Problem toxic toads leg it in Oz

A toad which was brought to Australia 70 years ago to control pests is becoming the biggest pest of all.

Scientists have found the legs of the toxic cane toad have got longer so the amphibian can take over more land - destroying native creatures as it goes.

The fat, ugly toads can travel up to 1.8km a night - with the ones with the longest legs getting the furthest.

Scientists say the toads, which inhabit an area 48 times the size of Wales, are "an ecological nightmare".

Click here to try our amphibians quiz

Scientists studied the movement of toads in Australia's Northern Territory for 10 months.

Cane toads originally come from South America Cane toads (Latin name Bufo marinus) can weigh up to 2kg They are toxic and spread quickly They are spreading at a rate of more than 50km a year They can live for 15 years in the wild Females lay 4,000 to 36,000 eggs at least twice a year

They discovered that the toads were moving incredibly quickly, covering distances about five times faster than when they arrived in 1935.

They say this is because the toads' legs have got longer - letting them cover longer distances quickly.

The scientists say the toads are killing many native creatures including snakes, monitor lizards and mammal predators, which are poisoned after eating their toxic skin.

So far, scientists have been unable to find a successful way of controlling the ever-spreading invaders, which are now on the brink of invading Darwin.

Chat about animals