Siberian tigers are the largest cats on Earth, growing up to 11 feet long and weighing as much as six adult humans.

The Siberian tiger (Panthera tigris altaica) is the largest of the nine tiger subspecies. According to the World Wildlife Fund (WWF), adult males can measure up to 11 feet (3.3 meters) from nose to tail tip and stand 3 feet (1 meter) tall at the shoulder. They are significantly larger than their Bengal cousins due to Bergmann's rule, which states that animals in colder climates tend to have larger bodies to conserve heat.These apex predators are primarily found in the Birch forests of eastern Russia, with small populations in China and North Korea. A 2005 study by the Wildlife Conservation Society (WCS) noted that their thick winter coats can grow up to 20 inches (50 centimeters) long on the belly to protect them from temperatures as low as -40 degrees Fahrenheit. They also possess a layer of fat along their flanks and belly that acts as thermal insulation against the frozen ground.Their physical adaptations are highly specialized for the taiga environment. Their paws are exceptionally large and padded with fur, which distributes their weight to prevent them from sinking into deep snowdrifts. Despite weighing up to 660 pounds (300 kilograms), they are incredibly agile hunters. They require roughly 20 pounds of meat per day to maintain their energy levels in the harsh Siberian climate.