The groundhog (Marmota monax), also known as the woodchuck, is a substantial rodent recognized for its extensive burrowing habits in North America. Despite their seemingly solitary lifestyle, these mammals possess a varied repertoire of sounds used for communication and defense. These vocalizations range from soft, close-contact sounds to a loud alarm signal, which is the sound most commonly associated with the species.
The Distinctive Alarm Call
The most recognizable groundhog sound is a high-pitched, sharp whistle, which earned the animal the alternate name “whistle-pig.” This loud, shrill call is exclusively an alarm or warning signal, typically emitted when the groundhog perceives a threat, such as a fox, coyote, or human observer. The sound is a sudden chirp that alerts other groundhogs in the vicinity to danger.
This penetrating whistle can reportedly be heard up to 500 yards away, making it an effective means of communication across expansive territories. When a groundhog spots a predator, it often stands erect on its hind feet to survey the area before whistling. The immediacy of the whistle prompts nearby individuals to retreat quickly into their burrows for safety. It serves as a rapid defense mechanism.
Other Vocalizations for Close-Contact
Beyond the alarm whistle, groundhogs produce lower-frequency sounds reserved for close-range social interaction or defense when cornered. One common non-vocal sound is teeth chattering, an aggressive display used to signal agitation or warn an opponent to retreat. This sound warns that the animal is prepared to defend itself using its large incisors.
When a groundhog is fighting or feels trapped, it may emit deep growls and hisses, indicating heightened aggression and a readiness to engage physically. These growls often precede a physical skirmish with a territorial rival or a predator. Softer sounds, such as low barks, squeals, and murmurs, are also part of their communication; squeals signal distress or confrontation, while softer sounds are associated with young kits or mating interactions. These non-whistle sounds are rarely heard by humans unless they are in close proximity to the animal, often near a burrow entrance.
When and Where to Hear Groundhogs
Groundhog vocalizations are most likely to be heard during their active period, from early spring when they emerge from hibernation until they retreat in the fall. They are diurnal animals, active during the day, with peak vocal activity often occurring around dawn and dusk while foraging outside their burrows. Their movement increases the chances of encountering a predator, making the alarm whistle more frequent.
Alarm whistles are typically heard in open areas where groundhogs are feeding or near burrow entrances, as the sound needs to travel long distances to warn others. Conversely, the growls, hisses, and chattering are restricted to the immediate vicinity of a conflict, often near or inside the burrow where the animal is defending its territory or young.