Moles, often unseen beneath the earth’s surface, are commonly believed to be silent. Yet, they are not mute; they produce a variety of sounds for different purposes within their underground world. These vocalizations and physical noises are integral to their survival and interaction, though they remain mostly imperceptible to human ears.
The Range of Mole Sounds
Moles generate a diverse array of sounds, categorized into vocalizations and non-vocal noises. Vocalizations include squeaks, chirps, snorts, growls, and chattering sounds. Some species, like immature star-nosed moles, emit high cries, while adults may produce wheezing noises. Naked mole-rats, a highly vocal subterranean rodent, have an extensive repertoire that includes soft chirps, alarm calls, food recruitment calls, and specific vocalizations for their pups. Giant mole-rats possess an even richer vocal array, distinguishing at least 14 different vocalizations.
Beyond vocalizations, moles create non-vocal sounds primarily associated with their digging activities. These include scratching noises as they excavate soil, rustling sounds as they move through their tunnels, and the displacement of earth. Blind mole rats utilize vibrational signals, such as head drumming, to communicate through the ground. These physical noises, while subtle, complement their vocal expressions.
Purpose and Audibility of Mole Communications
Mole sounds serve various communicative functions within their underground habitat. Vocalizations are used for communication regarding food sources, territorial claims, and social status. Moles also employ sounds as warning signals to alert others of danger or to intimidate rival moles. During mating seasons, specific calls are used to attract potential partners. Mother moles may use grunts to signal to their pups that it is safe to emerge from the nest.
The audibility of these sounds to humans is generally limited. Moles primarily use low-frequency sounds because these propagate efficiently through soil, unlike higher frequencies which are quickly attenuated. While moles can perceive a wide range of frequencies, including some beyond human hearing, their auditory sensitivity is often poor, with hearing ranges typically between 0.1 and 15 kHz. This adaptation means most mole sounds are too low in volume or too specific in frequency for human ears to detect without specialized listening equipment. In rare instances, humans might hear a mole squeal or scream, particularly if the animal is distressed or handled.