Tortoise 1375 does his duty for the future of his species
A virile and extremely rare tortoise is on a pleasurable visit to Perth Zoo after he stunned scientists by turning up in a swamp in the city.
The male western swamp tortoise was not one of the remaining specimens accounted for in the wild — there are fewer than 300 of those, and zoologists have either microchipped or marked the shells of each one.
Researcher Gerald Kuchling spotted this young buck last December at a fenced swamp where several western swamp tortoises live protected from foxes, dogs and cats. It had entered via a tortoise-size gate that allows Australia’s rarest reptiles to come and go as they please.
Now known as 1375, it is temporarily in the zoo’s breeding ponds to mate with four females as part of the program credited with bringing the western swamp tortoise back from the brink.
It is being fed daily on minced puddings of rats, fish and yabbies, with the shells included for calcium.
Though 1375 arrived at Perth Zoo only two weeks ago, it has already been paired with one female and is on a second date.
There is an air of excitement at the zoo about 1375’s first pairing and the prospect of new genes in the breeding program.
“It was successful, we witnessed that. There is no privacy around here,” zookeeper Lesley Shaw said.
Western swamp tortoises were thought extinct in 1953 when Perth schoolboy Robert Boyd presented two of them at the annual Wildlife Show at Perth Town Hall. The late naturalist Harry Butler was there that day to hear Robert explain that his cousin had found them crossing a road in Bullsbrook, 40km northeast of the centre of Perth.
Even when its wild populations were much larger, the species with the distinctive permanent grin was restricted to the clay-lined swamps of the Swan coastal plain in Perth and its immediate surrounds. But the clay was perfect for making housebricks so the swamps were mined heavily as Perth grew, and by the mid-1980s there were fewer than 30 western swamp tortoises in the wild.
Winter is a busy time for Perth Zoo program leader Peter Mawson and others who look after the captive population of western swamp tortoises; hatchlings are growing fast on a diet of mosquito larvae and water fleas, while the adults have woken from their summer-long sleep to breed.
Since 1989, Perth Zoo has bred more than 800 western swamp tortoises and now they are in captivity at Adelaide Zoo as well. Dr Mawson said some things were still unknown: nobody is certain if the lifespan of the western swamp tortoise is closer to 80 or 175 years, or for how long the adults remain fertile. Some of the tortoises are known to have bred every year since 1983.
Dr Mawson and his team are devoted to continuing their slow and steady progress. “Whatever you do, it’s going to take a long time to make a difference,” he said.