University of Saskatchewan Discovers Link Between Seals and Wild Horses

What do grey seals and Sable Island horses have in common? The University of Saskatchewan knows.

Biologists at the University of Saskatchewan have discovered new insights into the growth of wild horse populations on Sable Island, located about 175 kilometers southeast of Nova Scotia. Their findings highlight the interconnectedness of life.

A team led by Philip McLoughlin and Keith Hobson sought to understand why the wild horse population on the island has reached a record high of 450 to 550, after remaining steady at 200 to 400 for centuries.

They found a link between grey seals and the foraging habits of the horses. This research is featured in the journal Ecology and in The Scientist.

Where Land and Sea Meet

Grey seal populations are increasing, and when they have pups on the shore, they fertilize the sandy grasslands. Nutrients from the sea are helping the grass to grow, providing ample food for the horses.

"What is really interesting is that we show how the enrichment of grasses, which occurs non-uniformly on the island, then affects how the horses move around the island to eat," said McLoughlin.

"This speaks to the question of how seemingly distinct systems—ocean and land—can be interconnected by fundamental ecological relationships."

The University of Saskatchewan team suggested that more work is needed to prove the link between thriving seals and the increasing survival and population growth of the wild horses.

The next step is to try and detect sea nutrients in the tissue or hair of the horses.