Scavengers come in all shapes and sizes, but they have one thing in common: they eat whatever is available. At least…that’s what we thought.
Because Australian researchers have now identified a scavenger that turns out to be the exception to this rule. That can be read in the magazine Ecology & Evolution.
Tasmanian Devils
The study revolves around Tasmanian devils: predatory marsupials that are mainly found in Tasmania. They can be counted among the scavengers and based on that you would expect that they – just like wolves, hyenas and all those other scavengers worldwide – take what they can. “A scavenger’s job is to be a generalist and take what’s available,” said study researcher Tracey Rogers. Great was therefore the surprise of researchers when they discovered that the Tasmanian devil thinks very differently about this. “We’ve found that most Tasmanian devils are actually picky, selective eaters.”
The research
The researchers base their conclusion on a study of 71 Tasmanian devils from seven different areas of Tasmania. To gain more insight into the animals’ diets, the researchers analyzed a whisker from each Tasmanian devil. They focused on stable isotopes: the relationships between them provide more insight into what the animals (mainly) eat. The research shows that only 1 in 10 Tasmanian devils have a broad diet and are thus a real generalist who eats what the pot is about.
However, the vast majority of Tasmanian devils turned out to be a lot more choosy, mainly consuming either wallabies, possums or parrot-like rosellas. It points to the fact that these Tasmanian devils don’t eat what’s on offer, but specifically target foods that they actually like. And just as we humans all have our own food preferences, Tasmanian devils have them too. “We were surprised that the devils didn’t all want to eat the same thing,” said researcher Anna Lewis. “Most of them decided, ‘No, this is my favorite food’. And that certainly seems to be a behavior we only see among Tasmanian devils. There are no other scavengers on Earth that do this as far as we know.”
The Empire Alone
It naturally begs the question of why many Tasmanian devils are so picky. For now, the researchers think it has everything to do with the fact that they only have the empire in Tasmania. “If you’re a scavenger in Africa, you’re competing for food with all those other predators,” Rogers said. “But in Tasmania there are no other predators or competitors around carcasses.” And so the Tasmanian devils can afford some pickiness. In fact, they may even thrive on it. The research shows that the heaviest Tasmanian devils were usually also the pickiest eaters. It could mean that focusing on certain foods is causing the Tasmanian devils to gain weight.
Follow-up research should reveal what drives the Tasmanian devil to make certain dietary choices. In addition, it does not seem a bad idea to take a closer look at the diet of other scavengers. Because who knows, we might come across surprises again. “It’s hard to believe that a scavenger can be a specialist,” Lewis said. “It makes you wonder if other scavengers – like hyenas and wolves – would behave like the Tasmanian devils in the absence of competitors.”
Source material:
“Tasmanian devils have just broken the laws of scavenging – and scientists are puzzled– University of New South Wales (via Scimex)
Image at the top of this article: Chaim Mehlman via Pexels