Contenuti
Multimediali
Since their first appearance in the Cambrian period, brains have undergone deep evolutionary changes — diverging into many forms and sizes depending on the environments different species lived in.
A human brain weighs about 1.3 kg and contains around 86 billion neurons.
The brain of the nematode Caenorhabditis elegans is far smaller — around 180 neurons.
An African elephant’s brain weighs about 6 kg with roughly 257 billion neurons.
Some animals even change their brain size seasonally: the coal tit — a small bird — increases the volume of its hippocampus by about 30% in autumn, shrinking back again in spring.
This diversity reflects equally diverse cognitive abilities and behaviours — but not in a simple, linear way. Brain weight, size, and neuron count alone don’t explain everything.
The investigation becomes more complex — and richer in clues.