Unusual footage shows a 'gray whale' taking an unusual swim into the Ballard Locks near Seattle, Washington - puzzling onlookers and drawing speculation it may be unwell.

The reportedly emaciated whale spent hours in the busy Seattle waterway. Tens of thousands of grays migrate this time of year from Mexico to Arctic waters but this route into the City's crowded locks is unusual. The filmer said: "this suggests the animal is unhealthy and struggling."

A gray whale took an unusual swim into the Ballard Locks near Seattle Washington, exciting onlookers and catching the attention of scientists, who believe the mammal is sick.

The emaciated whale spent hours in the busy Seattle waterway. Tens of thousands of grays migrate this time of year from Mexico to Arctic waters. Some grays spend time in Puget Sound.

But this whale’s route into the locks, a popular spot for boaters and tourists, is unusual. This suggests the animal is unhealthy and struggling.