The mental skills of some birds such as parrots may match those of apes, including their capability of thinking logically, of recognising themselves in the mirror and of empathy, a new study has claimed.
At first glance, the brains of birds and mammals show many significant differences. For the study, researchers compiled studies which showed diverse cognitive skills in birds.
"The mental abilities of corvids and parrots are as sophisticated and diverse as those of apes," said Onur Gunturkun from Ruhr University Bochum in Germany.
Among other things, they are capable of thinking logically, of recognising themselves in the mirror and of empathy, researchers said.
In mammals, cognitive skills are controlled by the multi-layered cerebral cortex, also called neocortex.
This brain structure does not exist in birds; instead, complex mental tasks are managed by the so-called pallium. Moreover, birds have much smaller brains than apes.
To address the question of how birds are capable of the same cognitive performance as apes, researchers analysed numerous neuro-anatomic studies.
They found that on the whole, the brains of both animal groups have indeed very different structures. When examining them in detail, however, similarities have become apparent.
Single modules of the brains, for example, are wired in a similar way, and both animal groups have a prefrontal brain structure that controls similar executive functions.
It is not known how these similarities have evolved. Either their last common ancestor passed the neuronal basis to birds and mammals. Or more likely, they evolved independently of each other, because both animal groups faced the same challenges, researchers said.
According to them, this would mean that certain wiring patterns in the brain are necessary to boost cognitive performance.
"What is clear is that the multi-layered mammalian cortex is not required for complex cognition," said Gunturkun.
"The absolute brain weight is not relevant for mental abilities, either," he said.
While ape brains weigh 275 to 500 grammes on average, birds, who are just as skilfull despite lacking a cortex, only manage 5 to 20 grammes, researchers said.
The findings were published in the journal Trends in Cognitive Sciences.
