Bats: Sonar equipment
Hunting success, however can mean momentary loss of it senses for if its mouth is filled by an insect, a bat cannot squeak in the normal way. Some species avoid this difficulty by squeaking through their noses and developed a variety of grotesque nasal outgrowths which serve to concentrate the beam of the squeak and act like miniature megaphones. The echoes are picked up by the ears and these too are elaborate, extremely sensitive and capable, in many cases, of being twisted to detect a signal. So the face of many bats is dominated by sonar equipment - elaborate translucent ears, ribbed with cartilage and laced with an intricate pattern of scarlet blood vessels; and on the nose, large protrusions to detect sounds. The combination and patterns of protrusions on the nose and ear structure is species specific so that each can produce a unique call. Receptorssynchronized to particular sounds filter out signals from other bat species. The system, described in such terms, sounds simple but when you encounter several million bats flying simultaneously in pitch darkness represented by eight species as occurs in the Gomanton Caves in Borneo you realize that echolocation has become a highly sophisticated sensory apparatus.