Varanus gouldii Predatory accounts from the most recent addition of the Herpetological review
"The Western Brown Snake (Pseudonaja mengdeni) is a wideranging venomous snake in central Australia (Wilson and Swan
2017. A Complete Guide to Reptiles of Australia. Reed New
Holland, Sydney, Australia. 585 pp.). At 1100 h on 1 February
2016 one of us (AS) took video of an adult V. gouldii (ca. 0.8 m
TL) preying upon an adult Western Brown Snake (ca. 1.5 m TL)
at the Curtin Springs Station homestead, Northern Territory,
Australia (25.31426°S, 131.75622°E; WGS 84). The snake was caught in a chicken wire fence, ca. 100 cm from its head. The
monitor grabbed, shook, and tore into the anterior two-thirds
of the snake, ca. 20 cm behind the head. The monitor pulled
the trapped snake, eventually killing it, but was not successful
in freeing the snake from the fence. The entire predation event
lasted ca. 12 min.
A second observation of predation of a Western Brown Snake
by V. gouldii was recorded at the same homestead (25.31428°S,
131.75654°E; WGS 84). At 1430 h on 4 November 2018 a station
hand, D. Rowley, discovered an adult V. gouldii (ca. 0.8 m TL)
with a Western Brown Snake (ca. 1.2 m TL) in its mouth, near a
parked vehicle. The lizard seized the snake just behind the head
and shook it vigorously until the snake appeared dead. The
lizard swallowed the snake shortly thereafter. Both species are
abundant at the station (CDG, pers. obs.) and these predation
events are likely common. Snakes have been recorded in the
diets of V. gouldii (Losos and Green 1988, op. cit.; Sutherland
2011, op. cit.), but are seldom identified to species, and Western
Brown Snakes have not been previously been identified as a prey
item of V. gouldii."
"The Yellow-throated Miner (Manoria flavigula) is a common
passerine bird with a distribution across Australia and a bill-tip
to tail-tip of 22–28 cm (Simpson and Day 2010. Field Guide to
the Birds of Australia. Eighth Edition. Penguin Books Australia,
Melbourne, Australia. 198 pp.). At 1001 h on 15 December
2017, a staff member recorded an adult V. gouldii consuming a
fledgling M. flavigula, which it captured on the ground at the
same homestead (25.31471°S, 131.75668°E; WGS 84). The lizard
(0.8 m TL) initially struggled with swallowing the bird’s wings but
succeeded in swallowing the bird in ca. 2.5 min. Birds have been
recorded in the diet of V. gouldii (Losos and Green 1988, op. cit.)
but rarely to species. Manoria flavigula at Curtin Springs seem
aware of the predation risk from V. gouldii as they will readily
make alarm calls in their presence. At 1411 h on 23 December
2017 CDG observed two M. falvigula making alarm calls within a
2-m radius of an adult V. gouldii (25.31485°S, 131.75607°E; WGS
84). The birds moved, perched, and called above the V. gouldii as
the monitor foraged through the garden.
Varanus gouldii are known to consume lizards including other
monitor lizards (Losos and Green 1988, op. cit.; Pianka 1994, op.
cit.; Sutherland 2011, op. cit.). At 1506 h on 3 January 2018, CDG
pulled over to inspect a DOR V. gouldii on the Lasseter Highway
(25.31555°S, 131.76890°E; WGS 84). Closer inspection revealed a
tail dangling out of the monitor’s mouth. The tail belonged to a
juvenile V. gouldii that had apparently been consumed just before
the monitor was struck by a vehicle. The predatory monitor (ca.
0.60 m TL) was much larger than the cannibalized monitor (ca.
20 cm TL). Cannibalism is common in monitor lizards (Pianka
and King 2004. Varanoid Lizards of the World. Indiana University
Press, Bloomington, Indiana. 588 pp.) and has been reported in
V. gouldii twice: Johnson (1976. Zool. J. Linn. Soc. 59:377–380)
reported an adult consuming a juvenile in captivity, and Shine
(1986, op. cit.) found a V. gouldii within the stomach of another
(sizes were not given). Overall our observations of prey items in
central Australia add to our knowledge of the diet of V. gouldii,
but also highlight the importance of predation observations as a
supplement to the examination of stomach contents in museum
specimens."
