Monkeys may be cute and cuddly in a zoo or in movies, but they are not well suited to living as pets. They need plenty of space to roam, eat, and play outdoors and cannot acclimate to life in a small house or cage. They also need special diets and medications. Moreover, the desire to own a monkey helps fuel the illicit wildlife trade and contributes to species extinctions and population decreases in the wild.
Monkeys typically live in groups, called troops, that range from a few individuals to thousands. They help each other find food, defend territory, and watch for predators. For these reasons, monkeys have evolved a variety of visual and auditory signals. One example is the emperor tamarin’s long, curled tongue signaling to its mate that it wants to offload its babies. Visual signals are not as effective in the dense forests and underbrush where most primates live, however, so they must also communicate with sound.
A rhesus macaque’s calls and facial expressions can convey many different emotions, including fear, aggression, and even yawning, Live Science reports. Researchers have also found that the vocalizations of some monkeys can resemble human speech. One study found that a marmoset could produce frequencies that correspond to the sounds of five vowels—A, E, I, O, and U.
Some monkeys, such as baboons, have warning cries that warn of danger. Others, such as putty-nosed monkeys, combine two call types into meaningful sequences. A study found that females travelled farther after hearing a playback of their males’ ‘pyow’ and ‘hack’ combinations than after listening to a series of random noises.