A startling discovery: Commonly believed to be a breed of wild dog, scientists now consider the dingo to be a species in its own right. Photo: Neil Newitt
When you look at the picture above, what do you see? A wild dog? A strangely colored wolf? Or something entirely different: a dingo? For centuries, scientists have debated whether Australia’s native canine is its own species or merely a type of wolf or dog. Now, based on physical and genetic evidence, a team of scientists is making the case that the dingo is a unique species that deserves protection under Australia’s federal conservation laws. If they can’t convince governments and landholders, the dingo may be doomed.
Wild dingoes live across Australia, in grasslands, deserts, and even wetlands and forests. Archaeological evidence suggests that the animal arrived on the continent at least 3500 years ago as people sailed back and forth from Asia, where it first appeared, then continued to evolve in isolation until the arrival of Europeans and their dogs in the late 18th century. The European naturalists who first heard descriptions of the dingo believed it represented a new species of canine and gave it a species name to match: Canis dingo. Domesticated dogs, on the other hand, are known as Canis lupus familiaris, indicating that they are a subspecies of wolf (Canis lupus).
But over the next 300 years, scientists began to argue about what to call the dingo, given the lack of early physical specimens and the fact that the original classifications were based on nothing more than a painting and description given by Australia’s first governor, Arthur Phillip. Dingoes have continued to change as they bred with settler dogs. Today, Australia’s native canine is most often referred to by scientists as C. lupus dingo, relegating it to a subspecies of wolf based on a notion that dingoes evolved from wolves in Asia. Recent studies suggest that dingoes, dogs, and wolves are cousins, all descended from a distant ancestor.
That classification left University of Sydney wildlife biologist Mathew Crowther unsatisfied, given his experience studying wild dingoes. He believed that conservation and management decisions were not being based on firm evidence. “A dingo is a distinctive thing in Australia,” identifiable by its erect ears, bushy tail, and neck that can arc backward into prime howling position, he says. Still, it’s difficult to tell a dingo from a dingo-dog hybrid, or even a feral dog, because natural variation within dingoes is poorly understood and mating with wild dogs may have altered the genome of living dingoes, Crowther explains.
Being able to define what a dingo is—and isn’t—is increasingly important in Australia. While some scientists argue that dingoes with no dog DNA fill the important niche of apex predator in Australia’s ecosystem by eating feral cats and foxes, ranchers lump dingoes, feral dogs, and dingo-dog hybrids into the category of pests that attack and kill valuable livestock. Current policies in some jurisdictions of Australia aim to exterminate dingo-dog hybrids while conserving dingoes. But without a clear definition of what distinguishes a dingo, it’s hard to manage wild dingoes, dingo-dog hybrids, and free-roaming domestic dogs, says Damian Morrant, an ecologist with James Cook University, Cairns, who was not involved in the new study. He says the work is a “baseline” for developing clear guidelines for identifying dingoes in the wild.
To begin sorting dingo from nondingo, Crowther and his colleagues at the universities of Sydney, New South Wales, and Western Sydney reviewed genetic work conducted by other researchers and began tracking down pre-1900 dingo specimens, which would allow them to study the species before it encountered—and mated with—domestic dogs brought by European settlers. “One of our colleagues went to all the European [natural history] museums: London, Paris, Germany, Oslo,” Crowther explains. The team discovered a range of coat colors on dingoes preserved in the museums: yellow, brown, ginger/red, black, and white. That indicated that these colors are not the product of recent mating with dogs, and that animals boasting them today can be considered pure dingoes.
The researchers also compared the skulls of the dingo specimens with those of wolves and similar-looking domestic dogs such as Australian cattle dogs and collies. While there were overlaps, the dingoes had wider and shorter skulls and no hind leg dewclaws, vestigial toes that don’t touch the ground, which are common among dogs and wolves, the team reported online this week in the Journal of Zoology. Based on these physical and genetic differences, the researchers propose changing the dingo’s scientific name back to Canis dingo, once again classifying it as its own species.
Given the contentious attitudes about dingoes as either top predators or pests, as well as the uncertainty among scientists about their evolutionary past, the paper will “inflame passions across the board,” says Christopher Dickman, a conservation ecologist at the University of Sydney who is not part of the team. And so it has. Although J. William Ballard, an evolutionary geneticist at the University of New South Wales in Sydney, says the study provides a “road map for the debate,” he believes the methodology is weak and the data unconvincing. Still, dingo specialists such as Christopher Johnson, a conservation biologist and ecologist at the University of Tasmania, Sandy Bay Campus, welcome the work. “It places the dingo on firmer biological ground as a distinct [group],” he says.
Crowther and his colleagues acknowledge that they’ve not yet identified “consistent and clear diagnostic features” that characterize all members of C. dingo, but they claim they’ve set limits on physical traits of the species. And for conservation and land managers that’s a start, says Euan Ritchie, an ecologist at Deakin University, Melbourne Burwood. “If it looks like a dingo, smells like a dingo, and acts like a dingo, is that enough” to count it as a dingo?
Access to the paper: http://onlinelibrary.wiley.com/doi/10.1111/jzo.12134/abstract