Page 112 - Present Day Wildlife_Float

Monitor lizards are the only true lizards in the extant genus Varanus in the family Va-
ranidae *. There are about 80 species of true lizards in 11 subgenera in the genus. They are found in
Africa, Asia, and countries and islands of Oceania with one species found in the Americas as an inva-
sive species. The largest of the species, and the largest lizard in the world, is the Komodo dragon
which is around 3 metres in length and weighs around 130 to 150 kg. The smallest is the, Dampier
Peninsula monitor, which is a tiny, 23 cm in

length, and fully grown weighs only 16.3 grams.
The earliest ancestor of the present day monitor
lizard is believed to have appeared around 56 to
33.9 million years ago.

True monitors have long lean bodies, and
most, not all - see perentie Varanus giganteus -
have four short but robust legs with large flat
paws brandishing five long clawed toes. They
walk with a ponderous table-like gait; however,
they can move, incredibly fast, in short bursts.
They have a long slen-
der, elongated neck, a
large head with large
round eyes high on
the side of their scull.
They have a rounded
*Family Varanidae snout and powerful

Genus Varanus jaws lined with curved serrated teeth.
Taxonomy They have a long thin forked tipped
Subgenus Empagusia: tongue that acts as a sensor, collecting
information from the air around it
Subgenus Euprepiosaurus: and feeding a special sensor on the
Subgenus Hapturosaurus: roof of its mouth called a Jacobson's
Subgenus Odatria: organ. With this information it can detect food and prey a kilo-
Subgenus Papusaurus metre away. Most have long thick tapering tails that can make
up 50% of their body length. They use this heavy tail as a weap-
Subgenus Philippinosaurus: on and for support when they stand erect to fight other moni-
Subgenus Polydaedalus: tors. Most true monitor start life with colourful striped bodies
Subgenus Psammosaurus: that changes in adult hood into faded speckles or stripes with
Subgenus Solomonsaurus their tails often retaining some of the bright stripes or the tip of
Subgenus Soterosaurus their tail being white or lightly coloured.

Subgenus Varanus Monitor lizards are a wide and diverse species. Most are
terrestrial, while some are arboreal and others semiaquatic.
Across the areas of the globe they inhabit they are found in almost every environmental condition,
with the smaller of the species tending to inhabit ponds, marshlands woodlands, and built up subur-
ban areas, while the larger ones tend to be found in large open marshlands, dry rocky and dusty bush-
land areas. Finding different species sharing the same environment is not unusual. They are territorial
and unsociable animals, and tend to live on their own, coming together only to mate. They can also be
extremely aggressive, protecting their territory with vicious attacks on interlopers. Males, at mating
time, are willing to maim and kill to become the dominant partner.

Apart from a few species like, Varanus bitatawa, V. mabitang and V. olivaceus, which are
frugivores, monitor lizards are primarily carnivores. Due to the difference in size and location their
eating preferences do vary. In general the smaller ones tend to have a diet of insects, crustaceans,
molluscs, fish, small reptiles, birds and their eggs, and small mammals. The larger ones eat much of
what their smaller counterparts consume but also eat much larger animals. The Komodo dragon, for
instance, is known to prey on and kill a fully grown deer, while most will prey on wild boar and ani-
mals of comparable size, even juvenile monitor lizards are fair game. Recent studies have discovered
that some species of monitors have a venomous gland on the inside of their lower jaw. This venom
seems to come in two forms; an anti-blood coagulant and one that paralyses its victim. However,
some studies have discovered that not all animals are affected by these venoms, suggesting some ani-
mals could be immune. (See: Lizard)