Which big cat has the largest canine teeth relative to skull size of any living felid?

The clouded leopard has the largest canine teeth relative to skull size of any living felid. Its upper canines can reach roughly 4–5 centimetres, an extraordinary size for a cat that is much smaller than a tiger, lion, or leopard.

This unusual dentition gives the clouded leopard a sabre-toothed appearance, although it is not a true sabre-toothed cat. Its skull is long and low, and the animal can open its jaws exceptionally wide. Those features help it deliver a powerful bite to prey, including monkeys, deer, and wild pigs.

Clouded leopards are not simply small leopards. They belong to the separate genus Neofelis and are part of the pantherine cat lineage, alongside tigers, lions, jaguars, and true leopards. Genetic studies also distinguish the mainland clouded leopard from the Sunda clouded leopard of Borneo and Sumatra. The famous tooth comparison concerns proportional size, not absolute length: a tiger’s canines are larger overall, but the clouded leopard’s are remarkable for its skull and body.