Xiaomin Paredes, a professor at George Mason University, and Jennifer E. Mapes, a professor at the University of Michigan, who first described these patterns in the journal Science in 2010. The work was funded by the National Institutes of Health and the National Center for Ecologic Research at Virginia Tech.

“There are so many variables at play, it is not possible to give an answer to what is causing the patterns, but these are likely to influence the distribution of species,” Mapes said.

Some patterns, such as the distance from water and time of day when species move over water, are very obvious. But others may also signal a complex interplay between time and locations on a lake. For example, species moving into the sunnier parts of Lake Superior will likely be in higher elevations and greater sunlight. Or, if a species’ food sources are very scarce, it may migrate to areas in which it has enough food, such as an island in a river, Mapes said. These and other factors influence the distance, and even the timing, which species move, she noted.

Although researchers cannot pinpoint how much of a factor influences a species’ movements, “they can certainly take notice of the patterns that are there and look for explanations for their persistence.”