Observations of cannibalism and prey records in the Dugite or Spotted Brown Snake (Pseudonaja affinis affinis)

2005·0.88 MB·English

by  Brad Maryan

OBSERVATIONS OF CANNIBALISM AND PREY
RECORDS IN THE DUGITE OR SPOTTED BROWN
SNAKE (PSEUDONAJA AFFINIS AFFINIS)
By BRAD MARYAN
169 Egina Street, Mount Hawthorn WA 6016
and GLEN GAIKHORST
6 Flemming Court, Forrestdale WA 6112
True cannibalism in snakes On 4 October 2004, BM received
whereby a species actively a phone call in the afternoon
subdues and swallows a from a resident in Wanneroo
conspecific is rarely observed in (31945' S, 115e48’ E) that an adult P.
the wild. It is usually an artefact affinis was subduing another
of confinement in captivity snake and attempting to swallow
where accidental predation is it in their front garden. The
commonly observed and identification of the snake being
documented for captive snakes consumed was unknown to the
(Hoser 1993). Greer 1997 provides residents. Upon BM’s arrival ca 30
an overview of true cannibalism minutes later, the unidentified
in Australian elapids that snake was determined as another
includes only a single species of P. affinis, which was by this time
brown snake, the Eastern Brown almost completely swallowed.
Snake, Pseudonaja tcxtilis. Similar The residents informed BM that
to P. textilis, the mainland the commotion from the birds
population of R affinis is a large drew their attention to the
(up to 2 metres) opportunistic writhing snakes, and that the
foraging hunter displaying a initial struggle was the most time
strong predilection for disturbed consuming period lasting up to
habitats such as industrial areas, 40 minutes. Once the aggressor
golf courses, road verges etc. in had subdued the other snake it
close association with agricultural drew it out length wise to
development (Shine 1989). commence swallowing from the
head. The well-vegetated garden
Maryan and Bush (1996) provided
made photography difficult and
a summary of all available
unfortunately the deceased
literature on prey in P. affinis.
snake was regurgitated in the
This note describes two separate
observations of true cannibalism hoop bag after capture. Both
snakes were similarly sized in
in the Perth metropolitan area
length (ca 1.1 metres) and girth,
and additional prey records that
and sexed as males.
include birds, mammals and
other reptiles. The other event occurred on 23
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January 2005 at another items (Maryan and Bush 1996)
residence in Wattle Grove (32B02’ including aviary birds such as
S, 116200' E). A single adult 1.5 quails, mammals such as the
metre P. affinis was observed Southern Brown Bandicoot
active between 2-3pm along a (Isoodon obesulus) and other
corrugated iron fence beside the reptiles like the Bobtail (Tiliqua
driveway. Suddenly it very rugosa), Ornate Dragon
quickly turned in the opposite (Ctenophorus ornatus) and Bardick
direction to pursue and grab (Echiopsis curta). Other birds
another adult dugite of lesser recorded as prey in aviary
size, resulting in a writhing battle situations include canaries,
with multiple bites being budgerigars, and various species
delivered by both snakes. This of small doves, pigeons and
lasted approximately 10 minutes parrots and an incident of a
until the larger individual dugite killing a large pheasant
finally dragged the other snake without making any attempt to
to a more sheltered location to swallow the bird. Many of these
commence consumption (Figure incidents involving birds as prey
1). The sex of the snakes was not items may initially be due to the
determined. attraction of exotic mice in and
Pseudonaja affinis has been around the aviary (Maryan and
opportunistically observed Bush 1996), however the variety
feeding on a wide variety of prey of birds consumed that include
Figure 1. Dugite beginning to swallow another Dugite at Wattle Grove on 23
January 2005. Photo: Zack West.
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swift flying parrots, underlines the turtle was alive when first
the degree of opportunism in a encountered by the snake.
situation where a reptilian The combination of size,
predator can consume trapped foraging habits and abundance
prey. We have observed P. affinis in human disturbed areas of P.
on several occasions unable to affinis ensures this species of
exit or appear to be reluctant to
elapid is regularly sighted in the
leave an aviary due to gorging Perth suburbs. The successful
itself on caged birds. In addition and recent adaptation of P. affinis
to the introduced rodents (House to a highly modified environ¬
Mouse Mus musculus and Rattus ment, the beneficial role it plays
spp.) that constitute the majority in the control of exotic rodents
of prey items recorded in P. affinis and a very generalised diet
(Shine 1989), we have also including its own kind, make
recorded a small European this species an interesting
Rabbit (Oryctolagus cuniculus) biological case study that has
being eaten by an adult dugite been highlighted for its eastern
during a snake removal call. counterpart P. textilis (Whitaker
Chapman (1999) provides details and Shine 2003).
of a P. affinis subduing and
swallowing a Tiger Snake
(Notechis scutatns) with the entire ACKNOWLEDGEMENTS
sequence recorded on colour
We thank fellow herpetologist,
print film. Another incident of a
Linda Gwinett for alerting us to
80cm P. affinis eating a 60cm N. the Wanneroo snakes, and Billy,
scutatus has been observed in the Gary and Zack West for sharing
Darling Range at Wungong Dam
with us their observation in
(32213’ S, 116204' E), however it is
Wattle Grove. Thank you to all
possible that the tiger snake was
those residents who leap for the
a road victim as the observation
phone, rather than the shovel
took place beside a vehicle track
and allow us to make some
and it had a large open body
interesting observations of
wound. The opportunistic
reptiles ‘caught in the act’.
nature of this large elapid is truly
highlighted with an observation
of 150cm male P. affinis REFERENCES
attempting to eat an Oblong
CHAPMAN, A. 1999. Dugite eats
Turtle (Chelodina oblonga) in a Tiger Snake. The Western
horse paddock at Wattle Grove.
Australian Naturalist 22 (3): 209.
The dugite had eaten the head
and neck but obviously the GREER, A.E. 1997. The Biology and
30cm carapace prevented it from Evolution of Australian Snakes.
Surrey Beatty & Sons, Chipping
further consumption eventually
Norton.
resulting in regurgitation after
capture. It is not known whether HOSER, R.T. 1993. Notes on
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feeding interactions in Australian (Pseudonaja: Elapidae).
Reptiles. Herpetofauna 23 (1): 32-35. Herpetologica 45 (2): 195-207.
MARYAN, B. and BUSH. B. 1996. WHITAKER. B.P. and SHINE. R.
The Dugite or Spotted Brown 2003. A radiotelemetric study of
Snake Pseudonaja affinis. movements and shelter-site
Herpetofauna 26 (1): 22-34. selection by free-ranging
SHINE, R. 1989. Constraints, brownsnakes (Pseudonaja textilis,
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habits and reproductive biology Monographs 17:130-144.
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