Belugas (Delphinapterus leucas) are odd-looking creatures. They have flexible necks that can move up and down and side to side, allowing them to nod and turn their heads. The 'melon' on their head becomes bigger as they get older and can change shape.
In the depths of the winter, when the ice cover is almost total, belugas keep breathing holes open by crowding together in one spot to swim in a constant rolling mass. This makes them easy targets for polar bears and they are usually covered with scars from bear attacks. Belugas 'talk' a lot, making all sorts of tweeting, clicking and squeaking noises, earning them the nickname 'sea canary'.