Well, chalk one up for homo-sapiens, sort of. While we've known for some time that humans have been affecting the enviroment on a global scale, one aspect of our evolutionary impact on other species might not be all bad.

In a recent study, University of Minnesota biologist Emilie C. Snell-Rood found evidence suggesting that our direct changes to the natural habitats of animals (through technologies advances, antibiotics and revised food pyramids) have caused some animals to evolve with bigger brains.

Dr. Snell-Rood studied dozens of individual animal skulls, some as old as a century, from ten different species including bats, gophers and mice. In two of the species, the white-footed mouse and the meadow role, the brains of the animals plucked from metropolitan areas or suburbs were about 6% bigger than those of the animals taken from farms or other rural areas. Dr. Snell-Rood's hypothesis after assessing the first wave of results was that brains become significantly bigger when they move to cities or bustling towns, where the animals must learn to find food in places that they're not biologically trained to encounter or expect.

An increase in brain size was also detected in two species of shrews and bats, both found in rural Minnesota, which at first seems to conflict with Dr. Snell-Rood's theory about the impact of stimulating city environments and brain growth. This leads to her second proposition, which is that this increase occurred due to radical changes in the environment brought on by the people. As farms replaced forests, the disruption in the environment caused animals to evolve, and those who survived were better at adapting and more likely to breed.

Similarly, researchers at the Uppsala University in Sweden conducted experiments in which they bred guppies for larger brain sizes, and essentially proved that animals with bigger brains tend to learn tests quicker, meaning they generally learn better.

Jason Munshi-South, an evolutionary biologist at Fordham University calls the results "exciting and deserving of much follow-up work." Such secondary research may include the breeding of small-brained rural mammals with big-brained mammals, in an effort to collect information on the genes involved in producing different brain sizes.

So, at least there is one upside to humans' impact on the environment.