Grey Shark

These sharks are capable of killing and feeding upon an adult reindeer if it swims where they are hunting, and it's one of the largest species of shark.  It usually grows to between 2.4 and 7 meters (7.9 and 23.0 ft) long and weighs between 400 and 1,400 kg (880 and 3,090 lb).  Coloration can range from pale creamy-gray to blackish-brown and the body is typically uniform in color, though whitish spots or faint dark streaks are occasionally seen on the back.  They utilize their cryptic coloration, and approach prey undetected before closing the remaining distance, expanding their buccal cavity to create suction, drawing in prey. This allows them to have whole carcasses in their body.

As an ectotherm (cold blooded mammal) living in a just-above-freezing environment, the shark is sluggish and slow-moving, with the lowest swim speed and tail-beat frequency for its size across all fish species, which most likely correlates with its very slow metabolism and extreme longevity.  It swims at 1.22 km/h (0.76 mph), with its fastest cruising speed only reaching 2.6 km/h (1.6 mph).