Camera traps set up in the Strzelecki Desert of South Australia captured some unusual behaviour among the region's dingoes last year: despite other food options, the wild dogs were recorded engaging in cannibalism.
The surprising discovery was made by ecologist Paul Meek from the Department of Primary Industries' Vertebrate Pest Research Unit – and it's the first time that camera traps have ever recorded such behaviour.
While dingo control measures stir up much debate among Australia's scientists, the country's largest land predators continue to be eradicated in some areas due to the threat they pose to livestock and some native species. Meek had been testing out a new, more humane, trap that captures and euthanizes the dogs when he made his cannibalism discovery.
After catching a dingo late at night, Meek opted to leave the carcass in place until the morning. "When I returned, it was absolutely decimated – there was just a trail of intestines," he tells New Scientist.
To find out what night-time scavenger had eaten the dead dog, Meek set up cameras near his trap and ended up with a surprising answer: other dingoes had devoured the remains. Camera traps at other carcasses recorded similar behaviour, with hundreds of visits by numerous dogs. Meek even observed dingoes aggressively approaching trapped but still living dogs (though they were seen eating only those that had already died).
Dingoes' eating habits have long been the source of their bad reputation. Their appetite for livestock has seen the dogs poisoned and shot for centuries, and they've been shut out from vast stretches of land by a 5,500-kilometre dingo-proof fence. The opportunistic hunters are also known to prey on vulnerable native species like koalas and wallabies, and have even been blamed – likely unfairly – for the extinction of the thylacine through hunting competition.
Today, however, many experts believe the dogs should be protected. As Australia faces an extinction crisis, these efficient hunters can play an important ecological role, they argue, by controlling much more destructive pests that gobble up native wildlife – like feral cats and invasive red foxes.
Meek has spent years studying Australia's pest animals, as well as the use of remote cameras in monitoring wildlife, but this is the first time that camera traps have recorded cannibalism in dingoes. And it begs the question: why eat your own species?
Some animals do resort to eating their own kind in times of stress or during a food shortage, and when wildlife ecologist Benjamin Allen witnessed dingo cannibalism during a drought in 2009, the lack of food seemed like an obvious explanation. But in Meek's research area, the dingoes were well fed – so why eat other dogs?
A quick look at other corners of the animal kingdom reveals plenty of explanations for cannibalistic behaviour. In some frogs and salamanders, newborn larvae or tadpoles will eat other young or eggs of the same species. Some sharks infamously partake in "intrauterine cannibalism", where unborn sharks eat their sibling embryos in the womb. These behaviours might seem grisly, but they help the young animals get a head start on gaining necessary nutrients, with the added bonus of taking a bite out of future competition. In fact, some young animals get their early boost of energy by eating their parents – or parts of them (say hello to the caecilians).
And let's not forget the femmes fatales of the mantis and spider world. Eating your mate can provide a convenient source of nutrition for a female who's about to devote plenty of energy to producing offspring, and in some species of spider, males who make the ultimate sacrifice actually produce the most offspring!
Cannibalism clearly has its uses. In the case of the dingoes, Meek suspects the high density of dogs in the area meant the carnivores couldn't be too choosy with their food. In an area full of competition, it's not a good idea to pass up an easy meal – even if that meal looks a whole lot like you.
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Top header image: Klaus Stiefel, Flickr
Animal Behaviour
Animal Behaviour
Fossils
