Murray Short-Necked Turtle

Scientific name:

Emydura macquarii

Other common names

Murray Turtle, Murray River Turtle, Macquarie Turtle, Brisbane River Turtle, Clarence River Turtle, Macleay River Turtle, Hunter River Turtle, Sydney Basin Turtle, Bellinger River Turtle, Storm King Dam Turtle

Description

The Murray Short-necked Turtle has a broad, oblong, shell (carapace) that is wider towards the back end, and may have either a smooth or a slightly serrated posterior rim. The shell is olive to brown in colour. The edges at the rear of the shell may be flared, especially in adult males. The edges along the sides can be upturned.

The Marray Short-necked Turtle has two whisker-like tactile organs (barbells) on their chin. The turtle’s head is covered with smooth skin. Their head, neck and limbs are grey to olive brown in colour. The colour on the underside of these turtles ranges from bone to a very pale yellow.

The turtle’s head is relatively small compared to the size of their body. They have a cream-coloured or yellowish stripe which runs from the corner of their mouth to their neck and a yellow spot on each side of their chin. The turtle’s eyes are small with a yellow iris and a round black pupil.

The shell of the male is up to 34cm long, while the female’s shell can measure up to 30cm. An adult female Marray Short-necked Turtle can weigh up to 4kg. The male Murray Short-necked Turtle has a much fatter and longer tail than the female.

Habitat

The Murray Short-necked Turtle is a common turtle in the rivers and large wetlands of the Murray-Darling system. It is mostly commonly found in the southern areas of the river system but it can also live in the northern regions, as high as 1000 metres above sea level. This is the highest altitude known for an Australian turtle.

Murray Short-necked Turtles prefer to live in slow moving or stagnant waters.

Behaviour

The Murray Short-Necked Turtle will eat virtually any food they can find. This makes these turtles opportunistic omnivores. They prefer to eat algae and carrion (dead animals) but they also eat molluscs, crustaceans and vegetable matter such as fruits and water plants. The animals they eat include: fresh water sponges, caddisfly larvae, midge larvae and pupae, dragonfly nymphs, crayfish, shrimps and freshwater snails. The younger turtles tend to be carnivorous, relying on aquatic insect larvae and insects that fall into the water. Adult turtles tend to eat a larger proportion of vegetable matter such as fruits and water plants. Older turtles tend to become largely herbivorous with up to 95% of their diet being vegetation.

In the southern part of their range these turtles have been seen in large numbers, with their limbs and neck extended, basking in the sun.

These turtles mate from March to April. The females prefer to dig nests into stream banks during or after heavy rainfall, from late October until the end of December. They usually produce one clutch of eggs each year but in year with favourable conditions they have been known to lay as many as three clutches in a season. They can lay anywhere from 6 to 25 eggs in a clutch but around 15 eggs is usual.

During the nesting season, their nesting activity peaks around dawn and dusk each day. The nests are likely to be preyed upon by birds, primarily Australian Bell Magpies, and foxes. A study of these turtle’s nests along the Murray found that 96% of nests had been disturbed, mainly by foxes and birds but also by water-rats and goannas.

The turtle’s eggs are about 33mm long and 23mm wide and have brittle shells. When they are laid the shells are translucent. Within a day a small opaque patch forms on top of the shell. At least one end of the egg also becomes opaque before hatching. The opaque part of the shell develops as the shell partially dries. Water is lost through this part of the shell allowing the exchange of respiratory gases. This allows the shell to supply an increasing amount of air to the developing turtle during incubation. The incubation takes between 66 and 85 days, with the average being about 75 days. When the turtle hatch their shell is about 3cm long.

References/Sources

Encyclopedia of Australian Wildlife, Readers Digest

The Australian Museum Encyclopedia of Australian Animals: Reptiles. Angus & Robertson, 1992, ISBN 0 207 17379 6