Siberian tigers are massive animals. A fully grown male can weigh up to 300 kilograms - heavier than three adult people - and measure nearly 3.5 metres from nose to tail tip. Their thick fur has two layers: a warm undercoat and longer outer fur to keep off wind and snow. Their paws are so wide that they act like natural snowshoes, helping the tigers pad quietly across deep snow.
These tigers are solitary hunters, which means they usually live alone. They are patient and silent when stalking prey such as deer, wild boar and elk through the forest. A tiger can leap forward up to eight metres in a single bound - about the length of a school minibus. They mostly hunt at night, using their excellent eyesight to see clearly in the dark.
Siberian tigers were once very rare because their forest habitat shrank and they were sometimes hunted. Today, careful protection has helped numbers recover and there are now around 500 wild Siberian tigers. Russia created large protected nature reserves where tigers can live safely. Scientists track individual tigers using camera traps - cameras hidden in the forest that take a photo when an animal walks past - and every tiger can be recognised by its unique stripe pattern, just like a fingerprint.