A crocodile skink is a small reptile that is native to Papua New Guinea and its surrounding islands, including the Solomon Islands and Admiralty Islands. Its name derives from the appearance of its body, which resembles a miniature crocodile. Part of the scincidae family, there are eight recognized species of crocodile skinks, including Tribolonotus annectens, T. blanchardi, T. brongersmai, T. gracilis and T. novaeguineae. The others are T. ponceleti, T. pseudoponceleti and T. schmidti.
Two of the more popular species that are kept as exotic pets, T. gracilis — commonly referred to as the orange-eyed or red-eyed crocodile skink — and T. novaeguineae, are native to mainland New Guinea. Their color ranges from dark brown to reddish brown, depending on their age. Along their back are spiny protrusions or scales, which contribute to the “crocodile” part of their name. The red- or orange-eyed crocodile skink also features a colorful orange marking that outlines the eyes.
Crocodile skinks of mainland New Guinea prefer the lush areas of the tropical rainforest. Their diet consists mainly of insects such as crickets and beetles. At adulthood, they can reach about 10 inches (25 cm) in length, depending on the species. The average length for an adult red-eyed crocodile skink is 8 inches (20 cm), with males generally larger than females. Crocodile skinks are hatched from eggs and are approximately 2 inches (5 cm) at birth.
These distinct lizards differ from most skinks. Many skink varieties do not display a pronounced neck, but the crocodile skink has a short neck area that extends into a triangular-shaped head, resembling that of a dinosaur. Another distinct characteristic of crocodile skinks from New Guinea is their ability to vocalize, which usually occurs when they feel threatened. Crocodile skinks also have characteristics that are similar to those of other skinks, such as the ability to detach part of the tail, which will regenerate over time.
With the exception of the T. gracilis and T. novaeguineae, these types of skinks are relatively unknown outside of their native homeland. The T. ponceleti, T. blanchardi, T. schmidti and T. pseudoponceleti are native to the Solomon Islands. The T. annectens, also known as the Zweifel’s helmet skink, roams parts of New Britain and Bismarck Archipelago. The T. brongersmai, or Brongersma’s helmet skink, also is found in Bismarck Archipelago as well as the Admiralty Islands.
The environment in which each of these crocodile skink breeds resides varies from tropical lowlands to mountainous regions, but they all prefer a moist habitat located near a source of fresh water. Crocodile skinks are fairly docile, which has made them a popular skink species to keep as pets. With few natural predators in the wild, the average lifespan of these reptiles is about 10 years.