Why do parrots live so long?
Scientists knew that large birds and parrots live long lives, but now a new study reveals the mystery of parrot longevity.
Researchers at the Max Planck Institute of Animal Behaviour and the Max Planck Institute for Evolutionary Anthropology in Germany studied 217 parrot species (half of the known species of parrots), such as the Scarlet Macaw (Ara macao) in South America and the Sulphur-Crested Cockatoo (Cacatua galerita galerita) in Australia. They published their results in March 2022 in Proceedings of the Royal Society B.
Large birds have an average lifespan of about 30 years, and so do parrots. The researchers found that large brain size has led some species of parrots to live long lives. This is the first study that links brain size, and increased cognitive ability (intelligence), to longer lives in parrots – because they are able to reduce their environmental threats that would otherwise kill them.
Researcher Simeon Smeele from the Max Planck Institute of Animal Behaviour said that the problem has been sourcing good quality data because it is only possible to compare living parrots: ‘Comparative life-history studies require large sample sizes to provide certainty, because many processes are at play at once and this creates a lot of variation.’ So, the researchers teamed with Species360, which has animal records from zoos and aquaria from around the world. Together, they had data from over 130,000 individual parrots from over 1,000 zoos.
The findings showed a wide diversity of lifespans in parrots, ranging from an average of 2 years for the Fig Parrot and up to 30 years for the Scarlet Macaw and 25 years for the Sulphur-Crested Cockatoo.
‘Living an average of 30 years is extremely rare in birds of this size,’ says Simeon Smeele. ‘Some have a maximum lifespan of over 80 years, which … is really spectacular if you consider that human males weigh about 100 times more than a parrot.’
The researchers also examined two hypotheses: 1) having relatively larger brains enable longer lifespans (i.e. smarter birds can solve problems in the wild, thus preventing their early death), and 2) having relatively larger brains take longer to grow. So, they collected information on brain size, average body weight, and developmental factors.
They found that increased brain size has enabled parrots to live longer lives. Larger brains make parrots more flexible in their thinking. ‘For example, if they run out of their favourite food, they could learn to find something new and thus survive,’ says Simeon Smeele. They found that diet or greater developmental time to grow a larger brain did not lead to longer average lifespans.
In the future, the researchers plan to study whether sociality and cultural learning in parrots might have also contributed to their long lifespans. ‘Large-brained birds might spend more time socially learning foraging techniques that have been around for multiple generations. This increased learning could potentially also explain the longer lifespans as it takes more time but also makes the foraging repertoire more adaptive,’ says Simeon Smeele. Humans are special because they have social skills, so the researchers want to test the same factors in parrots. ‘Ultimately, we would like to understand which evolutionary drivers create a species with a life-history very similar to our ancestors.’
Location of photographs: Adelaide, South Australia and Paris Zoo, France
Photographer: Martina Nicolls
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