Irwin's turtle

Common name: Irwin's turtle

Scientific name: Elseya irwini

Family: Chelidae (side-necked turtles)

Conservation status: This species is listed as Least concern in Queensland under the Nature Conservation Act 1992.

Description

This is a large, short-necked turtle with a carapace (upper shell) up to 330mm in length (width 260mm). There are two separate, genetically distinct populations: one is confined to the Johnstone River in the Wet Tropics region and the other is confined to the Burdekin River catchment. Adult female Burdekin E. irwini are distinguished from other Elseya in having pale yellow colouration on the head that extends to the top of the crown. By contrast, Irwin’s turtles from the Johnstone River have white or cream colouring on their throat and sides of the head, as also seen in other Elseya species. Both Burdekin and Johnstone River adults can also have distinctive pink noses. In the two river catchments where this turtle occurs, adult E. irwini turtles generally attain a larger size than any other short-necked turtles present.

Habitat and distribution

Irwin's turtle is found in the Burdekin catchment (which includes the Bowen River) in North Queensland and the Johnstone River in Far North Queensland. It was first discovered in the Burdekin catchment by Steve Irwin and his father Bob in 1990. In the Johnstone catchment it had been known to be present by scientists since the 1970s, when it was known as the northern snapping turtle (Elseya dentata).

Behaviour and life history

These turtles will often bask on exposed rocks and logs to raise their body temperature and commonly float with only their heads breaking the surface of the water. At night they have been known to emerge into shallow riffle zones to feed on algae that cover boulders. Irwin’s turtles lay their eggs in nests dug into river banks, with nesting occurring anywhere between April and July. In common with other ‘snapping’ turtles, adult Irwin’s turtles are mainly herbivorous. Both male and female turtles show a strong preference for leaf matter and stems sourced from terrestrial riparian vegetation. Fruit, algae, aquatic plants and non-native pasture grasses are also consumed but usually in a smaller proportion compared to leaf material. Animal matter such as shrimp, molluscs, aquatic insects and carrion are also consumed but may not be as important for adults in the wild. Juveniles tend to be less herbivorous and more carnivorous than adults. In captivity Irwin’s turtle will eat fish and raw meat, as well as vegetable material.

Threatening processes

A number of potential threats have been identified, although little information is available on the degree and extent of these threats. To date, habitat loss and degradation, nest predation and disturbance by feral predators (predominantly pigs) and pollution are considered important threats.

Recovery actions

While more information is still needed on distribution, abundance and the threats facing Irwin’s turtle, some work has begun. The Threatened Species Unit of the department has been collecting data on this turtle in the upper reaches of the Johnstone River to guide conservation management of this turtle into the future.

What can be done to help this species?

The most important thing that can be done to help this species is to preserve intact native riparian (riverside) vegetation. This one act will help maintain water quality, nesting bank habitat and food for this species. In addition, the fencing of nesting banks and implementation of feral animal control may be appropriate in some situations.

Any sightings of 'white-headed turtles' in the Burdekin and Johnstone catchment should be reported to the Threatened Species unit of the department. Contact the Threatened Species Unit at Threatened.Species@detsi.qld.gov.au or the WildNet team at WildNet@science.detsi.qld.gov.au

Related information

Cann, J. (1998). Australian Freshwater Turtles, Beaumont Publishing.

Cann, J. (2008). A Wild Australia Guide. Freshwater Turtles. Steve Parish Publishing.