In all animals, including humans, mental capacity varies markedly between individuals. It’s about making good decisions all the time, when it comes to choosing places to sleep, finding places with plenty of food, avoiding predators, and caring for the offspring. Some are simply better at avoiding the pitfalls of the struggle for existence.
In the current study, published in Science Advances, German researchers led by evolutionary biologist Claudia Fichtel studied the gray mouse lemur (Microcebus murinus) in western Madagascar.
Mouse lemurs are very small nocturnal monkeys. The gray mouse lemur, which weighs only 60 grams, lives on insects, fruits, flowers and nectar.
Fichtel and her colleagues captured 198 people who all took four intelligence tests and two personality tests.
Intelligence tests measured how well the lemurs are problem-solvers by seeing how quickly they learned how to open a cage of food, how well they remembered hidden pieces of food, how quickly they discovered shortcuts, and how quickly they figured out how to get treats by pulling on a string. In all cases, they were seduced by pieces of banana – something of a favorite food.
The personality tests gave an idea of how interested the animals were in investigating various things, and how curious they were about unknown things.
It was found that individuals who were curious and exploratory weighed more than other individuals, possibly as a result of being better at finding food.
These individuals also lived longer. Gray mouse lemurs live about 5 years in the wild, but the lemurs that had the best test results lived several months longer than other species with worse test results.
The results indicate that higher mental capacity leads to a long life. Generally. Mouse lemurs have many enemies and even the most intelligent individuals may be unlucky in life. But on average, being smart seems to pay off.
Lemurs (Lemuroidea) are a superfamily among proboscis monkeys that began evolving 55 million years ago. It is found only in Madagascar off the eastern coast of Africa.
The researchers draw on 108 species divided into five families: mouse lemurs, true lemurs, weasels, indris and fingerlings.
The largest species is indrine (Indri indri) with a weight of 6-10 kilograms. The smallest is the Perth mouse lemur (Microcdebus berthae) with a weight of 30 grams, which gives it the title of the smallest primate in the world.
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