.......There is very much an "arms race" between echolocating predators and their prey. Many animals that are the prey of echolocating organisms have evolved defenses against them. At least six orders of insects are known to have evolved ultrasound sensitivity. The types of signals these insects detect influence their response. Some moths fly away when detecting a low amplitude ultrasound. This is a cue there is a bat in the distance and that the area should be vacated. A high amplitude sound, however, is a cue that a bat is likely nearby. The moth will initiate unpredictable power dives in order evade the predator.

.......Some moths are more active in their defense. There are certain species of tiger moths that can release ultrasonic calls after receiving those of bats. The purpose of these calls from the moths range from signaling its distastefulness, startling the bat, to even disrupting the predator's echo processing.

.......In more recent times, scientists have discovered that certain fish are sensitive to ultrasound. Cod may be able to detect echolocating predators at 10-30 meters. Shad are even more impressive, as they can detect the calls of a dolphin at ranges of 180 meters. Similar to moths, blueback herring swim away from ultrasonic calls. Some fish, such as clupeids, even exhibit evasive movement when receiving ultrasound signals [1].