HALIFAX -- The last Sable Island horse in captivity -- a stocky, chestnut-coloured male with no name -- has died.

The 30-year-old animal, which was in declining health, was euthanized on the weekend at the Shubenacadie Wildlife Park, officials at the facility north of Halifax said.

"He was the last one not on the island," said Tabitha Cox, the park's head nature interpreter. "He had a female with him for quite a few years, but she passed away a few years ago."

The small, sturdy horse was the last descendant of a group removed from the island in the late 1950s and sent to three wildlife parks in Nova Scotia.

At the time, the government of then-prime minister John Diefenbaker was trying to recover from a public relations disaster that started when federal officials decided all the horses should be sold off because they were causing too much damage to the island.

When it was revealed the horses could be put to work in coal mines or killed to make dog food or glue, schoolchildren from across the country wrote to Diefenbaker, urging him to spare the "ponies."

Diefenbaker responded by amending legislation to ensure the horses would remain free of human interference, which remains the case today.

"He listened and federally protected the island and gifted the horses," Cox said in an interview.

As for why Shubenacadie's last Sable Island horse had no name, Cox said the park's policy is to refrain from naming wild animals.

"We don't want people associating them with pets, even though they are very cute and lovable," she said. "It's never a good idea to keep a wild animal as a pet."

Though the horse lived its entire life in wildlife parks, Cox said it remained a shy animal.

"He wasn't into getting groomed or petted," she said, noting the horse appeared to enjoy the company of the park's resident reindeer.

"They hung out together.... He will be sorely missed because he was quite unique."

Like his relatives on the island, this horse had a distinctly stout frame and a shaggy coat -- features that mark these horses as genetically unusual, even though their ancestors were domesticated breeds.

"Out on the island, they are pretty exposed," Cox said. "It's an isolated, stormy area and they grow this thicker coat."

Though often referred to as ponies, the animals are classified as horses, given the fact the adults are just tall enough -- at 13 to 14 "hands" (about 132 to 142 centimetres) -- to fit into that category.

The horses have also adapted to eating the marram grass on the island's sprawling dunes, even though that plant is notorious for its sharp edges.

"Their lips and teeth are stronger to deal with that," said Cox. "They're really adapted to a strange home.... That's part of the mystery and the interest -- how do those animals live out there in such an isolated spot?"

According to Parks Canada, the horses supplement their diet by eating kelp that washes ashore.

Earlier this year, a team of researchers from the University of Saskatchewan and Parks Canada said testing on carcasses revealed the horses carried unusually high levels of parasites and sand, suggesting they are tougher than most horses.

Between 400 and 500 feral horses remain on the narrow, crescent-shaped strip of land about 290 kilometres southeast of Halifax.

It's believed the original population, sent by boat to Sable Island in the mid-1700s, included horses that belonged to Acadian settlers deported from Nova Scotia by the British between 1755 and 1764.

The 42-kilometre sandbar, which has strict limits on tourism, was declared a National Park Reserve in 2013.

With increased federal protection, it's highly unlikely any Sable Island horses will ever leave the island again.

This report by The Canadian Press was first published Oct. 3, 2019.