The New Guinea crocodile (Crocodylus novaeguineae) is a freshwater crocodile found only in Papua New Guinea and in the Papua Province of Indonesia. Papua New Guinea is the eastern side of the island of New Guinea, which is the second-largest island in the world. The Papua Province of Indonesia makes up the western part of the same island. It is located in the Oceania region in the Pacific Ocean near Australia. The island has great biodiversity, and the animal life is more closely related to that of Australia and New Zealand than that of the rest of Indonesia and Asia.

As a freshwater crocodile, the New Guinea crocodile is found in inland freshwater lakes, swamps, marshes, and rivers. The larger saltwater crocodiles also live on the island, but they occupy different habitats, including deep pools, fast-moving streams, and brackish areas closer to the coast. Though their habitats sometimes overlap, the saltwater crocodiles and the New Guinea crocodiles do not generally compete for food.

There are two different populations of New Guinea crocodiles, separated by the central highlands of New Guinea. These two populations have slightly different physical characteristics, though they are currently considered to be the same species.

The New Guinea crocodile is hunted both for its meat and its hide. For many villages in Papua New Guinea, hunting these animals is the main source of income. There are currently restrictions in place to make sure overhunting does not occur and that the crocodile populations remain at healthy levels.

  1. The New Guinea crocodile and saltwater crocodiles live near each other on the same island. How might these crocodiles coexist successfully on the same island?

    • Answer

      The two types of crocodile live mostly in different habitats on the island. They also do not compete for food, as the larger saltwater crocodiles are thought to hunt larger prey, while the smaller New Guinea crocodiles primarily eat birds and fish.

  2. Find the island of New Guinea on a map. Though the overall animal population on the island more closely resembles that of Australia and New Zealand, there are also animals with origins in Asia. Why might this mixture of animals occur?

    • Answer

      New Guinea is close to Australia and was at one time connected to it by a land bridge. New Guinea and Australia are both on the Australian plate and were both once part of the Gondwana supercontinent. A chain of islands also connects New Guinea to mainland Asia, making it easier for animals to cross into New Guinea from there. 

  3. Until 1928, scientists considered the New Guinea crocodile to be part of the saltwater crocodile species. Currently, the populations of New Guinea crocodiles on either side of the central highlands are still considered the same species, though they have some different characteristics. What factors do scientists consider when deciding to classify an animal as a different species?

    • Answer

      There are criteria to identify species, including their anatomy, the history of how they evolved, and even their behavior. Among close relative, scientists also look to see if they interbreed. Although there are criteria, there is often a lot of disagreement among scientists when deciding whether to categorize animals that are closely related as a new species. 

Noun

all the different kinds of living organisms within a given area.

brackish water
Noun

salty water, usually a mixture of seawater and freshwater.

freshwater
Adjective

having to do with a habitat or ecosystem of a lake, river, or spring.

Gondwana Game Reserve
Noun

large zoological park in South Africa.

Oceania
Noun

region including island groups in the South Pacific.

overhunt
Verb

to capture and kill enough animals to reduce their breeding population below sustainable levels.

supercontinent
Noun

ancient, giant landmass that split apart to form all the continents we know today.