Echolocating night-hunting aerial interceptors

The book Evolutionary Wars contains a section bearing the title above. In layman's terms, it describes the method by which bats hunt insects at night. Author Levy writes, The most difficult task for nocturnal airborne predators is to detect, locate, intercept and successfully engage a moving target.  To achieve success, the predator must acquire an almost continuous stream of information giving instantaneous data about the target's size, velocity, direction and altitude. (pg. 188) The complexity of the work involved for mere survival of the bat is astounding.  Flying is only one complex function. By its description echolocating is several -- essentially using its "naturally" occurring sonar capability to navigate and hunt without being able to physically "see" it's prey. As part of a lengthy technical description of how bats eat insects, Levy says, If the echo returns at a lower pitch, the target is moving away; if the echo is at a higher pitch, the target is approaching. Each ear picks up the echo at a slightly different intensity and time.  In this way, the bat's minuscule on board computer, it's 10 milligram brain automatically triangulates and gives in-flight directions for the intercept. Charles Levy implies a slight in his opinion of this remarkable creature when he  describes the bat's brain by weight.  Admittedly, only ten milligrams for a brain is only a tiny fraction of the weight of the brain an average human carries around in their head, is around three pounds. On the other hand, I've learned there are some birds that seem to be a bit smarter … [Read more...]