This idea is what led the animal curator Jack Throp to attempt a de-extinction at Honolulu zoo in the 1960s. By breeding dogs with Poi-like characteristics together, and then doing the same with several generations of their offspring, he hoped to concentrate the type’s genes until it emerged from the ether of hybridisation.
“There’s a wonderful picture in the Honolulu Star where he’s recreated what he thinks a Poi dog should look like,” says Williams. Unfortunately, the project’s results are not well-documented, and not long afterwards the project seems to have died. “And again, it never really picked up traction as a popular breed and people wanting to preserve them,” adds Williams.
However, there might be more of an afterlife for the Salish dogs, which ethnographic studies suggest were sometimes intentionally crossed with wolves and coyotes to make them better hunters. Kasia Anza-Burgess, a former archaeologist who has studied the Salish people and their relationship with dogs, is optimistic that perhaps their lineage lives on somewhere in the wild.
“We didn’t find any genetic evidence [of hybridisation] in our sample [of Salish dog bones from archaeological sites],” says Anza-Burgess. But she points out that she only looked at mitochondrial DNA, which is passed from mothers to their offspring. This is significant, because – naturally – it was the female dogs that Salish people would let out to breed with wolves or coyotes, so injections of wild genes would always come from males.
“But I think it would be fascinating for future research to look at whole genomes and not just the maternal lineage, and see what kind of backcrossing you can find there, because the evidence seems pretty strong that it should be there – we just didn’t pick it up,” says Anza-Burgess.
A tricky decision
Fast-forward to today, and endangered dogs face a new obstacle on the path to survival: the collision of genetics with ethics.
In the last decade, growing awareness about low genetic diversity in many dog breeds – particularly pedigree varieties – has led dog organisations to take inbreeding more seriously.
Today some breeds have such small populations that the ethics of keeping them going becomes tricky – with such low genetic diversity, they can become more susceptible to deformities or illness. Eventually, “inbreeding depression” – where a population’s fertility is affected by the accumulation of unhealthy genetic variants – can wipe them out altogether.
One breed at risk is the Sealyham terrier, which became fashionable among celebrities in the 1930s and 40s – Cary Grant, Princess Margaret, Marlena Dietrich, Elizabeth Taylor, Bette Davis and even Agatha Christie all had one of these cuddly white dogs at one time. With their curly white fur and venerable beards, the dogs seem almost part-lamb, part old man.
But after decades of popularity, they fell into decline with the emergence of designer breeds like the cockapoo – the offspring of a poodle and a cocker spaniel – which has similarly cuddly features.
After hitting rock bottom in 2008, today their populations are steadily increasing. However, the entire breeding population is still only just over 100 – often considered the lower limit for the survival of endangered species.
Given the new focus on the genetic health of dogs, Worboys doesn’t think there’s much hope for endangered breeds like the Sealyham today. He recalls a conversation with a vet at a kennel club a few years ago, “and he was saying, off the record, there are about six or seven breeds he wished would disappear because they’re more trouble than they’re worth”.
Who knows, perhaps soon such delightful hounds as the Old English Sheepdog, the Sealyham Terrier, and the Irish Wolfhound could join the list of extinct historical curiosities, along with all the others.
Zaria Gorvett is a senior journalist for BBC Future and tweets @ZariaGorvett
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