According to a new study, small animals with brains that are relatively large compared to their body size are better suited for survival. Eric Abelson, a biologist at California’s Stanford University, analyzed the brain size and body weight of a number of species to determine the correlation between the two factors. He that plotted body size against brain size, and discovered that most species follow a predictable curve: larger brain size correlates with larger body size. However, those animals outside the curve, which had a brain size larger than that predicted by the model, were more likely to resist extinction. The limitation of this curve is that it only applies to smaller species, that is, those weighing in at 10 kg or below. When an animal gets larger, the bigger body outweighs the benefit of a bigger brain. Larger animals require more food, space, and other resources, and they usually only raise a few offspring late in life. Scientists think that this new discovery has implications for changing climate: the larger-brained little guys will likely outlive a changing environment, whereas those with smaller brains will not. However, brain size doesn’t necessarily correlate with ingenuity in humans. First of all, we don’t follow “Abelson’s rule” due to our size. Human males weigh an average of approximately 80 kg (176 lbs); females weigh approximately 60 kg (132 lbs). Furthermore, recent research has shown that our brains are actually shrinking. John Hawks from the University of Wisconsin says that the average human brain has lost 150 cubic centimeters over the course of the last 20,000 years. But that doesn’t mean we’re getting dumber. Some scientists think that the brain could be losing volume because our neural pathways are becoming more and more efficient. If that still doesn’t quell your fears about being “small-brained,” here’s food for thought: Einstein’s brain weighed at least 200 grams less than the average brain of a human male from his time!
Read the original article in Nature online news.
Read more about our shrinking brains at DiscoverMagazine.com.