beaked Echidna Tachyglossus Aculeatus (Tachyglossidae: Monotremata), with Observations on Suckling of Young After Their Emergence from the Nursery Burrow

2007·2.9 MB·English

5
Contributions
A
probable case oftwins in the Short-beaked Echidna
Tachyglossus aculeatus (Tachyglossidae: Monotremata), with
observations on suckling ofyoung after their
emergence from the nursery burrow
Frank Pierce', Janet Mattiske' and PeterMenkhorsF
' Box 121,KangarooGround.Victoria,3097;email:[email protected]
-DepartmentofSustainabilityandEnvironment,POBox500,EastMelbourne,Victoria3002
Abstract
The finding ofthe nursery burrow ofa Short-beaked Echidna close to the house ofthe two senior
authorsallowedcloseobservation and monitoringofbreedingbehaviour. Twoyoungemerged from
the nursery burrow eight days apart. Individual colour-marking ofthe mother and both young
allowedtheirmovementsandbehaviourtobemonitoredoversubsequentmonths. Dataarepresented
on post-emergence suckling ofboth young, which continued for 60 days after emergence, and
included one instance when both were suckled simultaneously. Information is also presented on the
movements, survival, and selection ofshelter-sites by thejuveniles. The twojuveniles are likely to
betwins, thoughtheyarenot identical twins. Theseobservationsprovidethefirstrecordofafemale
echidna successfully raising more than one young in a single breeding season, and the firstrecords
ofparental care ofyoung echidnas after they have vacated the nursery burrow. (The Victorian
Naluralisi124(6),2007,332-340)
Introduction
The Short-beaked Echidna Tachyglossus (Griffiths 1978; Augee and Gooden 1993;
aculeatus, along with the Platypus Rismiller 1999; Augee et al. 2006). In
Ornithotynchus anatimis and New Guinea south-eastern Australia, courtship and mat-
Long-beaked EchidnasZaglossus spp, com- ing occurs from roughly mid-June to the
prise the egg-laying mammals (Subclass end ofJuly. Gestation takes 23 days, incu-
Prototheria, Order Monotremata). Echidnas bation ofthe egg in the pouch 9-1 1 days,
differfrom all othermammals by layingan and the young remains in the pouch for a
egg directly into apouch on theirabdomen further 45-55 days (Rismiller and
where it is incubated and the young hatch- McKelevy 2000), The young is then
es. (Platypuses haveno pouch and laytheir deposited in a nurseryburrow, the entrance
two eggs directly into a nest in the nursery of which is plugged with soil after each
burrow). The hatchling, which resembles a visit. Here it remains for 115-170 days
new-born marsupial in its state ofdevelop- until emergence. Thus the period from
ment, develops in the pouch until it is conception to emergence is 6.5-8.
capable ofbeing left in a burrow while the months. Females rarely breed annually
mother forages. Young echidnas feed by (Augee et al. 2006) and in a study on
sucking milk from one of two areolae Kangaroo Island, South Australia, observa-
located inside the pouch - there are no tion oftagged individuals indicated that
teats. Observations of the frequency of a females bred on average only once every
mother’s visits to the nursery buiTow indi- 4-6 years (Rismiller and McKelevy 2000),
cate that suckling occurs at intervals of avery lowrate ofreproduction.
several days (Griffiths 1978, Augee and There are very few records ofmore than
Gooden 1993). However, the milk is rich a single egg being laidby the Short-beaked
in fats (Griffiths 1978) and a young can Echidna. Griffiths (1978, page 245) lists
imbibe up to 40% ofits body weight in a one instance oftwo eggs being found in a
single feeding session lasting up to one pouch and another of two pouch young.
hour(Rismiller 1999). Augee and Gooden (1993, page 31) state
The Short-beaked Echidna is the most that ‘twins are known to occur rarely’
widespread ofAustralia’s native mammals without giving further details. Augee etal.
but, until recently, comparatively little was (2006, page 82) statethat ‘usuallyonly one
known of its biology and ecology egg is impregnated at a time, it is rare to
332 TheVictorian Naturalist
Contributions
find a female carrying two young in her year cycle ofpatch raking or cool burning,
pouch.’ Further,thereappearto beno docu- so that in any year only 20% ofthe area is
mented cases of female Short-beaked fuel reduced. Fallen timber, that is not fine
Echidnasraisingto independencemorethan fuel, is retained. All plants are indigenous
one young per breeding season. Here we except in the kitchen garden and some pot-
describe observations of an individually tedplants and ferns underthe verandah.
recognisable female Short-beaked Echidna Echidnas are not considered uncommon
that was suckling two young that had in the area. They are seen frequently in the
emerged from the same nursery burrow summer when they come to drink and
eight days apart. We also provide the first bathe in the garden ponds, particularly on
documented observations ofmaternal suck- veryhotdays.
ling ofyoung long after their emergence
from the nursery burrow, and movement ITdheentimfoictahteironaonfdinfdoiuvriduoatlhser adults that
ptahtetyerinnscraenasdedbethheaivriohuormeofrathnegeysoaunndgcuonutlidl viidseintteidfideudribnyg dtehteaiolbesdervaantailoynsisperoifoddiwgietrael
befoundonlyintermittently. photos of the spines in their tails. The
Methods mother had a broken spine on the lower
Descriptionofstudyarea right side which facilitated her identifica-
The observationsoccurred in and aroundthe tion (Fig. 1), butthe variation in shape, size
garden ofFP and JM atthe Bend ofIslands, and colouring ofthe individual tail spines
a 400 ha area ofhigh conservation-value made identification ofeach echidna quite
bushland, located adjacent to the Yarra feasible. The two juveniles were easy to
River, 33 km north-east ofMelbourne. The identify due to differing size, spine density
area is zoned Special Use - Environmental andcolourofspinesandfur(Fig. 2).
Living under the Shire of Nillumbik We initially marked the juveniles with
Planning Scheme. This zoning prohibits the paint on opposite sides oftheir tails. Later,
keeping ofdogs, cats or other domestic or small ringswere made from the plastic insu-
farm animals, restricts the planting ofnon- lation on electrical wire and three ofthese
indigenous plants to a contained kitchen were glued to spines on the back, different
garden area near each house and prohibits sides and colours being selected for each
the removal ofnative vegetation without a individual (Fig.2).Thejuveniles,themother
permit. The house is located on the Round and one adult, ofsimilar size and colour to
the Bend Conservation Cooperative, a 128 themother,weremarkedinthisway.
ha property owned by 32 shareholders each
Recording
with a 0.15 ha house site strategically locat- To facilitate recording and communication
edtominimise impact. each echidna was given a reference. The
The vegetation is Box-lronbark woodland juveniles were B1 and B2, mother was M
with an understorey ofnative herbs, grasses andothervisitingadultswereA1 to A4.
and sparse shrubs. The dominant eucalypt Initially, after the burrow had been
species are Red Ironbark Eucalyptus noticed, photos were taken of the back-
saindderRoexdylSutnr.inLgoynbga-rlkeEa.fmBaocxroEr.hygnocnhiao.caTlhyex filled surface at the entry each time it
house is surrounded by a verandah and by cbhyanthgeedm,otthoerre.coWrhdetnheBo1ccwuarrsenfcoeunodfbveisiintgs
brick paving extending to a terraced-fill gar- suckled outside the burrow, photo and
edaesnt.toAthfeenwceesdtatrnadnsapitreartriaocne-bcuetd/gkairtdcehnentogtahre- vmiednetos cwleirperemcoonridtsorweedrefaitralkyecnasaunadllmyoovvee-r
den,garage,woodshed,gardenshedandwater the next week. When B2 was found being
tanks are located to the north ofthe house. suckled outside the burrow, eight days
Thhouesreesaraereno70femncteostihnethneoratrheaanadnmd70themnetaoretshte aafltseortBalk,enp.hoTtoheansdigvniidfeiocaclnicperoecfomrdusltwieprlee
east. The nursery burrow was 4 north-west young was then established and move-
ofthehouseattheendofaterracedgardenbed. ments and behaviourwere monitored more
The bush area adjacent to the house has
closely by FP and JM.
the ground fuel reduced for fire protection.
This is carried out sensitively on a five
Vol. 123 (6) 2006 333
Contributions
Fig. 1. M sucklingBl atitsemergencefromthenurseryburrow,30December2005.NoteM’sdiag-
nosticbrokentailspine.
Monitoringgenerallyinvolvedperiodically Thefollowingrecords' were kept:
checking the location and activity ofthe • Record Summary Sheet - A tabulated
M
juveniles. The frequency ofobservations record ofvisitsby orotheradults and,
depended on the activitylevels ofthe echid- when possible, the overnight shelter
nas, and our time availability. Typically we location, duration of activity period for
would go out about every hour or so and the day, distance travelled for the day
find Bl and B2 ifpossible, recording loca- and the night shelter for each ofBl and
tion and activity and always keeping an eye B2, andnotes ontemperature, if33“C or
M
out for or other adults. The difficulty of higher, and anynotableactivities.
finding the juveniles increased as they • Daily Routes Plan - A separate A4 plan
developed and became more mobile, far- of the house and surrounds was used
ranging, and adept at hiding. Recording each day to record the location and time
comprehensive daily route infonnation gen- of each echidna whenever seen. The
erally became impractical afterthe first four daily route was then plotted for Bl, B2
M
orfiveweeks. and or other adults, if sufficient data
Detection in the bush was much harder had beencollected.
than in the immediate house sun'ounds. The • Detailed Notes - A detailed account of
best detection method developed for the significant events, if aiiy, was kept in
bush was to remain motionless for at least dailydiary format.
five minutes and listen formovement ofthe • Digital photos and video clips were taken
ground litter. Ifnoresult,thenmove20mor with a Canon Powershot SI-IS xlO opti-
soandstartagain.Temperaturewasrecorded calzoomcamera. The photonumber, date
by a thermometer on the north wall ofthe andtimewereautomaticallyrecorded.
house, under a 2,5 m wide verandah.
MinimalInterference
Observations continued until thejuveniles
dispersed from the vicinity ofthe house in Our aim was to minimize interference to
February. Intermittent observations were the echidnas, to enable observation ofnat-
recordeduntil late March. ural, unaffected behaviour. The echidnas
were not handled except to attach the
334 The Victorian Naturalist
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Contributions
marking rings. The juveniles were left to in the adjacentgarden and excavatingthree
their own devices except that bowls of small sheltersites.
waterwere putouton daysofextreme heat On 7 January2006, B2 was found suckling
and an old door was used to provide shel- from M next to the nursery burrow at 1300
ter from sun or rain in two extreme hrs. B1 was about4 m awayinasmall exca-
circumstances. vated shelter at the base ofa sleeper wall.
The main entry to the burrow had not been
Results excavated (the surface was identical in pho-
Chronologicalsummaryofobservations tos taken on 5 January and later on 7
ThenurserybuiTow was firstfound in early January). B2 had emerged from the nursery
November 2005. Photographic records of burrow via a small opening in the uppersur-
changes to the earthen plug at the burrow face at the south end ofthe buiTOw (Fig. 3).
entrance indicate a visitation frequency of This opening had notbeen noticed previous-
4-5 days. At least two visits to the burrow ly; however, asubsequentblowup ofaphoto
by the mother took place in the evening. takenon 5 January indicatesthattheopening
Opening ofthe burrow entrance took up to may have been partially open at that time.
one hour. While suckling was taking place There had been disturbance at the opening
a distinctive ‘snuffley heavy breathing’ surface subsequent to 5 January, and when
could be heard from within the burrow. investigated on 7 January, it was found to
This sound was later heard at observed provide narrow but clear access to the bur-
sucklingeventsoutsidetheburrow. row. The opening could accommodate a
On 30 DecemberM2005, Bl was found juvenile the size of B2 but not an adult. M
being suckled by immediately outside had been observed towalk overthisopening
the closed burrow entrance at around mid- at 1200hrswhenapproachingtheburrow. M
day. Bl remained outside the burrow lefttheareaat 1430hrsand B2 movedabout
entrance all afternoon and was in the same until settling in an excavated shelter that B1
olofchaitgiohnttehmepefroaltluorewsin(gupmotroni4n2g°.C)Beacnauosled thhaedirprseevpiaoruastleymsahdelet.erBs1oavnedrBt2herefmoalilnoewdinign
wooden door was positioned above Bl’s threedays,graduallyenlargingthem.
usual resting site to provide shade on 3 On January, following overnight rain,
rDeemcaeimnbeedr.witAhsinf4armasofcothueldbubrerosweefno,r tBhle aBb1ouwta12s15fmoumndofinwaittsers,heclotledr oannditsshibvaecrkingi.n
next week, making only short excursions
Fig. 2. The two iuvenilcs showing the variation in size, fur colour and the colour and density of
spines. Left: Bl withredplasticmarkers. Right: B2withgrcen/yellow markers,22 February2006.
Vol. 123 (6) 2006 335
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Contributions
Fig.3.Thenurseryburrowafterexcavationoftheroofand loosematerial,29March2006.
The shelterwas drained, dry mulch provid- B2 spent most ofthe following 10 nights
ed and the old door was placed on the ter- in the garden shed, while B1 continued to
race level above toprotectthe shelter. That use adifferentsheltersiteeachnight. On23
afternoon B1 moved about considerably, January, M was observed systematically
making three determined efforts to climb a checking the shelter locations used by B1
0.4 m high section of sleeper wall before and B2 on herpreviousvisits. Shethenpro-
finally succeeding and entering the shelter ceeded verydeliberatelytothegarden shed,
occupied by B2 (initially excavated by B1 as iffollowing a scenttrail, and suckled B2
between 2 and 5 January). They both but not Bl, although it was foraging within
stayed together in this shelter for the fol- 3 m ofthe shedentrance. Subsequentobser-
lowingthree nights. vationsofsucklingare listedinTable 1
Each morning they ventured out together From early February 2006, bothjuveniles
to bask in the morning sun (see front movedincreasingdistances fromthegarden.
cover), then movedoffindependently, trav- Between 15 and 20 February, Bl was seen
elling further each day. B2 returned to the only once - 60 m from the house - and B2
same sheltereach night, whereas B1 used a wasseenononlyfiveof13 daysbetween 1
different shelter site every night, including Februaryand 2 March. B1 then returnedand
one night beneath tussocks (Silvertop stayed in the vicinity ofthe garden between
Wallaby-grass Joycea pallida and Small 21 and 28 February when it was suckled
Grass-treeXanthorrhoeaminorssp Intea). twice (Table 1). B2 spent long periods (24-
On the night of 18 January, B1 and B2 48 hr) inactive in a shelter on 7 March. 12-
shared a new shelter site under the old door. 13 March and 17-18 March, suggestive of
M
At 1000 h on 19 January 2006, was found having been suckled just prior to these
at the shared shelter site suckling bothjuve- times. The last sightings ofthe echidnas
niles simultaneously, 20 and 13 days respec- prior to the 2006 winter and the first sight-
tively afterB1 and B2 had emerged fromthe ingsin springaresummarisedinTable2.
M
nursery burrow. was standing tall on her Subsequently, neighbours reported several
front legs, with her forefeet turned outwards, independent sightings of Bl and B2 at a
her back arched, and her head between her location 1200 m west ofthe house. Most
frontlegs,possiblyforaddedsupport. B1 was visits near the house occurred on hot days
lying on its right side perpendicular to M’s and included a drink and swim in the
rightside,withitsheadbetweenM’sfrontand ground level 'birdpond’.
rear right legs and well under M’s body to
accesstheareola. B2was inasimilarposition Observations ofsucklingafter emergence
oinngMt’hesrlheyftthsmidiec.mBoovtehmBe1ntasnadndB2sowuenrdesmasasko-- frSoumcktlhiengnuarfsteerryebmuerrrgoewnce was observed
ciatedMwith suckling. This was the first sight- oinnvo1l0veodccBalsiaolnosne,(T5abBl2e a1l)o.neF,ouarndofBlthaensde
ingof sinceB2hademergedon7January.
336 TheVictorian Naturalist
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Table 1. Summary ofobservations ofsuckling by the twojuvenile echidnas Bl and B2 afteremer-
gencefromthenurseryburrow,d=days.
Date Timeofday Juvenile Subsequentactivityofjuvenile
30 Dec2005 1200 Bl on firstemergence Stayedoutsidenurseryburrowfor3 d
7.Ian 2006 1300 B2on firstemergence Stayedclosetonurseryburrow for5 d
19Jan2006 1000 B1 andB2 Lowlevel ofactivityfornextfewd
23Jan2006 1200 B2 Probablvinactivefornext2d
30Jan2006 1500 Bl Lowactivity level fornextfewd
7 Feb2006 1842 B2 Lowactivitylevel fornext2-3 d
17Feb2006 1340 B2 Littleactivityfornext2d
2218 FFeebb22000066 11144152 BBll TPrraovbealblleydi5n0acmtivtehefnorpnreoxbtab1l.y5ldow
activityfor2d
3 March2006 1336 B2 Travelled 100mthenprobablylow
activityfor4d
Table 2. Dates oflast sightings before winter 2006 and first sightings the following spring for the
markedechidnas.
Echidna Lastsightingbeforewinter Firstsightingafterwinter
M 31 March,400mwofhouse 19August, firstechidnaseennearhouse
BI 19March,nearhouse 18September, 60mswofhouse
B2 23 March,nearhouse 19September, nearhouse
A4 21 March, lastadultseennearhouse
B2 were fed simultaneously on one occa- for about 20 minutes from one side before
sion. On one visit M Fed neither young, switching to the other side, presumably to
and once she was seen leaving the area, so access the other areola (Fig. 4). When feed-
it is not known whether she fed either ing, the mother demonstrated a strong
juvenile. The sequence ofobserved feed- maternal instinct and tenderness towards the
ing events, showing the interval (in days), juvenile. After feeding was finished, M
and thejuvenile concerned, was: B1-8-B2- would typically rest for about 15 minutes
12-B1&B2-4 B2-7-B1-8-B2-7-7-3 B2 4- and then move offand almost immediately
B1-7-BI-3-B2. For Bl, the intervals commence foragingas shewent. Afterfeed-
between observed sucklingevents were20, ing, thejuvenile was sometimes active; on
1 1, 22 and 7 days; for B2 12, 4, 15. 10 and other occasions it would move to a shelter
14 days (Table 1). The period from bur- andrestforuptotwodays.
row emergence to the last observed suck-
ling was 60 days for Bl and 55 days for VisitshyOtherAdults
B2. At least four adults (apart from M) visited
the garden during the observation period.
SMucklingBehaviour A4 was identified on 6 visits, A3 on 1, A2
would sometimes spend a long time for- on 1 and A1 on 2. There were also 4 adult
aging in the bush around the house before, visits where no photos were taken and
apparently, actively seeking out ajuvenile identification was not possible. The only
M
to feed. For example, on 21 February interaction observed between these adults
browsed for 2'A hours, including bathing and the juveniles was when Bl sniffed
twice, before feeding Bl. However, once around one of the unidentified adults for
started, her search for the juvenile was about 15 minutes while the adult remained
focused - M would systematically check motionless. Bl then movedoff
locationsw'here Bl and B2 had beenonpre-
vious visits and then proceed very purpose- Comparison ofthejuveniles
fullyasifshewasfollowingascenttrail. The juveniles were certainly not identical
On approach, thejuvenile would usually twins. B2 had blacker furand more numer-
freeze and M w'ould prod it with her snout ous, longer spines that were whitish with
until it seemed to smell the milk and move dark tips. Bl was smaller, had browner fur
tostartto feed. Nomially, theyoung suckled and less dense, shorter spines that were
Vol. 123 (6) 2006 337
Contributions
buffwith dark brown tips (Fig. 2). Bl’s They were often inactive until late in the
colouringwas similarto M’s. When Bl left morning, emerging from the overnight
the burrow on 30 December 2005 it was shelter at around 1 130 h EST (daylight
significantly less developed than B2 was saving). The first activity was usually a
when itleftthebuiTow on 7 January2006. sun-bath for 10 to 15 minutes (front
Bothjuveniles grew significantly overthe cover). The periodofactiveforaging, often
period from emergence to dispersal. At interspersed with a sleep under some
emergence Bl was approximately 40% of cover, varied from 0 to 8 hours per day. It
M
the lengthof and B2 was slightly bigger. wasnotunusual for them toremain in their
At dispersal Bl and B2 were both approxi- overnight shelter all day. B2 remained in
mately 65% ofthe length ofM. When first its shelter for more than 48 hours on at
seen after winter, in September 2006, Bl leasttwooccasions.
and B2 appeared to be a similar size to The selection ofovernightshelter seemed
when they were last seen in March, indicat- at times to be entirely random, yet at other
ing that no significant growth occurred times a location was used repeatedly over
overthewinterhibernationperiod. consecutive nights and sometimes re-used
at another time. A wide variety of loca-
Activitiesofthejuveniles tions were used, ranging from a clump of
The juveniles appeared to instinctively grass in the bush to being hidden under
start digging and foraging from the day equipment in the garden shed. On several
they left the burrow. They were capable occasions, existing holes in the ground,
climbers and actively curious. Their made by other animals, were used. At
activities were highly unpredictable and other times they excavated their own hole
apparently spontaneous. For example, B2 under a log or other cover. On 16 March,
spentseveraldaysdiggingasheltertoadepth B2 was foraging when heavy rain began
of550mm; itthenleftanddidnotre-useit. falling. It moved directly to a tree, 8 m
Fig.4. M sucklingB2on 17February2006,41 daysafteremergence fromthenurseryburrow.
338 The Victorian Naturalist
Contributions
away, which was hollow at ground level, base ofthe excavation. There were several
and buried itself in the litter within the side pockets with higher base levels that
trunk where it was quite dry. It stayed were perhaps used as rest chambers. The
thOerne foonrethoecnceaxstio4n0,hoausrsB.1 was walking texuintnealt1t2h0emsomutwhideendbywa9s0 macmceshsigehd lbeyad-a
along the top ofa 1 m high sleeper retain- ing to a large shallow area where the sur-
ing wall, it appeared to be using the crural facehad collapsed underthecoverplates.
spur near its hindfoot to stabilise itself Given the activity levels ofthejuveniles
whilepeeringdown thewall face. immediately after their emergence, it is
likely that they would have been actively
Interaction ofthejuveniles digging in the burrow, perhaps explaining
B1 and B2 were quite independent ofeach the surface cave-ins, loose material on the
other. When they were together their rela- floor and the eventual construction of the
tionship could be described as passive toler- upperexitusedby B2.
ance. There was little evidence ofinteractive No post-emergence use ofthe burrow was
playsotypicalofmanybaby mammals. This observedexceptthat B2 spentashorttimeat
was surprising, given theiractive, inquisitive the upper exit one very hot day when it
characters, but reinforces our knowledge of appearedtobesufferingfrom theheat. After
the solitary nature ofthe echidna. Similar the steel cover plate was slid to the east to
passive tolerance has been observed enlarge the gap from the top ofthe adjacent
between adults on occasions when they sleeper. B2 only partially entered the exit,
havesimultaneously usedthegarden pond. although there was clear access into the
NurseryBurrow burrowwhereitwouldhavebeen cool.
mm
The burrow was located behind a 460 Discussion
highsleeperwallthatretainedtMheupperlevel PossibilityofAdoption
ofa 3-level terraced garden. entered by Although wehave no reason tobelieveoth-
digging under the sleeper wall from the 2"^ erwise, we were unable to prove that the
level. The gravel surface above the burrow twojuveniles were siblings- DNA primers
was level with the top ofthe sleepers and were notavailableto allow identification of
formed a hard crust. However, there were a parents in the Short-beaked Echidna (D.
number of small cave-ins where holes Middleton, Healesville Sanctuary, and P.
formedinthesurface. On 18 December2005 Rismiller pers comm.). Therefore we can-
ajuvenileechidnacouldbeseen belowasur- not discount the possibility that one ofthe
face opening. A sheet ofchipboard was babies was adopted by the mother, perhaps
placedovertheopening.Thecoveringhadto afterhaving been dislodged from thepouch
be extended a numberoftimes as new cave- ofanotherfemale, orbeing found in anear-
ins occurred. By 28 December the covering by nursery burrow. Cases ofadoption of
had been upgraded to an area of 1 m by 1.5 pouch young are known to occur in marsu-
m. with a steel plate covering another small pials, including macropods and bandicoots
cave-in through which ajuvenile was seen (Gemmel 1988) butwould seem unlikely in
on 23 December 2005.mTmhe upper exit was a solitary animal such as the Short-beaked
later formed at the 50 gap between this Echidna. Regardless, our observations rep-
plate and the top ofthe sleeper wall. These resent the first record of a female Short-
observations indicate that the upperexit was beaked Echidna raising more than one
constructedfrom insidetheburrow. youngperbreedingseason.
The burrow was excavated and measured
on 28 March 2006 after the juveniles had Patternsinsucklingwithintheburrow
dispersed (Fig. 3). The burrow consisted of The frequency ofM’s visits to the burrow
a main curved chamber, 1.5 m long by (every fourto fivedays), as estimated from
300-800 mm wide. The effective clear observed changes in the soil plug at the
height was 200 mm from the underside of burrow entrance, are consistent with pub-
the roofto the surface ofthe loose material lished data on suckling rates ofbetween 3
on the lloor. The depth ofthis loose mater- and 6 days (Griffiths 1989; Rismiller and
ial varied from 0 to 160 mm and was easily McKelvey 2000), despite the fact that she
removed with a gloved hand to expose the was presumably suckling two rather than
Vol. 123 (6) 2006 339
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Contributions
one young. Whether this delayed develop- selecting inadequate shelter sites during
ment ofthe young is not clear but it does rainy weather. However, asthey developed,
not seem to have had a major effect as they seemed to learn to find dry shelters
their stages of development at emergence duringrain,asobservedon 16March.
fall within the documented range and both
Activityperiods
ssuurgvgievsetditnhgeirthfaitrsttyheeairronuotusirdiesthhmeebnutrrwoaws, B1 and B2 were active formuch ofthe day,
except for early morning. They seemed to
adequate.
wait until the sun was high and then often
Patternsinsucklingafterburrowexit sunned themselves, sometimes on a paved
These observations represent the first doc- surface before beginning to forage.
umentation ofcontinuing maternal care in Although nocturnal monitoring was limited
the Short-beaked Echidna after the young to searching on only a few nights, we
has left the nursery burrow. All other formedthe impression that B1 and B2 were
authors state that the young is abandoned mostlystationaryatnight. B1 wasfoundina
by the mother once it has been suckled differentshelterinthemorningontwoocca-
immediately after first emergence sions and we do not know the timing of
(Griffiths 1989, Augee and Gooden 1993, these movements - they could have
Rismiller 1999, Augee et al. 2006). occurred at orjust after dusk, after we had
However, our observations indicate that assumedithadsettledforthenight,oratany
suckling can continue for up to 60 days othertimebeforeourfirstmorningcheck.
aftertheyoung leavesthenurseryburrow. The opportunity to monitor the echidnas
There was no obvious pattern in the so close to the house is testament to the
length of intervals between the observed success of the local planning provisions
feeding events, which ranged from 4 to 22 that prohibit domestic pets and aim to
days, but they were considerably longer maintain and advance the environmental
than the four to five day intervals recorded integrityofthearea.
during the nursery burrow stage. It is Acknowledgements
aolcmcousrtrecderutnaionbstehartveodthe~rMfeecdoiunlgdemveonvtes WenecotuhraangkemPeengtgdyurRiinsgmitlhleeorbsfeorrvahteironadpveircieod.and
quickly and was amazingly cryptic. It
Note
would be reasonable to assume a detection ' Detailed records ofourobservations, includingpho-
rate in theorderof50%. tos and videos ofmost suckling events, and a geo-
metricPlanandSectionofthenurseryburrowcanbe
Inclementweather madeavailableuponrequest.
As echidnas have a normal body temper-
References
ature of 33° C and do not sweat or pant, Augee M andGooden B (1993)EchidnasofAustralia
they are vulnerableto heatstress (Augee et andNew Guinea. (University ofNew South Wales
al. 2006). The juveniles seemed to cope AuPgreeses:MS,ydGnoeoyd)en B and Musser A (2006) Echidna:
well on hot days. B1 was initially suckled Extraordinary egg laying mammal. (CSIRO
outside the burrow in 39° C heat. For the Publishing:Melbourne)
rest of that day and the following day, GcpmomueclhRoTf(t1h9e88)baAndciocmopoots,iteLsliototedroonfymoaucnrgotiinntihse
when ambient temperature reached 42° C, (Marsupialia: Peramelidae). Australian Mammalogy
cBo1mprleemtaeilnyedbuoruitesdidine tthhee sbuurrfraocew saoliml.osAt Gri(IftAf,ciat1dh5se7m-M1i5c8(.P1r9es7s8:)NTehweYBoirokl)ogy ofthe Monotremes.
doorwasplacedtoprovide shade forB1 Griffiths M (1989) Tachyglossidae. In Fauna of
B2 seemed to be heat stressed on 26 AWuasltrtaolniaDVWoluamnedlbR.iMcahmamradlsioan,BpJp.4(0A7u-s4t35r.alEidans
January2006. Itwas 39°C lateinthe after- GovernmentPublishingService:Canberra)
noon when B2 partially entered the upper RismillerP (1999) TheEchidna: Australia’s Enigma.
ecxoiotlocfhtahnegneurasrerriyvebdu.rrWoew.pFloarcteundatwealtyera Ri(bsmHriuelgelhdeirLnaPguDtaearnndLderMveiccnKreAulsisvtoemcyieanMtteWsinIn(ct2.h0)e00)ShForretq-ubenecaykeodf
bowls near B1 and B2 on very hot days. Echidna, Tachyglossus aciileatus. Journal of
They drank some water but B1 wanted to Mammalogy81, 1-17.
climb into the bowl and B2 typicallytipped
iBt1s baonwdlBov2erw.eOrne aftoulenadstcoonldeoacncdaswieotnabfottehr Received8March2007;accepted9August2007
340 The Victorian Naturalist