Two-toed sloths lead ‘lazy’ sex lives
Scientists have revealed the hidden sexual habits of Hoffmann’s two-toed sloths.
London: Scientists have revealed the hidden sexual habits of Hoffmann’s two-toed sloths.
The researchers analysed the mating activity of the “lazy” mammals in Costa Rica to assess the effect of a sedentary lifestyle.
Ecologists found a mating system where male sloths did not monopolise females but did show signs of defending some territory.
The study may help scientists understand how to protect other species threatened with habitat fragmentation.
“It’s not a total free for all,” the BBC quoted one of the team, Dr Zach Peery, as saying.
Although sloth physiology and anatomy is well understood, their behaviour is not, said Dr Jonathan Pauli, who co-authored the University of Wisconsin study with Dr Zach Peery.
Relatives of the two-toed Hoffmann’s sloth once lived on the ground, rivalling the mammoths for size and even had fearsome 50cm long claws. Experts have learned more about the distant but formidable members of the sloth family, from fossils.
“One of the real highlights...for a cryptic mammal like this is the ability for us... to almost get a census of these populations,” he said.
The research was part of an ongoing monitoring programme in which males and female two-toed sloths across the study site were located, tagged and genetically tested.
95 adult two-toed sloths, 32 subadults and 30 juveniles were captured and monitored for the study.
By testing for paternity and mapping the distribution of related individuals, the ecologists were able to put together the population’s mating behaviour.
The male home ranges contained an average of three females and the females usually appeared within the home range of more than one male.
The results showed that 36 percent of adult males sired offspring with at least two females, demonstrating that sloths are not monogamous.
“Because they’re highly sedentary we thought that the males most probably wouldn’t be able to vigorously defend a harem of multiple females,” Dr Zach Peery said.
But the ecologists also found evidence that the males monopolise space in certain core territorial areas, suggesting that their mating system is a complicated combination of polygyny, whereby one male monopolises many females, and promiscuity.
“They’re not necessarily just puppy dogs, they will battle and we do find males with considerable facial scars so although there is overlap and although it’s a somewhat more flexible mating system... there is structure to it,” Dr Peery said.
There are a number of benefits to promiscuous mating systems for mammals, particularly from a female point of view, he said.
These range from the female not putting all of her “eggs in one basket with one male” to the reduced risk of infanticide.
“We are suggesting that the sedentary nature of sloths could be an additional reason,” Dr Peery said.
The findings were published in the journal Animal Behaviour.