Emydura subglobosa hatchling

Emydura subglobosa, hatchling. Photograph by Ellen Nicol

 

Most of the water turtles (called "tortoises" in Australia) of the Australasian area fall into one of two categories: the snake-necked species and the short-necked species. Having specialized in these turtles for over 20 years, I still find them some of the most desirable turtles to keep if you fancy aquatic species. Species native to Australia exclusively are not available for legal import because Australia does not permit export of or trafficking in any of its native fauna. Species whose range extends outside of Australia, such as Emydura subglobosa and Chelodina novaeguineae, are occasionally imported. Our groups of these species breed regularly.

Emydura subglobosa (or in some reference works E. albertisii) is one of the Australasian short-necked species. Confusion exists over the taxonomy of reptiles of the region, and I understand that many of the reptiles are being reclassified after many years of study by biologists, but complete information has not yet become available.

The carapace of this appealing side-necked turtle is a medium to charcoal gray color with no design. The plastron bridge and underside of the marginal scutes have a striking lighter gray and coral pink design which does not fade as the animal matures. The head is dark gray with a yellow stripe behind the eye, and there is a bright coral design under the bottom jaw. The male is smaller than the female, and he has a more elongated tail. Adult size usually does not exceed 8-9 inches, and they breed readily in captivity. (Note the final paragraph herein!)

Emydura subglobosa will eat almost anything: worms, lean beef, chicken livers/hearts, fish, Trout Chow, as well as the occasional piece of banana (banana will foul the water rather quickly), various greens such as Romaine lettuce, escarole, and slivers of zucchini squash. A calcium block, which you can make from plaster of Paris mixed with water and dried, should be in their water at all times.

These turtles are highly aquatic and rarely leave the pond except to bask or nest. They are inveterate baskers, and will perch by the hour in the sunshine or under a heat lamp. Outdoors, they are the first ones sunning in the morning, and the last ones to return to the water at dusk. Indoors, they will bask in the beam of a 75-watt spotlight, but natural sunlight (not passed through glass) is better for them. If you cannot provide natural sunlight, an overhead Vita-lite lamp (which provides wide-spectrum light) should be used as well as the incandescent bulb. Cork bark, plastic greenery or ramps of some kind should be provided to enable the turtles to climb out of the water or to be supported when they sleep at night.

In Florida we are able to keep most of our turtles outdoors year around. Emydura subglobosa adults are housed in covered screen-sided pens that are 8' square and 2' high, with a sunken 300-gallon heavy plastic cattle tank sunk to ground level. There are wooden and screen ramps, as well as sunken logs attached to the sides of the tank so they can easily exit the pond. We do not use filters, but the pond water is completely drained frequently or when it is dirty. It is then that we inspect tank occupants for illness or injury.

Reproduction

Over 10 years ago, we acquired 3 juvenile female red-bellied short-necked turtles as mates for our lone juvenile male. The females had lesions over much of their shells, but now the sores are healed and the turtles have turned into perfect adults, reproducing every year since 1987. All of the females produce multiple clutches of eggs, and the nesting season lasts from February to July.

My earlier records were somewhat sketchy, but since 1990, I have kept detailed records on the reproduction of this species. In 1990, 78 eggs were deposited and 58 of these hatched. In 1991, 65 eggs of 76 hatched, and in 1992 we had 81 eggs, 70 of which produced live babies. So for the 3 years, 235 eggs were deposited and 193 hatched. Each year we also found babies that had hatched in the ground, and these figures do not reflect those numbers.

Their nesting behavior is quite different from our other Australasian turtles that will come on land and pace in the grass for up to 2 weeks before finding a spot that suits them. By contrast, the red-bellied short-necked turtles come out on land once or twice--mostly during the night or early morning--and quickly dig shallow nests, often between grass tussocks, which makes eggs harder to locate. The female covers the nest very carelessly, not compacting the soil with her plastron. Often a nest can be spotted by the amount of loose dirt not replaced in digging the nest hole. While snake-necked turtle females can take up to 4 hours to deposit eggs and cover the nest to their satisfaction, E. subglobosa take only about 1 hour from start to finish. Their work shows it when compared to the snake-necked turtles, whose nests are almost impossible to find because they are so well camouflaged.