The wild horses of Sable Island are synonymous with the sandbar's mysterious, untamed, romantic image. What is it about the horses that draws people in?

"Wild and free horses — I don't think it's too much more complicated than that," said Bill Freedman, an ecology professor at Dalhousie University.

"I think some people understand that they don't belong on Sable Island but they admire the fact that once they got there they managed to survive all by themselves without the aid of people."

How did they get there?

Although a popular story is that the Sable Island horses swam ashore from one of the island's many shipwrecks, scientists say there's no genetic evidence to support that theory. In fact, historians believe the horses were deliberately introduced to the island during the 18th century.

Sable Island horse

The horses on Sable Island today are most likely descendants of animals that were seized by the British from the Acadians during their expulsion from Nova Scotia. (Bill Freedman/Dalhousie University)

The horses on Sable Island today are most likely descendants of animals that were seized by the British from the Acadians during their expulsion from Nova Scotia in the late 1750s and 1760s. Thomas Hancock, a Boston merchant and shipowner, was paid to transport the Acadians to the American colonies.

Hancock either bought or helped himself to some of the horses abandoned by the Acadians and is thought to have transported the horses to Sable Island along with cows, sheep, goats and hogs.

"They were introduced to the island and the idea was that the horses would take care of themselves, they would reproduce, their numbers would build up and periodically they could be harvested and sold at a profit," said Freedman.

"At the same time that the horses were introduced, other domestic animals were as well — but only the horses survived in the longer term."

How do they survive?

Sable Island's climate is more moderate than mainland Nova Scotia — meaning it's less hot in the summer and less cold in the winter.

Still, the conditions can be harsh and the horse population — currently thought to be about 550 — fluctuates every year.

"Last year there was probably around 80 or so foals that were born. This year we won't really know until we crunch the numbers of who survived and who didn't," said Philip McLoughlin, a biology professor at the University of Saskatchewan who is overseeing several research students on Sable Island.

Horse digging for water on Sable Island

A horse digs for fresh water on Sable Island. (Terry Hennigar/Friends of Sable Island)

"As far as cause of death, there are a number of things that happen especially later in the winter time when mortalities manifest themselves in old age — in winter storms, you can have individuals that aren't in the best of health die off."

McLoughlin said researchers are starting to see the differences in the number of male and female horses depending on where they are on the island. Food and water, for example, are especially limited on the eastern side of the island.

"The horses have to dig into the sand on the eastern side of the island to create a well and then line up to drink at these wells," he said.

"If you can imagine that you have to nurse a foal and you don't have access to water, you'll have a less chance of raising that foal than say another female on the other side of the island, with unlimited water so to speak, with the permanent water ponds."

Have the horses always been free?

After the life-saving station was built on Sable Island in 1801, many of the horses were put to work. Men patrolled the island on horseback looking for ships in distress — and the horses were also used to haul lifeboats and life-saving gear to shipwreck sites.

In the 1950s, some biologists working on Sable Island said the animals were damaging the habitats of the ecologically sensitive island and proposed they be removed. The Canadian government planned to ship them to the mainland to work in coal mines or be killed for food or their hides.

The headlines startled Canadians.

"Ponies of Sable Island destined for dog food," one newspaper proclaimed.

Sable Island horse schoolchildren letter

Once Prime Minister John Diefenbaker declared the Sable Island horses protected in 1960, schoolchildren from across Canada sent him thank-you letters. (Friends of Sable Island)

Schoolchildren across Canada began a letter-writing campaign to Prime Minister John Diefenbaker, pleading with him to stop the cull. In response, Diefenbaker amended the Canada Shipping Act — which governed access to Sable Island — and declared the horses fully protected.

"No person shall, without having first obtained written permission, molest, interfere with, feed or otherwise have anything to do with the ponies on Sable Island," reads the Canada Shipping Act.

The schoolchildren were overjoyed by Diefenbaker's decision and wrote thank-you letters.

"I think you are doing a very good thing for the horses on Sable Island," wrote one child named Paul. "Instead of the ponies being skinny they will be fat and instead of going to the glue factory they will be as free as the wind."

Since then, the horses have lived without human interference. 

Why are researchers interested in the horses?

The horses on Sable Island have never received modern veterinary care — just one of the things that excites researchers.

"The horses have been protected on the island. They've never had any antibiotics that have been administered, there's no veterinary drugs that have been applied to the horses. So this is really exciting," said McLoughlin.

McLoughlin and his students are looking into antibiotic resistance in horses and they're fully expecting to find it, even though the animals have never been given any veterinary drugs.

"If we do find it — which we expect to do — then the next question is, how does it get there? From migratory birds? From humans? How is antibiotic resistance invading itself across the globe?" he said.

"We kind of have a reference population in the Sable Island horses which is really exciting."

Should horses remain on Sable Island?

Martin Willison, a conservation biologist and the president of the Nova Scotia chapter of the Canadian Parks and Wilderness Society, said the horses on Sable Island are controversial in some circles because they're not native to the island.

Sable Island horses

Philip McLoughlin, a professor of biology at the University of Saskatchewan, says Sable Island would not exist as it does today without the horses. (Philip McLoughlin/University of Saskatchewan)

"The usual rule in maintaining the native biodiversity of islands is to remove alien species and this is a challenge for Parks Canada because Parks Canada is supposed to remove alien species from its national parks," he said.

"The question is, how do we define these horses? Because they've been there for hundreds of years. So are they alien and should they be removed? Or are they native and should be maintained and left alone to go on in a normal manner?"

McLoughlin said the key issue is that without the horses, Sable Island would not exist as it does today.

"They're the only terrestrial mammal and a large mammal at that, a grazer. Undoubtedly it's had an effect on how the island is set up. For good or for bad, the horses aren't going to go anywhere," he said.

"There's a questions there that Nova Scotians and Canadians have to ask themselves and it is: do they want the Sable Island horse? And I think overwhelmingly they would say, 'Yes.' This is a breed that is valuable, it's important to the ecosystem as it exists right now."