Why tiny 19ha Aussie island is home to 400 deadly snakes

If the thought of snakes makes your skin crawl, a tiny island off the coast of Perth could be your worst nightmare.

Carnac Island is just 19 hectares in size and home to hundreds of deadly tiger snakes.

With no predators on the island, the population of 400 snakes is thriving and has adapted to living off a very small supply of fresh water.

"I don't recommend anyone coming over here actually plays with them because they are essentially the fifth deadliest snake in the world," Animal Plant Mineral biologist Dr Mitchell Ladyman told 9NEWS.

But no one knows how the snakes ended up on the island.

The most prominent theory is a travelling snake showman Rocky Vane dumped his snakes on the island after his wife was bitten and died.

"It was about 1930 when Rocky Vane found himself in all sorts of trouble with the police," Dr Ladyman said.

"He had to get rid of his population of tiger snakes he had, which was about 40 adults."

Even weirder - most of the snakes on the island are blind because seagulls have pecked out their eyes when they feed on chicks.

The island is 10 kilometres off Fremantle, and is home to other wildlife including sea lions.

"In terms of island snakes, this is probably one of the densest populations in the world," Dr Ladyman said.

The venomous reptiles can be hard to spot, but visitors to the island are urged to be careful.

"We do have signage along the eastern beach, and the other side of the island as well, that indicate the snakes are there," Melissa Evans from the Department of Biodiversity, Conservation and Attractions told 9NEWS.

"Hopefully people heed our warnings and don't go up to the vegetation without any shoes on."