Image by Douglas Brown
Here’s a B&W photograph of an Alaskan Harbor Seal…
Harbor seals weigh about 24 pounds (11 kg) at birth and gain weight rapidly during a month-long suckling period; perhaps doubling their weight. They can reach five to six feet (1.5-1.8 meters) in length. Average weight for adults is about 180 pounds (82 kg); males are somewhat larger than females and can weigh up to 285 pounds (129 kg).
Harbor seals have rich social lives, manifest by play behavior close to the haul-out site. In the water, seals may play in pairs, ‘rolling’ by twisting and somersaulting over each other in continuous contact.
Harbor Seals in Alaska are not doing well, their numbers are down significantly over the last few decades. Scientists say the decline followed a dramatic shift in the kinds of fish available for seals to eat. Fat, energy-giving fish like herring, capelin, and sand lance, were replaced by low-fat, nutritionally questionable fish like pollock.
If you’re a marine mammal, high-fat prey is important to everything from warding off the bitter cold water to producing healthy milk for newborn pups. The shift in food didn’t hurt just seals. Most scientists believe it triggered dramatic declines in Steller sea lions, fur seals, and seabirds.