Washington: Researchers have found that echolocation works better than eyesight, even under adequate light.
The new study showed for the first time that bats catch insects by sonar as it is far more efficient than using vision, even during twilight.
Bats have eyes and may not have evolved their ultrasonic sonar from the earliest time of their existence on earth. Approximately 1000 species of bats use sonar to detect prey, despite showing considerable variation in the preferred size of their prey and their mode of hunting.
Arjan Boonman and colleagues from Tel Aviv University here model the quality of information that two species of bats receive from sonar and eyesight when hunting for insects.
The researchers found that both species use their sonar as much in twilight (1 to 10 lux) as in complete darkness. They show that this reliance on ultrasonic sonar is advantageous, because sonar detects insects at distances that are 0.25 to 5 m shorter than eyesight, even under low- and intermediate light intensities.
By making it possible to catch small prey more efficiently than with vision only, sonar has opened a unique niche for bats and promoted their astounding diversification.
The study is published in Frontiers in Physiology.