"We didn't expect these spots to be so sensitive because the animals are so heavily armored," co-author Duncan Leitch said in a press release. Leitch, a graduate student, performed the studies under the supervision of Ken Catania, a professor of biological sciences at Vanderbilt University.

The technical name for the spots is "integumentary sensor organs" or ISOs. Scientists over the years have speculated that they held all kinds of functions, from secreting oil to detecting electrical fields. A study in 2002, however, suggested that they detected ripples made by water, so that led to the latest research.

"This intriguing finding inspired us to look further," Catania said. "For a variety of reasons, including the way that the spots are distributed around their body, we thought that the ISOs might be more than water ripple sensors."