Dolphins

They have two unique hearing types. They see equally well both in water and in the air - this ability has not yet been solved either. Dolphins are very fast animals - they reach speeds of up to 55 kilometers per hour. They are exceptionally intelligent.

Adult dolphins reach sizes from 1.2 m in length and weight from 40 kg (river dolphin) to 9.5 m and 10 tons (killer whale). The brain is the largest organ in the dolphin's body. During sleep, a part of the brain is awake, allowing the dolphin to breathe in sleep so as not to drown! The life of a dolphin is directly dependent on access to oxygen.