Echidnas in Queensland have been observed breeding in a style not commonly seen in the Sunshine State, exciting researchers of the enigmatic egg-laying mammals.
Large groups of echidnas have been photographed engaging in a mating behaviour known as “training”, where one female is pursued by a number of males, in south-west Queensland.
Training has been documented in South Australia, most notably among animals on Kangaroo Island.
Stephen Johnston, an associate professor at the University of Queensland’s faculty of science, told Guardian Australia echidnas were found across Australia but the behaviour was not universal.
He said there was speculation among researchers that it reflected competition among the males for the female’s attention, with the dominant male first in line and “those that are probably not as sexually capable” further back.
“It’s just part of the natural selection process.”
Another theory was that it occurred only in areas with large numbers of echidnas, where the population density was high enough, said Johnston, who is a member of the Australian Society of Reproduction and the Australian Mammal Society.
Unusually, echidnas breed for a relatively short period of time during winter; most Australian mammals tend to reproduce in spring.
“This time of year, the boys are out looking for the girls. The females are in oestrus, the girls are being almost harassed by the boys, to the point where one will ultimately win out.”
But it was difficult to explain the behaviour when so little was known about their reproductive biology in general, said Johnston – even about “basic things” such as their oestrus cycle.
Echidnas’ biology is different to other mammals because, as monotremes, they lay eggs. The male has a four-headed penis and uses two of those heads at a time to ejaculate sperm.
They also live in dens, making them difficult to track.
Many observations made of animals in the wild had yet to be validated by researchers, said Johnston, even though they were widespread and relatively common.
“This is something we’re trying to address,” he said. “They are a really cryptic little animal. They’re ubiquitous ... you will find them everywhere, all over Australia, from the bush to the snow to the desert and on the coast.”
He was hopeful that the University of Queensland’s study of the colony of 22 echidnas at the Currumbin wildlife sanctuary would help unlock their “secret”.
“They’re just a really tricky animal, because of their habits, to get some of this fine detail about their reproduction.”
Fourteen short-beaked echidna puggles have been born into the Currumbin breeding program in the past five years.
Johnston told Guardian Australia last year that the program had been successful: “Now we can pretty much predict that, if we put A and B together and provide the right environmental conditions, a mating is likely to be successful.”
