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![]() Featured on our programme, The Research File. Click to hear the full report. |
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Caring, Sharing Male
But it takes two to tango and it seems the male of the species is
even more crucial than the female when it comes to the timing of
reproductive events. The males here also undergo ultrasound examination
and hormone injections. "In salamanders, if the male isn't ready then
forget it," says Schaftenaar. "Between July and September he gets a
swelling around his cloaca - that's the opening where faeces, urine and
semen or eggs leave the body. Only the male gets this. We think he
gives off pheromones, kind of hormones, that a female can smell and it
stimulates her to ovulate." And getting the female in the mood at the
right time is critical for the male salamander. "They produce semen
only once per year. This makes them very vulnerable, because in the
wild they have to find a female at the right time or wait until the
following year to breed!"
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High Hopes
It's a process that needs a helping hand in captive salamanders.
They've never bred with hormonal assistance in zoos anywhere outside
China and it's not known whether anyone there has had any success. In
Japan researchers have been breeding the related Japanese species of
giant salamander and Willem Schaftenaar has been exchanging information
with them. He only discovered that the Chinese salamanders at Blijdorp
were physically capable of breeding by conducting extensive studies of
ultrasound scans and blood samples from both males and females.
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The age of the creatures is still a mystery as they were all confiscated from a number of smuggled imports about ten years ago. Last year the vet collected sperm by rubbing the males' abdomens and managed to fertilise about 100 eggs, but the embryos died after only two weeks. This year, he's more optimistic.
"Incubation takes exactly 50 days. We'll hang the eggs over bamboo sticks so they get more water and oxygen flowing over them than last year. We don't know how big they'd be when they hatch, but the Japanese species are 8cm long. Once they've hatched they'll have to be fed and that's another thing we don't know - what they eat. We'll have to divide them into groups and try them on different things and hope to find something they like quickly!"