Species of the day one hundred and thirty seven: Western Swamp Tortoise (Pseudemydura umbrina)
Small note: This species is very dear to me as not only is it endemic to my state, but it is located quite close to my hometown and I have been honored enough to recently see first hand some of the conservation efforts to save this species.
Scientific Classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Family: Chelidae
Genus: Pseudemydura
Species: Pseudemydura umbrina
Size: Male weight: up to 0.55 kg
Female weight: up to 0.41 kg
Male carapace length: up to 155 mm
Female carapace length: up to 135 mm
Description: This small freshwater turtle is the most endangered Australian reptile and the most endangered tortoise species in the world. The flattened carapace appears square from above and varies in colour from yellow-brown to black depending on the area. The flattened head is covered by a single large bony plate, or scute. Unusually amongst turtles, the female is smaller than the male. The plastron, or undershell, of the Western Swamp Tortoise is paler than the carapace and extremely broad; it often has a pattern of black spots on a yellow background. The short legs are covered with bony plates and the feet are clawed.
Habitat and Distribution: The Western Swamp Tortoise inhabits shallow, temporary swamps that are only available after the autumn rains, and which occur on clay or sand-over-clay soils. Endemic to Western Australia, this turtle has probably never been very abundant. First discovered in 1839, the species was believed to be extinct until a Perth schoolboy ‘rediscovered’ the turtle in 1953. At this time the species was restricted to a narrow region of the Swan Coastal Plain near Perth in Western Australia, and today it is found only in two protected sites at the edge of the city: Ellen Brook Nature Reserve, and an introduced population at Twin Swamps.
Biology and Ecology: The Western Swamp Tortoise is only active for half the year, spending the dry summer months in a dormant state known as aestivation. Within the Ellen Brook Nature Reserve individuals tend to aestivate in holes in the clay soil whilst turtles at Twin Swamps Nature Reserve are more commonly found seeking protection under leaf litter or fallen braches. The swamps begin to fill up with water in June and July, when turtles can be found foraging for live food including insect larvae, earthworms and tadpoles. As temperatures rise the turtles increase their food intake, putting on excess fat for the months of dormancy to come. By November, the swamps are drying out and the turtles leave the water to aestivate through the summer and autumn.
Western Swamp Tortoise are unusual in that they only produce one clutch of eggs per year and they are the only turtles to dig a nest with their front, rather than back, flippers. In November and early December, three to five hard-shelled eggs are laid into the nest, and are then covered. Eggs will stay in the nest for the summer months; hatchlings emerging the following winter. It is thought that Western Swamp Tortoises may live for as long as 60 or 70 years.
Status and Threats: The Western Swamp Tortoise is classified as Critically Endangered under the IUCN Redlist. This turtle has always had a restricted distribution; the species depends on marginal habitat and has low reproductive potential. Today however, the western swamp turtle is Critically Endangered and the population at Twin Swamps became extinct in 1985. The swamps of this turtles’ habitat have been drained and filled in for agricultural purposes, greatly reducing the available range. In addition, the population at Twin Swamps in particular, suffered from predation by the introduced red fox (Vulpes vulpes); aestivating individuals protected only by leaf litter are especially vulnerable.
Websites for Western Swamp Turtle conservation:
