People tend to associate intelligence with brain size. And as a
general guideline, this makes sense: more brain cells, more mental
capabilities. Humans, and many of the other animals we’ve come to
think of as unusually bright, such as chimpanzees and dolphins, all
have large brains. And it’s long been assumed that the smallest
brains simply don’t have the capacity to support complex mental
processes. But what if they do?
The vast majority of Earth’s animal species are rather small, and a
vanishingly small portion of them have been studied at all, much less
by cognition researchers. But the profile of one group of diminutive
animals is rapidly rising as scientists discover surprisingly
sophisticated behaviors among them.
“There is this general idea that probably spiders are too small,
that you need some kind of a critical mass of brain tissue to be
able to perform complex behaviors,” says arachnologist and
evolutionary biologist Dimitar Dimitrov of the University Museum of
Bergen in Norway. “But I think spiders are one case where this
general idea is challenged. Some small things are actually capable
of doing very complex stuff.”