Barn owls have exceptionally good hearing, which helps them locate small prey scuttling about in the grass at night—and their sharp ears may not change as they age. As Helen Briggs reports for the BBC, a new study shows that barn owls, unlike many other animals, maintain their excellent auditory senses well into old age.
A team of researchers trained seven hand-raised barn owls to sit on a perch and fly to a second perch when they heard auditory cues. The birds were then divided into two groups: three owls that ranged in age between 13 and 17 were deemed the “old barn owls,” while four owls younger than two years of age were labeled the “young barn owls.” (In case you were wondering, and we know you were, two of the old owls were named Bart and Lisa.)
The scientists played the owls sounds at different frequencies, ranging from levels inaudible to humans, to sounds resembling a soft whisper, according to Giorgia Guglielmi of Science Magazine. If the birds flew to the target perch in response to the cue, they were given a snack from an automatic feeder.
Both young and old owls were able to respond to the varying levels of auditory cues. According to the study, which was published in Royal Society Proceedings B, the researchers found that there was no statistically significant difference between the two age groups in the study. For good measure, researchers also tested the hearing of a barn owl that had lived to the ripe old age of 23. It appeared to hear the sound signals just as well as the other owls.
Why were the barn owls able to maintain such acute hearing throughout their lives? As Helen Thompson of Science News explains, birds are able to regenerate tiny hair cells that line sensory portion of the eardrum. Other species—including humans—cannot re-grow these cells, which is why they suffer from hearing loss as they get older. In fact, by the time humans reach the age of 65, they typically lose more than 30 decibels in sensitivity at high frequencies. Age-related hearing loss has also been observed among chinchillas, mice and gerbils.
The authors of the study hope to conduct further investigations into the mechanism that allows barn owls to maintain “ageless” ears, as they put it, which could lead to new treatment options for hearing-impaired humans. Until then, they write, we humans “can only regard this capability of birds with great respect (if not with envy).”