Belugas are relatively small for whales, reaching about 4 to 5 metres in length - roughly the size of a large car. Their pure white colour helps them blend in with Arctic ice, and their thick layer of blubber (up to 15 centimetres thick) keeps them warm in freezing water. The round, lumpy forehead - called a melon - is used to focus the clicking sounds belugas use to find their way and communicate.
Belugas are extremely social animals and live in groups called pods. Pods can range from a few individuals to thousands of whales travelling together. They communicate constantly with each other using an impressive variety of sounds - chirps, squeals, clicks and bell-like tones. Scientists have recorded belugas making over 50 different types of sound, and they seem to be very playful, often rolling, chasing each other and even blowing bubble rings.
Every summer, enormous groups of belugas gather in shallow, warm river estuaries along Russia's Arctic coast. Here they rub against the sandy and rocky shallows to shed their old outer skin - a behaviour called moulting. These gatherings of hundreds or even thousands of white whales are a remarkable sight. Scientists travel to locations like the White Sea and the Anadyr Estuary to study the whales and count their numbers.