Bats might not actually communicate with a Scouse accent, or any accent for that matter, but they do have an array of different dialects between colonies, just like we do. However, it’s not the dialects themselves that have scientists excited, it’s how they learn them.
There are 13,000 species of bat worldwide but this week the Eygyptian Fruit Bat has come into the spotlight because of how it learns it’s vocalisations, which could be useful in understanding how humans learn theirs. It has over a thousand vocalisations all of which essentially mean ‘get out of my way’, which is useful when you live in a packed colony of up to 50,000 members- wouldn’t want to be around there at dinner time.
Egyptian fruit bats develop their communication through ‘vocal learning’, which few other mammal groups do but it is known in humans, whales and dolphins (Check out my second blog post ‘Remixing the old with the new: How do Humpback whales learn their song?’ for more info on that!).
Unlike whales and dolphins though, bats are much easier to manipulate in a lab environment which makes them a useful study organism. Scientists from the Tel Aviv University, Israel, have done just this to investigate whether the bat pup’s vocalisations are more heavily influenced by their mothers call or by the collective noises of the colony.
They took 15 pregnant females and divided them into three groups, each were then exposed to recordings of wild bats with manipulated frequencies. At 14 weeks, after the pups were weaned, their mothers were released back into the wild. Once the pups reached 6 months old it was found that the young bats were emulating the pitch of the recordings they had grown up with.
This demonstrates that the colony wins; the effect of the colony as a whole is far greater than that of the vocalisations of the mother. It makes complete sense if you think about it as bats grow up in almost total darkness and have one of the best auditory* senses in the mammalian world, so it’s no wonder they’re influenced by all the sounds around them.
The bat pups have now been released back into the wild and it would be interesting to see whether their new sounds ripple through the rest of the colony or if they now have to adapt their calls to suit the colony’s current dialect
‘Crowd vocal learning induces vocal dialects in bats: Playback of conspecifics shapes fundamental frequency usage by pups.’ Yosef Prat, Lindsay Azoulay, Roi Dor, Yossi Yovel. Published: October 31, 2017 https://doi.org/10.1371/journal.pbio.2002556