Crocodile Monitor

The Crocodile Monitor is one of the largest species of lizard in the world. They can grow to a maximum length of around 8 feet.

These lizards are native to New Guinea and some of the surrounding islands. They are also referred to as the Papuan Monitor, the Salvadori’s Monitor and Artellia.

Crocodile Monitor
Greg Hume, CC BY-SA 3.0 via Wikimedia Commons

Crocodile Monitor Taxonomy

The Crocodile Monitor belongs to the Varanidae family of lizards. This family contains only one genus of living lizards. There are two extinct genera associated with this family, Ovoo and Saniwa.

The remaining genus, and the genus that the Crocodile Monitor belongs to is called Varanus. This is essentially the genus of Monitor Lizards, which are native to Africa, Asia and Oceania.

The closest living relatives to the lizards in the Varanus genus are the species in the anguid and helodermatid genera.

The lizards in the anguid genus are native to the Northern Hemisphere and include the glass lizards and the alligator lizards. 

There are only 5 species of lizards in the helodermatid genus and they are all venomous. This family includes the Gila Monster.

Monitors are a large genus of lizard that contains over 80 different species at the time of writing. However, many species and sub-species are constantly being disputed so the exact number will change from time to time.

The group of Monitor lizards include some of the largest species of lizards in the world such as the Komodo Dragon and Nile Monitor.

The genus name, Varanus is derived from the Arabic word ‘waral’ which simply translates into Monitor.

The scientific name for the Crocodile Monitor is Varanus salvadorii. It was first described in 1878 by naturalists Wilhelm Peters and Giacomo Doria.

The name salvadorii is a Latinization of Salvadori as this lizard was named after an Italian ornithologist who worked in New Guinea named Tommaso Salvadori.

Crocodile Monitor Description

The Crocodile Monitor is one of the largest species of lizard in the world. Specimens have been recorded measuring over 8 feet in length.

They are dark green, grey or blackish in color with yellowish spots all over their body. These spots can vary in size and shape.

The patterning extends to their tail and also appears yellow or white in color. The pattern on the tail usually consists of bands that form full rings around the tail.

They have a strong muscular head and neck while their tail is extremely long and makes up around two thirds of the lizard’s overall length.

It can be hard to differentiate between a male and female Crocodile Monitor but there are subtle differences. 

Males typically have larger and broader heads than females. They also have subtle hemipenal bulges but they can be difficult to identify. Because of this, visual identification can be difficult.

Natural Habitat and Distribution

The Crocodile Monitor is native to the island of New Guinea. This large island is divided into three separate regions, West Papua, Papua and Papua New Guinea.

West Papua and Papua are both provinces of Indonesia. West Papua is made up of the two Western Peninsulas of the island while Papua is made up of the rest of the Western half of the island.

Papua New Guinea is an independent country and is made up of the Eastern half of the island. The Crocodile Monitor can be found in all three of these regions.

While their populations are very fragmented, they can be found in all 3 of these regions at elevations up to elevations of around 2,500 feet.

They typically live in the tropical and sub-tropical areas within their range. However, they will also live in mangrove swamps, riparian woodlands and floodplain forests.

All of these types of habitats contain large sources of water and these lizards are excellent swimmers.

They live in a part of the world that has a huge diversity of different reptile species. They share part of their geographic distribution with a wide range of other reptiles such as the Bismarck Ringed Python, Blue Tailed Monitor, Blue Tongue Skink, Boelen’s Python, Amethystine Python, Emerald Tree Monitor, Mangrove Monitor, Mourning Gecko, Peach Throat Monitor, Black Tree Monitor and the Pink Bellied Side Neck Turtle. However, some of these reptiles may have different habitat niches.

Crocodile Monitor Behaviour

 The Crocodile Monitor is an arboreal species and will spend most of its time in the trees. However, they will also come down to ground level to search for food along the waterways.

They have long and powerful tails that they will use as a weapon to defend themselves when they feel threatened.

Not a lot of research has been done about these lizards’ diet in the wild but it is believed that they will consume a wide variety of prey including small mammals, rodents, fish, birds, eggs and carrion.