A bark is an animal vocalization defined by its acoustic properties: a short, abrupt burst of noise that is relatively loud and high-pitched. This sound often includes a rapid change in frequency and is commonly repeated in quick succession, creating a familiar staccato pattern. This specific acoustic structure serves as an effective signal across diverse forms of life. The production of this sound is a widespread behavior seen across numerous, unrelated mammalian and avian groups, not just the animals most people associate with the noise.
The Canid Vocalization
The domestic dog is the most familiar example of an animal that barks, but its frequent vocalizations are an outcome of its domestication. Wild canids, such as wolves, coyotes, and jackals, use the sound much less often in nature. In these wild relatives, barking is constrained, typically reserved for immediate alarm or as a territorial warning. For instance, the bark makes up only about 2.4% of a wolf’s total vocal repertoire.
The difference in vocal frequency is often attributed to neoteny, the retention of juvenile traits into adulthood. Since wolf pups bark more often than adults, the domestic dog’s frequent barking is thought to be a continuation of this youthful behavior. Domestication introduced wider contexts for barking, such as attracting attention or expressing excitement. The Australian dingo, a wild dog, barks sparingly, using a short, monosyllabic sound almost exclusively for warnings.
Non-Canine Animals That Bark
The term “bark” describes the distinctive vocalizations of many mammals beyond the canine family. The Muntjac deer, native to South Asia, is known as the “barking deer.” When disturbed, Muntjacs emit a loud, repetitive alarm call that closely resembles a dog’s bark, sometimes continuing for an hour or more to warn other deer.
In the marine environment, eared seals like fur seals and sea lions produce loud, repetitive barks. This vocalization is prominent in rookeries, where males use it to assert dominance and establish territory during breeding. Many primate species, including baboons and various monkeys, also use a bark-like sound for warning or as an aggressive display during disputes.
Among smaller mammals, rodents like prairie dogs and chinchillas make vocalizations described as barks. Prairie dogs use barks and chirps to signal the presence and type of predators, demonstrating a sophisticated alarm function. Even some birds, such as parrots and owls, produce bark-like sounds for territorial defense or when startled.
Why Animals Use Barking
The widespread presence of barking across unrelated species suggests this vocalization serves a deep biological purpose. The most common function is alarm signaling, a short-range warning that alerts nearby conspecifics to an immediate threat. The abrupt, loud nature of the sound is highly effective at drawing attention to the source of danger.
Barking is also associated with mobbing, a cooperative anti-predator response. When an animal detects an intruder, the initial bark signals the group to join in a vocal display that may intimidate the threat. Motivationally, the bark often signals an internal conflict, representing tension between the instinct to flee and the urge to defend territory or offspring.