One of the siamang’s most distinctive features is its large gular, or throat, sac. This sac is found in both males and females, and can be inflated to be as large as the animal’s head. It serves as a resonating chamber for the siamang’s vocal cords, allowing it to make loud, resonating calls that can be heard over two miles away. These calls serve an important social function as a form of territorial defense, advertising that a particular location is already owned by a mated pair.
If there are a million apes and there are a million people, where is the million in between that to present us the theory of evolution?