ANIMAL vocalisations have more in common with human speech than previously thought, scientists claimed today.

Research published by the Royal Society in its Proceedings B biological science journal suggests there may be a missing link between sounds animals use to communicate and the more complex linguistic abilities of humans.

“Language is the biggest difference that separates humans from animals evolutionarily, but multiple studies are finding more and more stepping stones that seem to bridge the gap,” said lead scientist Dr Arik Kershenbaum of the National Institute for Mathematical and Biological Synthesis in Tennessee, US.

“Uncovering the process underlying vocal sequence generation in animals may be critical to our understanding of the origin of language.”

It has long been recognised that some species of animals possess distinct vocabularies.

Some monkeys have a range of cries distinguishing between threats, which is useful since the evasive action appropriate for a snake attack is different from that for a bird of prey.

But linguists have so far held that animals lack the ability to use grammar to change or extend the meanings of individual sounds by reordering them.

Their vocalisations were believed to follow a structural system known as the Markov process, where sound sequences could easily be predicted by listening to a finite number of preceding elements.

The new study sought evidence of Markovian dynamics in seven species — chickadees, finches, bats, orang-utans, killer whales, pilot whales and hyraxes — yet failed to find it.

The sounds produced fitted statistical models for human language instead, the scientists concluded.