City Animals Have More Street Smarts

Scientists Find Urban Mammals Have Bigger Brains

by Sydnee Griffin, age 16


For years, humans have been changing animal habitats. New research suggests that we could also be changing the size of animal brains.

By chopping down trees, building more apartments and paving new roads, humans have been carving up the rural area these animals inhabit. This has resulted in naturally urban creatures having brains six percent larger than rural creatures.

University of Minnesota biologist Emilie C. Snell-Rood conducted an experiment involving century-old skulls from ten mammals housed in the University’s Bell Museum of Natural History. Undergrad Naomi Wick used the dimension of each skull to estimate the size of the animal’s brain. Her data show that the brains of the mammals in cities were larger than those of their counterparts in rural areas.

Dr. Snell-Rood believes this is a result of humans changing the landscapes. Forests and prairies yielded to cities, displacing these mammals, influencing survival capabilities of these animals. Lack of forests and other rural areas force animals to scavenge farther and farther away from their homes. This can be a dangerous and demanding task for small-brained animals.

Researchers also took note that larger-brained animals were not only more capable of learning, but were more likely to stay alive and reproduce.

Studies by other scientists support the connection between bigger brains and better learning. Researchers at the University of Sweden Uppsala performed an experiment using guppies bred for larger brains. Scientists found that the large-brained guppies scored higher on learning tests than the small-brained guppies.

Dr. Snell-Rood’s hypothesis on the larger animal brain is still quite new. Others in the field recognize that Snell-Rood’s ideas need to be tested in more ways to rule out other explanations for the change in brain size. If Snell-Rood’s idea is proven true, museum skull collections all over the world could serve as the constant variable in further research. With continued research, we might one day be able to more precisely measure human influence on animal intelligence.

[Source: The New York Times]

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