The New Guinea singing dog is one of the oldest and rarest dog breeds in the world. It’s believed only 200 to 300 specimens are alive today, all of which are found in conservation centers. None have been seen in the wild since the 1970s. But a new genetic study found that another rare dog breed, the Highland Wild Dog, is essentially the same breed as the New Guinea singing dog, showing that this population isn’t actually extinct in the wild.

Our motivations were to see if this population of Highland Wild dogs, which had been identified by a previous expedition in 2016, were, in fact, the rare and supposedly extinct in the wild New Guinea singing dogs,” Elaine Ostrander, National Institute of Health (NIH) Distinguished Investigator and senior author of the paper, told ZME Science.

“Having nuclear DNA gave us the opportunity to look at the genomes of these dogs and figure out what they were and where they came from,” she added.

A canine tune lost in the wild

New Guinea, the second largest island on Earth, is divided into the independent Papua New Guinea and the Indonesian-controlled West Papua. New Guinea singing dogs prefer sparsely populated areas in vast, thickly forested areas, which makes them extremely elusive. In fact, they’re so rare that some researchers believe Singers are now extinct in their native habitat of Papua New Guinea.

Aside from being rare and thought extinct in the wild, New Guinea singing dogs are pretty unique due to a number of features not found in modern dog breeds. Their spine is very flexible, almost cat-like so that they can actually climb trees in order to hunt birds, rabbits, and other prey. Their drive for predation is so strong that they can’t help themselves when they sense anything remotely resembling their favorite prey. So don’t let the fact that virtually all Singers have been raised in captivity fool you — they are by no means domesticated animals. Nor are Highland Wild Dogs.

“The Highland Wild Dogs are shy dogs. They’re not easily photographed or frequently seen. These three dogs that we were able to sample were in an area around a gold mine and they might have been attracted to come down because of food, for instance. But by and large, they stay at higher altitudes and further in,” Ostrander said.

Of course, the most defining feature of New Guinea singing dogs is their unique vocalization ability, which makes their howls sound like they’re singing. Sometimes, when more Singers howl together, it can sound like a chorus.

Curious to hear what they sound like? Turn your volume down a notch and hit play below.

“They do have this harmonic, melodic sound that they make and that really distinguishes them from any other mammal on the Earth. It’s unusual, it’s pleasing,” Ostrander said. “It’s not clear why it evolved and it stayed. You can always speculate it’s a mating thing, but we don’t know that, honestly.”

“One of the most important things about these dogs is that they’re one of the only populations of actual wild dogs in the world. We have these Highland Wild dogs and we have dingoes. Most other dogs are just sort of feral domestic dogs and things like that. It’s kind of a very interesting group in that way. Are these dogs that have never lived with people or was it actually thousands of years ago they actually lived with people and have reverted to being wild? These are interesting questions when looking at these particular groups,” Dr. Heidi Parker of the National Human Genome Research Institute (NHGRI), who led the genomic analyses, told ZME Science.

Although virtually no Singers have been spotted in the wild for decades, on the Indonesian-side of the island, researchers have been able to capture and collect samples from 15 Highland Wild Dogs during 2016 and 2018 expeditions led by the New Guinea Highland Wild Dog Foundation. Blood samples from three individuals were used in the new study to sequence the Highland Wild Dog nuclear genome.

Two peas in a pod

Highland Wild Dogs are very physically similar to Singers and are believed to be even older than the New Guinea singing dogs. In fact, some believe that the Highland Wild Dogs is the direct ancestor of the New Guinea singing dog.

This hypothesis has been difficult to prove, until recently when researchers from NIH and NHGRI compared the genomes of both breeds, which are considered the oldest in the world.

Not surprisingly, the researchers found that the two breeds have very similar genetic sequences. Although their genomes aren’t identical, they much more closely resemble each other than any other canid known.

“In the tree of life, this makes them much more related to each other than modern breeds such as German shepherd or bassett hound,” Parker said.

“What we did is we looked at genetic markers on these dogs and compared them to a bunch of modern breed dogs, as well as village dogs from the area, and dingoes, and determined which ones they were most closely related to.”

“We found that Highland Wild Dogs had a lot in common with Papua New Guinea singing dogs, as well as the dingoes from Australia. Most importantly, the New Guinea singing dogs were most closely related to these Highland Wild Dogs.”

According to the researchers, the genomic similarities between the New Guinea singing dogs and the Highland Wild Dogs suggest that we’re dealing with the same breed.

Since all New Guinea singing dogs have been raised in captivity, there’s been a lot of inbreeding that reduced variations in the group’s DNA. But, essentially, the Highland Wild Dogs are the wild and original population of New Guinea singing dogs, this new study suggests. It’s just that the latter lost the genetic variation present in the wild population due to inbreeding.

“That would be expected because the conservation of the dogs only derived from eight or nine dogs and they’ve been inbred. And we do see about 30% of the Highland Wild Dog population is not seen in the captive New Guinea singing dog. What we don’t know is whether that 30% represents the original New Guinea singing dog-ness or is it a bit of admixture from the village dogs and things like that. We know it’s not very much if it is,” Ostrander said.

“Our conclusion is that these Highland Wild Dogs represent the predecessors to the New Guinea singing dogs that are in conservation centers today”

Breeding specimens from both captive and wild populations could thus replenish some of the genome sequences that have been lost in Singers. This way, researchers hope to regenerate a genuine New Guinea singing dog population as they might have looked like hundreds of years ago.

Another important finding worth mentioning is that both New Guinea singing dogs and Highland Wild Dogs have unique genomic variants found nowhere else in other dogs that we know today.

This may be important for research investigating the history of dog domestication.

“Another interesting result that came out of this is that when we looked at the DNA of Highland Wild Dogs grouped closely with the dingoes as well. They broke off apparently on a branch very early on before all the modern dogs from Western Europe that you see around the dog park. So, they represent a very early event in the evolution of dogs. That was unexpected and very cool!” Ostrander added.

But since New Guinea dogs split a long time ago from the common ancestor of modern breeds, the researchers would need a whole-genome sequence, not just the nuclear genome to find those unique sequences that may reveal instances in the timeline of canine domestication. That’s something that the researchers are working on now.

And since Singers are so talented at vocalization, their genome might help shed more light on how vocalization and its deficits occur.

“They make this noise unlike any other mammal. It isn’t like listening to your chihuahua singalong ‘happy birthday’. It’s really a very different sort of thing. I’m actually curious what the underlying genetics is. It’s one of the reasons I’m excited we’re doing whole-genome sequencing of these animals,” Ostrander said.

Scientists mostly rely on birds to look for clues about complex vocalization outside humans and other primates. Having another mammalian species that is a talented singer could greatly advance research into the genetic underpinnings of vocalization and perhaps lead to new treatments for human patients who are deficient in this respect.

“I think one of the most important things about this study is that it may offer some opportunities for conservation biology. We know that captive populations are pretty inbred and here’s this great example of a more outbred population of essentially the same thing. So, having an opportunity to contribute to the restoration of the species would be really exciting. That’s something that real conservation biologists I know will look into,” Ostrander concluded.

The findings appeared today in the Proceedings of the National Academy of Sciences.