Harp Seals, Arctic Circle

Born into a world of shifting ice and relentless cold, the harp seal is a master of survival in one of the planet’s harshest and most unforgiving environments. They are best known for their heart-shaped markings on their white fur, particularly seen in pups. Adult harp seals have a shiny, silvery-grey coat with a darker, harp-like marking on their back, which gives them their name.

Found in the North Atlantic and Arctic Oceans, harp seals are uniquely adapted to life on and around sea ice. They are true cold-water specialists, relying on ice not just for breeding but also as a platform for resting and foraging. What sets them apart from other seal species is their extraordinary migration. Each year, they travel more than 3,100mi (5,000km) in large colonies between their summer feeding grounds in the Arctic and their breeding sites further south, such as the Gulf of St. Lawrence or the Greenland Sea. 

When it comes to navigating, harp seals are pretty impressive. Their adorably big, dark, tear-shaped eyes are great for seeing in low light and perfect for deep dives. Their whiskers, or vibrissae, are super sensitive and can pick up tiny vibrations in the water, helping them sense movement and direction. And their hearing gets sharper underwater, making it easier to pick up on sounds that guide them through the ocean.

Those same senses are also used for hunting, but more remarkable is their feeding flexibility. Depending on the season, harp seals will shift their diet, targeting fish like Arctic cod and Greenland halibut during summer, then switching to crustaceans and smaller schooling fish like capelin in the shallower coastal waters during winter and spring. Though not the deepest divers among seals (the elephant seal can dive 5,090ft / 1,550m), the harp seal can still reach depths of 900ft (275m) and stay underwater for around 15 minutes while foraging.

Pups are born on the ice in late winter. They are instantly recognisable by their fluffy white coats, which help camouflage them from predators. The mother stays for just 12 days, feeding the pup milk that’s up to 60% fat. In that short time, the pup triples in size — a survival necessity because the mother leaves abruptly and never returns. The pup is left alone on the ice, surviving for several weeks by living off its blubber reserves. During that time, it must learn to swim and hunt independently. Interestingly, most pups are born around the same time, boosting their chances of survival through safety in numbers.

Harp seals are vulnerable to the changing climate. As sea ice breaks up earlier each year, it puts pressure on their breeding cycle. Pups need stable ice to survive those first few weeks, but if the ice melts too soon, they can end up in the water before they're ready to swim or fend for themselves.