Scavenging species around the world are not known for being particular about their food. Whether they are northern hemisphere wolverines or sub-Saharan African spotted hyenas, for a scavenger any animal or bird carcass is a meal, but a study published recently in the journal Ecology & Evolution has found there is one scavenging exception to prove the rule: the Tasmanian devil.
Researchers from the University of NSW tracked the eating habits of 71 devils captured across seven different sites in Tasmania. They then analysed small whisker samples from each individual to discover what they had been eating. Whiskers hold stable isotopes from food the animals have consumed in the past few months. (The Veterinarian, December 2021)
Lead author Anna Lewis, a PhD candidate at UNSW’s School of Biological, Earth and Environmental Sciences, said it was a surprise to find most devils showed a preference for certain foods, such as wallabies, possums, or rosellas, rather than a generalist diet that included whatever was available.
“We were surprised the devils didn’t want to all eat the same thing, which seems to be a devil-specific habit since there are no other scavengers in the world that we know of who do this,” Lewis said.
The current theory is that because there is no competition for carcasses in Tasmania, devils can afford to be choosy, and although picky devils came in all shapes and sizes, researchers found the heaviest devils tended to be the fussiest eaters.
“If you’re a scavenger in Africa, then you’re competing with all these other predators for food, but in Tasmania their main competition is just with each other. This could mean the size of a devil is a driving factor in its choice of food, or alternatively, that specialising in certain types of food could help a devil gain weight,” she said.
Tasmanian devil populations have decreased significantly since the mid-1990s due to the fatal facial tumour disease that continues to threaten their survival in the wild, so Lewis said the study’s results might prove useful in the conservation effort.
“From a conservation perspective the findings could help us work out if we’re feeding devils the appropriate thing in captivity. There’s a long list of foods 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,” she said.
Further research will take a closer look at why devils make certain dietary choices, and if the animals select food consciously, opting for foods that other devils are not interested in, or choosing foods that are more abundant.
“Our next step is to look at why devils are tending towards certain foods, like pademelons and possums, and whether humans have a role to play in this specialisation, but in the meantime this study paves the way for future global research on specialisation in scavengers’ diets because it makes you wonder whether other scavengers, like hyenas or wolverines, would act like devils if they didn’t have other species to compete with.”
Anne Layton-Bennett