Commentary: Echolocation and vision complement each other in two bat species

Citation: Melcón ML (2015) Commentary: Echolocation and vision complement each other in two bat species. A commentary on It's not black or white—on the range of vision and echolocation in echolocating bats Many nocturnal mammals have developed senses such as vision, olfaction, and whisking to orient, navigate and forage in dark environments. Most bats, however, have evolved developing echolocation—an active sense that works as a sonar system. While it is clear the advantages that echolocation possess in complete darkness, it is not well understood why bats count on echolocation and nocturnal vision to operate at light levels as encountered at dusk. In the research article " It's not black or white–on the range of vision and echolocation in echolocating bats, " Boonman and colleagues were able to shed light into the probable use of two complementary sensory systems used by echolocating bats. For this, they used both a theoretical as well as an empirical approach to compare the performance of vision and echolocation in two bat species whose peak activity takes place immediately after sunset—i.e., intermediate light levels. Both methods used in the manuscript conveyed similar conclusions: vision performed better at detecting large objects such as trees, whereas echolocation worked better in the detection of small objects, disregarding light levels (Boonman et al., 2013). By using Rhinopoma microphyllum and Pipistrellus kuhlii, Boonman et al. (2013) ensured to include two bat species with very different echolocation signals that exploit two different habitats: R. microphyllum is an open space aerial hawker which hunts on large insects, and P. kuhlii is an edge space aerial hawker which specializes in catching small insects. Authors found for both experimental models that echolocation is superior for navigation under extreme darkness and for detecting and tracking small objects, such as insects. For example, they estimated for P. kuhlii an acoustic detection range for a mosquito of 2–4 m, and visual detection range of 0.5–1 m, depending on the method used. Similarly, R. microphyllum's detection range was estimated at 2–5.5 m with echolocation, while only 0.5–1.5 m with vision. What are the advantages of echolocation over vision? Echolocation happens to work better for continuous tracking of objects since it is independent on the contrast. It also provides animals with a more accurate estimation of distance to the target, speed, and distance to the background. So why not just use echolocation? Vision has its advantages as well, such as …