Calls of Nature: Animals Sounds Similar to Human Language

Plenty of animals, like whales and wolves, have their own distinct calls of nature, and new research suggests that these sounds contain more human-like language structure than previously thought.

The study, published in the journal Proceedings of the Royal Society B, found that the vocal sequences produced by birds seem to be generated by complex statistical processes, much like human language.

Many species of animals produce complex vocalizations, like the mockingbird, for example, which can mimic over 100 distinct song types of different species. However, though such sounds may seem human-like, proving such is difficult.

The researchers analyzed the sounds of seven different species of birds and they found no evidence of the "Markov process" - a sequence of animal calls generated by a simple random process that most scientists assume exists in animals.

Aside from birds, the researchers also analyzed the vocal sequences of chickadees, finches, bats, orangutans, killer whales, pilot whales and hyraxes, which revealed that the sequences are more complex than the simple Markov process and more akin to human language.

Human language uses what's called "context-free grammars," whereby certain grammatical rules apply regardless of the context, whereas animal language uses simple or "regular" grammar, which is much more restrictive.

"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 this gap," lead author Arik Kershenbaum, a postdoctoral fellow at the National Institute for Mathematical and Biological Synthesis, said in a statement.

The findings suggest that at some point during the course of evolution when humans diverged from animals, there is an intermediate step that can explain the likeness between animal and human language.

Uncovering the process underlying vocal sequence generation in animals may be critical to our understanding of the origin of language," Kershenbaum added.