Marmots are large, ground-dwelling squirrels famous for loud vocalizations that cut through the high-altitude air of their mountain habitats. The question of whether these sounds are truly “screams” earned them the nickname “whistle pig.” While the sounds are often described as whistles or chirps, the intensity of a marmot’s most urgent call can resemble a human scream. This powerful auditory signal serves as a highly effective, long-distance warning system for the entire colony.
The Signature Sound: Alarm Whistles and Screams
The most recognized marmot vocalization is the alarm call, a high-pitched sound classified as a whistle or chirp. For example, the Yellow-bellied Marmot’s common alarm sound is a brief, single-note whistle lasting about 50 milliseconds. These short vocalizations are repeated rapidly, creating piercing bursts that communicate immediate danger. The pace of the chirps quickens into a “trill” when the animal is frightened or the threat is close.
In extremely high-risk situations, such as a direct chase by a predator, marmots may emit a distinct and rare “fear scream.” These screams are produced in moments of acute distress. The alarm call’s primary function is to signal the presence of a predator, such as a coyote, fox, or eagle, to the colony. While some species vary their calls based on the predator type, the Yellow-bellied Marmot primarily uses the rate of the whistle to communicate the degree of risk or urgency.
Beyond the Whistle: Other Marmot Vocalizations
Marmot communication extends beyond the loud alarm whistle, including a range of sounds for social interactions. These less intense vocalizations are shorter, lower in frequency, or softer in volume. One such sound is the “chuck,” a low-frequency, quiet vocalization emitted after a threat has passed as the animal settles down. Chucks are difficult to record due to their subdued nature, often only inferred when a marmot opens its mouth and shakes its body.
Other social sounds include growls, used in dominance encounters or territorial defense, and tooth-chattering, which serves as a direct threat display. Marmots also use specific, quieter calls for communication between a mother and her young, facilitating social bonding and coordination. These softer sounds allow for close-range communication without broadcasting their location to potential predators. The varied vocalizations show that the marmot’s auditory repertoire is complex, serving many social functions beyond signaling danger.
Why the Call Matters: Social Ecology and Survival
The marmot alarm call is central to its social ecology, functioning as an altruistic behavior that benefits the entire colony, often at a cost to the caller. Marmots that call at higher rates are more likely to die, suggesting the vocalization draws the predator’s attention. This risk is mitigated by the benefit to the caller’s closely related kin. Individuals often serve as “sentinels,” scanning the surroundings from a safe vantage point and initiating the call upon spotting a threat. The sound immediately prompts the rest of the colony to become alert, scan their surroundings, and retreat into their burrows.
The ability to vary the call rate allows the colony to coordinate its response to the level of danger. A faster rate of chirps signals a high-risk situation, such as an immediate chase, demanding a rapid retreat underground. Conversely, a slower rate may indicate a lower-risk situation, prompting increased vigilance without an immediate dive. This warning system ensures the survival of the group and demonstrates kin selection, where the individual risk of calling is outweighed by the collective benefit to relatives.