The intelligence of the Monitor lizard

Monitor lizards are very intelligent and some species appear to be able to count and read: studies carried out by feeding V. albigularis in a San Diego zoo have indicated that they are able to recognize numbers up to six

by Lorenzo Ciotti
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The intelligence of the Monitor lizard

Monitor lizards resemble large lizards; they possess a relatively high metabolic rate for reptiles and are endowed with several sensory adaptations, which benefit them in hunting their prey. Recent studies indicate that varanids have a highly infectious bite due to the bacterial flora present in the saliva and some highly toxic poison glands.

Some varanids are apparently capable of asexually reproducing. The various species of monitor lizard cover a large area, including Africa, southern India, Sri Lanka to China, south of Southeast Asia, Indonesia, the Philippines, New Guinea, l 'Australia and the islands of the Indian Ocean and the South China Sea.

It is thought that varanids descend from a probable ancestor with burrowing habits, belonging to the Platynota group. Among the various forms dating back to the upper Cretaceous, we can include the robust Palaeosaniwa and the poisonous Estesia.

The first fossil remains attributable to varanids, such as Telmasaurus and Saniwides, date back to the end of the Cretaceous, although complete specimens, such as those of Saniwa, are known only in Eocene soils, dating back to about 50 million years ago.

The genus Varanus first emerged in Laurasia. The first well-known representative of the genus Varanus dates back to the lower Miocene, about 18 million years ago, of Kenya: this species, known as Varanus rusingensis, must already have been very similar to the current Nile monitor.

During the late Oligocene and early Miocene the group had already dispersed to Australia, New Guinea and the Solomon Islands on three separate occasions. At the end of the Miocene, the genus was also present in Africa, Arabia, Asia and Eastern Europe.

During the Pleistocene, gigantic lizards lived in Southeast Asia and Australasia, of which the largest and best known member is the megalania. This species is an iconic member of the Australian Pleistocene megafauna, believed to have survived until around 50,000 years ago.

The intelligence of the Monitor lizard

Monitor lizards are very intelligent and some species appear to be able to count and read: studies carried out by feeding V. albigularis in a San Diego zoo have indicated that they are able to recognize numbers up to six.

Two V. niloticus have been observed feeding: one of them distracts the female crocodile, while the other raids the nest to take possession of the eggs. His partner returns, after having distracted the crocodile sufficiently, and together they feed on the eggs.

Komodo dragons in Smithsonian National Zoological Park, Washington DC, recognize their keepers and possess distinct personalities.