Learning penalty in nature

Source: NY Times

Science
Lots of Animals Learn, but Smarter Isn’t Better
By CARL ZIMMER
Published: May 6, 2008
New research indicates that growing smarter has dangerous side effects that make its evolution even more puzzling.

Really surprising research to me, though reading the article it makes sense that learning has its costs.

Here's a quote from the article:

Dr. Kawecki and like-minded scientists are trying to figure out why animals learn and why some have evolved to be better at learning than others. One reason for the difference, their research finds, is that being smart can be bad for an animal’s health.

And one more:

Dr. Kawecki says it is worth investigating whether humans also pay hidden costs for extreme learning. “We could speculate that some diseases are a byproduct of intelligence,” he said.

Hmmm...