The flightless bird was the only cassowary in the Delhi zoo for the last 20 years. (Representational)

The Delhi zoo's last cassowary -- a native of Australia and New Guinea known as the "world's most dangerous" bird -- has died last month, an official said on Tuesday.

The flightless bird was the only cassowary in the Delhi zoo for the last 20 years, the official said. "There are only four-five such birds in zoos across the entire country."

The death of the male cassowary occurred in June due to natural reasons, the official said.

It is the second heaviest bird in the world after the ostrich. On an average, the cassowary weighs around 60 kilograms and is 1.5-1.8 metres tall.

The large bird, which is found in the humid rain forests of New Guinea and northeastern Australia, is considered very aggressive and reclusive.

The three-toed feet of a cassowary have sharp claws with which it sometimes kick humans and animals.

In April, a male cassowary killed its owner using its long claws when the man fell on his farm in Florida, United States.