Humans are more rational than other living creatures. But, it has been proved that most of the other animals too possess a certain cognitive ability.
However, we cannot always agree with the concept of bigger body, bigger brain, because it’s a fact that the brain doesn’t expand as the body gets bigger.
Hence, the evolution of the animal kind has remained a mystery so far. To solve this puzzle, a group of researchers has done an experiment on the brain size and the cognitive ability of 1, 400 species living and extinct. What they wanted was to find a pattern in growth in body size along with IQ of these species.
” At first sight, the importance of taking the evolutionary trajectory of body size into account may seem unimportant,” the evolutionary biologist Jeroen Smaer who works in the Stony Brook University stated.
“After all, many of the big-brained mammals such as elephants, dolphins, and great apes also have a high brain-to-body size. But this is not always the case.”
Breaking this pattern, the mental capacity of the California sea lion has been found as equal to a chimpanzee. This doesn’t make the sea lions stupid or primary. Sea lions are known to be fast learners and easily adapt cognitively with human interaction. These animals have 3.6 times better volume in their autonomic and sensory functions.
Polar bears who are smaller in size own the brains which are two times bigger than the sea lions’.
” We’ve overturned a long-standing dogma that relative brain size can be equivocated with intelligence,” Kamran Safi, a biologist and a research scientist at the Max Planck Institute of Animal Behaviour further explained.
“Sometimes, relatively big brains can be the end result of a gradual decrease in body size to suit a new habitat or way of moving – in other words, nothing to do with intelligence at all.”
The research on body and brain size of the species led the group to have some insights of the historical changes.
For example, in Cretaceous, tiny mammals such as bats, rats shrews got their brain capacity bigger along with their body size.
“A big surprise was that much of the variation in relative brain size of mammals that live today can be explained by changes that their ancestral lineages underwent following these cataclysmic events,” Smears explained.
However, it’s difficult to find a pattern in the body size and the cognitive ability of the animals which proves that bigger doesn’t mean brighter.