Fussy Tassie devils break scavenger mould
Tracey Ferrier |
Tasmanian devils have broken the mould on what it means to be a scavenger, with researchers discovering they are actually very fussy about their food.
Scavengers the world over are known to be opportunistic eaters that will eat whatever they find, wherever they find it.
But devils have set themselves apart. An analysis of their whiskers, which hold chemical imprints from the things they have eaten, has shown they have individual tastes and preferences, just like humans.
“It’s a scavenger’s job to just be a generalist and take whatever it can find,” says University of NSW Science Professor Tracey Rogers, senior author of the study.
“But we’ve found that most Tasmanian devils are actually picky and selective eaters. They’ve broken the laws of scavenging.”
The leading theory is that devils have become fussy eaters because of where they live.
“If you’re a scavenger in Africa, then you’re competing with all these other predators for food,” Prof Rogers says.
“But in Tasmania, there aren’t other predators around, or competition for carcasses. Their main competition is just with each other.”
The study also revealed something else – the biggest devils tended to be the fussiest about what they dined on.
This could mean the size of a devil is a driving factor in its choice of food, or that specialising in certain types of food could help a devil fatten up.
The study analysed whisker samples from 71 devils captured at seven different sites across Tasmania.
The results showed just one in 10 devils had a generalist diet, made up of whatever food was available and convenient.
The vast majority chose to dine mostly on their favourite foods, whether it be wallabies, possums or rosellas.
“This definitely seems to be a devil-specific habit,” says Anna Lewis, the lead author of the study who is also a researcher at The Carnivore Conservancy.
“There are no other scavengers in the world that we know of who do this.”
Devil numbers have plummeted since the 1990s, when the highly contagious and often deadly devil facial tumour disease started spreading in wild populations.
When infected devils import the disease into their colonies, it is probably about 77 per cent of the population will be dead within five years.
As a result, many conservation groups have tried to minimise the spread by keeping some populations in captivity until it is safe to release them.
Ms Lewis says her study should help keepers provide the devils with the best care in the meantime.
“The findings could help us work out if we’re feeding devils the appropriate thing in captivity,” she says.
“At the moment, there’s a long list of foods that devils can eat, but it’s not specific in how often they eat all those foods or whether most only focus on a few different food types.”
Ms Lewis completed the study as part of her PhD and captured, handled and obtained whisker samples from most of the devils.
She does not mind admitting she has a favourite, named Arcturus after one of the brightest stars in the sky.
He prefers a diet of pademelon and wallaby but every now and again will branch out and indulge in a bit of snake.
The study has been published in the scientific journal Ecology & Evolution.AAP