A mammalian display is a set of distinct behaviors that functions as a form of communication. These actions are often predictable and repeated among individuals of the same species, forming a vocabulary of signals. The information conveyed through these behaviors influences social relationships, reproductive success, and survival.
Agonistic Behavior and Social Hierarchy
Agonistic behavior refers to social behaviors associated with conflict, including threats, aggression, and appeasement. The primary function of these displays is to settle disputes and assert social standing while minimizing the risk of serious injury from direct combat. Through these ritualized interactions, mammals establish and maintain a social order.
A dominant wolf communicates its status with a stiff-legged posture, raised tail, and direct stare, often accompanied by bared teeth and flattened ears. In contrast, a submissive wolf will make itself appear smaller by lowering its body, tucking its tail, and averting its gaze. This exchange reinforces the pack’s hierarchy without a physical fight, with one animal yielding to the other.
Other mammals use displays to signal strength and deter rivals. A silverback gorilla performs a chest-beating sequence to signal his power and position as the group’s leader. Similarly, male deer engage in ritualized contests where they lock antlers and push one another. This is a test of strength, with the weaker individual retreating to prevent severe injuries.
Courtship and Reproductive Displays
During the breeding season, mammals use courtship displays to attract mates and signal their readiness to reproduce. These behaviors often function as honest signals of an individual’s health, genetic quality, and fitness. A more elaborate or vigorous display suggests a stronger, healthier individual, making them a more attractive choice for passing on genes.
Auditory signals are a common feature of courtship. Humpback whales produce complex songs that last for hours and can be heard by other whales miles away, which is believed to play a part in mate attraction. On a smaller scale, male deer produce loud calls during the rut to attract females and ward off competing males.
Visual displays also play a role in mammalian courtship. The male mandrill develops bright coloration on his face and rump, a display of red and blue linked to his social status and hormone levels. This advertises his dominance and reproductive fitness to females. Many mammals also rely on chemical signals, releasing pheromones that communicate sexual receptivity.
Territorial and Alarm Signals
Mammals use displays to communicate information about their environment, from marking territory to warning others of danger. These signals are for securing resources and ensuring group safety. Territorial displays often involve long-lasting signals that communicate an individual’s or group’s presence even when they are not physically there.
Chemical communication is a common method used to mark and defend a territory. Many species use scent marking by depositing urine, feces, or secretions from specialized glands. Bears rub their backs against trees to leave their scent, while large cats like leopards spray urine along their domain boundaries. Beavers construct and mark mounds of mud and vegetation with a musky secretion called castoreum.
Displays are also used to alert social group members to a predator. These alarm signals can be auditory or visual. The white-tailed deer, when fleeing, raises its tail to expose a white underside, a visual alarm for other deer. Prairie dogs use sharp, barking calls to communicate the type and location of a threat, allowing the colony to take cover. A beaver slaps its tail on the water’s surface, creating a loud sound that warns others of danger.