Which big cat has the longest tail relative to its body size?

The snow leopard has the longest tail relative to its body size among the commonly recognized big cats.

Its tail can measure roughly 80–100 centimetres, while the head-and-body length is about 75–150 centimetres. That makes the tail exceptionally long in proportion to the animal, often accounting for around 40–50% of its total length. The tail is also thick and heavily furred.

This unusual feature is a mountain adaptation. Snow leopards live across high, rugged terrain in Central and South Asia, where a long tail helps them balance while crossing steep slopes and rocky ledges. They can also wrap it around the body or face for extra warmth while resting.

The clouded leopard is a common source of confusion because it also has a remarkably long tail and is highly adapted to climbing trees. However, “big cat” is often used narrowly for members of the genus Panthera, which includes the snow leopard but not the clouded leopard. Under that standard quiz usage, snow leopard is the canonical answer.