It is so rare, it has happened a mere 15 times in 100 years: the sighting of a white harbor porpoise.
On June 8, the porpoise was spotted near Denmark in the Baltic Sea by a layperson who caught the animal on camera. "This is an extraordinary sighting," says Fabian Ritter, marine biologist with the organization Whale and Dolphin Conservation (WDC), which received the incredible footage.
And not only was the sighting extraordinary in itself, says Ritter, but the marine mammal's behavior was equally exceptional.
"This animal appears to be playing with the vessel, swims alongside it and rides the bow wave. That is quite unusual behavior for a harbor porpoise," says Ritter. "I'm not saying it's impossible," he adds, "but they are usually a wary species, and not especially interested in vessels. This is quite curious behavior."