Marine mammal experts are testing tissue samples for a potential common cause of the surge in carcasses found on the state's beaches this year.

Deaths of gray and harbor seals, in much greater numbers than usual, have been attributed to viruses related to distemper and the flu.

There are plenty of seals in Unalaska, but ringed seals -- who make their homes on the ice -- are rare.

"How he got so far inland from the ocean to Route 6A without getting hurt is amazing," police posted. "Must be a NAVY SEAL!"

Unalaskans are used to spotting marine mammals around the island. But lately, they're not just seeing whales or otters. They're seeing ringed seals — an Arctic species that typically lives far north of the ice-free Aleutian Islands.

A parasite-riddled seal afraid of the water is the first Alaska marine mammal rescued in 2017. The seal will not be returned to the wild if it continues to survive rehabilitation at the Alaska SeaLife Center in Seward.