As we get older our senses fade. It’s a fact of life – our eyesight dims and we have to wear glasses, and our hearing gets worse too. By the time we’re in our 60s most of us can no longer hear very high pitched or very quiet sounds. In worst case scenarios we may have to resort to hearing aids. But there are some animals who seem to retain their hearing into old age – the birds.
We’ve long known that starlings can hear just as well in their later years as in their youth. A new study has found that the same is true of barn owls. Seven tame owls were taught to fly to a perch when they heard a particular sound and they would be rewarded with some food. The volume of the sound was adjusted to find out how well the birds could hear. What the researchers discovered was that the oldest owl, aged 23, had hearing just as good as the youngest. When you think that barn owls live to just 4 years-old in the wild, 23 is a venerable age to reach!
So, what is the barn owl’s secret? How can it maintain its sense of hearing well into old age when we cannot? It’s all down to regeneration. Many animals can regenerate. Some invertebrates can grow new limbs if one is lost and certain lizards can regenerate tails too. In the ‘higher’ animals, like birds and mammals, this cannot be done – or can it?
It seems that owls and starlings (possibly all birds) can grow new cells in their inner ears to replace any that have died off. Mammals can’t do this. We lost our regenerative powers somewhere along the evolutionary tree. But perhaps the birds held onto theirs – at least, to some of them.
So, what use is this information to us? Well, if we can find out the genes responsible for regeneration then who knows? Perhaps one day we’ll be able to grow new inner ear cells of our own and so reduce the need for hearing aids. There is a lot we can learn from nature. Many of the medicines we use come from plants and a good deal of our engineering is inspired by the works of nature. Yet another reason why we should take care to protect the natural world.
If you are interested in owls by the way, you might like to play this quiz. It’s all about falcons, owls and swifts and is one of our 60+, free-to-play nature quizzes. Go on, give it a go!