The largest of the long-necked turtles, the broad-shelled turtle’s combined shell and extended neck lengths may exceed 80cm. They have an extraordinary ability to extract oxygen from fresh water by pumping it through veined cavities in the throat and vent enabling them to remain submerged for extended periods of time. The shell is usually dark grey-brown in colour, as is the upper part of the head and neck, while the throat is pale grey or creamy in colour.
Broad-shelled long-necks are rarely seen out of the water. They utilise large, slow-moving or still bodies of water in southeastern Australia, from southern Queensland to eastern South Australia. During winter they hibernate by burrowing into the mud on the river bottom.
These turtles lie in ambush, partially hidden in the mud on the river bottom. The head is all that is visible, awaiting a passing fish or frog. These are snatched with tremendous speed by thrusting out the neck with the mouth open wide. Prey items as big as ducklings may taken by particularly large turtles.
The female broad-shelled turtle usually lays her eggs in autumn, between March and May. About 12 hard-shelled eggs are laid in a riverbank nest and are left to incubate all through winter, hatching many months later in spring.