What Gives Parrots Exceptional Cognitive Abilities And Long Life Spans? Study Gives Answers

Parrot intelligence: Researchers examined 217 parrot species, and found that species such as the scarlet macaw and sulphur-crested cockatoo have extremely long average lifespans, of up to 30 years.

New Delhi: Parrots are known to have remarkable cognitive abilities and exceptionally long life spans. According to a new study led by researchers at Max Planck Society, headquartered in Germany, one of the traits has likely been caused by the other. 

The study, titled 'Coevolution of relative brain size and life expectancy in parrots', was recently published in the journal, Proceedings of the Royal Society B: Biological Sciences.

The researchers examined 217 parrot species, and found that species such as the scarlet macaw and sulphur-crested cockatoo have extremely long average life spans, of up to 30 years. Such exceptionally long life spans are usually seen only in large birds. 

The researchers explained that a large relative brain size could be responsible for such long life spans. The study is the first to show a link between brain size and life span in parrots, and suggests that increased cognitive ability may have helped parrots to evade threats in their environments and enjoy longer lives.

Also, parrots have life spans and relative brain size on par with primates.

Despite the fact that parrots are famous for their long lives and complex cognition, scientists have remained in the dark about whether the two traits influence each other, until now. 

Why Have Scientists Remained In The Dark Before?

Simeon Smeele, the lead author on the study, said the problem has been "sourcing good quality data", according to a statement issued by Max Planck Society. In order to conduct the study, the researchers compared living parrots.

Smeele said that comparative life-history studies require large sample sizes to provide certainty. 

How Did The Researchers Collect Data Of 217 Species?

Researchers from Max Planck Institute of Animal Behaviour and Max Planck Institute for Evolutionary Anthropology teamed up with Species360, an international non-profit organisation which maintains an online database of wild animals under human care. The scientists did so in order to generate an adequate sample size. 

The researchers compiled data from more than 1,30,000 individual parrots sourced from over 1,000 zoos. Due to the database, the researchers were able to obtain the first reliable estimates of the average life span of 217 parrot species, which represent over half of all known species.

According to the study, there was a surprising diversity in life expectancy, ranging from an average of two years for the fig parrot up to an average of 30 years for the scarlet macaw. The sulphur-crested cockatoo from Australia also had a long life span. It lives on an average 25 years. 

Smeele said that living an average of 30 years is extremely rare in birds of this size. She explained that some individuals have a maximum lifespan of over 80 years, which is a respectable age even for humans, and that these values are really spectacular if one considers the fact that a human male weighs about 100 times more than a parrot.

How Do Cognitive Abilities In Parrots Influence Their Longevity?

After this, the researchers used large-scale comparative analysis to determine whether or not parrots' renowned cognitive abilities had any influence on their longevity. 

According to the study, the researchers examined two hypotheses. The first hypothesis was that having relatively larger brains enable longer life spans. This means that smarter birds can better solve problems in the wild, thus enjoying longer lives. The second hypothesis was that relatively larger brains take longer to grow, and therefore, require longer life spans. 

The scientists collected data on relative brain size, average body weight, and developmental variables for each species.

Then, the researchers combined the data and ran models for each hypothesis. The study marks the first time a link has been shown between increased brain size and longer life spans in parrots. 

Since brain size relative to body size can be an indicator for intelligence, the findings suggest that the parrots with relatively large brains had cognitive capabilities that allowed them to solve problems in the wild that could otherwise kill them. This intelligence enabled them to live longer lives, the study said.

Smeele said this supports the idea that in general, larger brains make species more flexible and allow them to live longer. She gave the example of parrots running out of their favourite food, and eventually learning to find something new and survive. 

The study explained that factors such as diet or the greater developmental time required to develop larger brains did not result in longer average life spans, but the fact that intelligence helped the creatures evade threats and solve problems caused them to live longer. Smeele said they would have expected the developmental path to play a more important role because in primates, it is this developmental cost that explains the link between brain size and longevity. 

Did Sociality And Cultural Learning In Parrots Contribute To Long Life Spans?

The researchers also aim to explore whether sociality and cultural learning in parrots might have contributed to long life spans. Smeele said that large-brained birds might spend more time socially learning foraging techniques that have been around for multiple generations. This increased learning period could potentially also explain the longer life spans. This is because this increased learning period takes more time but also makes the foraging repertoire more adaptive.

The researchers are "excited" to see if long-lived parrots also have a 'childhood' in which they have to learn everything from finding and opening nuts to avoid upsetting the dominant male.