CHICAGO, Sept. 5 (Xinhua) -- A University of Michigan (UM) study shows that when bipedal desert rodents called jerboas are being chased, sudden changes in direction, gait and speed help them elude hungry predators.
A UM team led by Talia Moore, a postdoctoral research fellow at the UM Department of Ecology and Evolutionary Biology, found that the jerboa's superior evasiveness arises from its unique gait use.
Although bipedalism has evolved multiple times in different types of rodents including kangaroo rats and Australian hopping mice, jerboas are the only group observed to use three different footfall patterns or gaits when moving on their long hind legs: hopping, skipping and running.
Though previous study suggested that jerboas hop at the lowest speeds, skip at intermediate speeds and run at the highest speeds, Moore's team found no significant difference between the mean speed of each gait.
Through a set of laboratory experiments, Moore and her colleagues found that jerboas move with step-by-step changes in gait, which cause frequent changes in stride length, direction and speed. Their evasive maneuvers can include momentary bursts of acceleration, kangaroo-like hopping, erratic zigzagging and acrobatic leaps.
These herky-jerky movements help jerboas foil an aerial predator's efforts to calculate an intercept course, Moore and her colleagues suspected.
The findings may help engineers make biomimetic robots that are tailored to specific environments. The results also suggest that bipedalism in desert rodents may have evolved to limit interspecies competition and to increase animal diversity.
The study was published in Nature Communications on Tuesday.
