Mitchell's monitor is a small arboreal goanna found along
the waterways of northern Western Australia and
Northern Territory. Its long compressed tail led Mertens
( 1958) to place the species in the subgenus Varanus
along with other large Australian goannas, but more
recent studies suggest that this is a dwarf monitor of the Odatria
subgenus (e .g. Baverstock et al
lively little goanna reaches a maximum size of about 70cm TL. The tail is 173-210% of SVL
(Storr1980). At hatching they measure less than 8cm SVL and sexual maturity is attained in
both sexes at about 22cm SVL (Shine 1986).
Mitchell's goanna is found in both freshwater and marine habitats. They are said to inhabit
mangrove swamps and coasts as well as along inland rivers, streams, lakes and billabongs.
Around Jabiru. Northern Territory, they occupy areas that are only intennittently flooded and
are usually seen on trees close to the water. During the wet season they expand their habitat
to take advantage of temporarily flooded areas (Shine 1986). Diet in this area is comprised
largely of fish and crabs. together with frogs, lizards, reptile eggs, small mammals, nestling
birds and terrestrial invertebrates (orthopterans, arachnids. beetles etc. ). A specimen
examined by Losos & Greene (1986) also contained a frog and Schmida (1985) considered
frogs to be their most important prey item (he considers this diet to be responsible for the
large numbers of parasites which the goannas harbour) . At Jaribu breeding occurs during the
dry season. with gravid females found from April - June containing up to 12 small (2.5 ×
1.3cm, volume 4.4cc) eggs. The diet of Mitchell's goanna indicates that they forage both on
the ground and in the water. However, during most of the day (and throughout the night)
they rest on tree branches overhanging the water (Peters 1971b. Shine 1986).
There appear to be no published reports of captive breeding for Mitchell's goanna. In
captivity they are said to be very nervous and shy (Peters 1971 b; Murphy 1972) and need to
be housed in a large. high enclosure with high temperatures and plenty of hiding places. both
on and above the ground. In general they tolerate each other well but may harass smaller or
weaker lizards. Their diet should contain animals of both aquatic and terrestrial origin.