Image caption The researchers analysed teeth collected on the island

The smallest mammoth ever known to have existed roamed the island of Crete millions of years ago, researchers say.

Adults were roughly the size of a modern baby elephant, standing over a metre tall at the shoulders.

Remains were discovered more than a century ago, but scientists had debated whether the animal was a mammoth or an ancient elephant.

A new analysis of the animal's teeth suggests it falls closer to the mammoth lineage.

Palaeontologists Victoria Herridge and Adrian Lister, from London's Natural History Museum, report their findings in the Royal Society journal Proceedings B .

"Dwarfism is a well-known evolutionary response of large mammals to island environments," said Dr Herridge.

This evolutionary phenomenon is thought to be driven by the relative scarcity of food sources or by the absence of predators.

"Our findings show that on Crete, island dwarfism occurred to an extreme degree, producing the smallest mammoth known so far," she added.

The teeth analysed in the study were originally collected by fossil hunter Dorothea Bate in 1904. They were first thought to belong to dwarf forms of the straight-tusked elephant Palaeoloxodon antiquus, which is considered the evolutionary ancestor of all dwarf elephants.

But comparisons with other ancient elephant and mammoth species suggest it was more closely related to the latter, assigning it to the species Mammuthus creticus.

They suggest the mammoth could have reached the island as early as 3.5 million years ago.

The team also used an upper foreleg or "arm" bone to estimate the mammal's size.

"The arm bone in particular gives us the best evidence so far for how big - or rather, how small - this dwarf mammoth really was," said Dr Herridge.