Moles are small, subterranean mammals that spend most of their lives underground, leading many people to assume they are silent creatures. This perception is understandable, as direct observation is rare, and their environment is not conducive to sound transmission. Despite this, moles produce a variety of noises, both vocal and mechanical, that serve important functions. Understanding these sounds provides insight into their social behaviors and daily existence.
Vocalizations Used for Communication
Moles are capable of a range of true vocalizations, which are primarily used for short-range communication in their underground tunnels. These sounds are often high-pitched and include distinct squeaks, chirps, and chattering noises. The chattering is sometimes described as a series of rapid, low-volume sounds exchanged during close contact.
These vocalizations are context-dependent, serving specific biological needs such as territorial defense or courtship. During the breeding season, which typically occurs from late winter into spring, male moles may emit high-pitched squeals as they tunnel in search of a mate. This signaling helps them locate one another in the complex tunnel networks.
Aggressive encounters, such as territorial disputes between males, can produce louder sounds like guttural snorts or sharp squeals. When a mole is startled or captured, it may emit a distress call, which is often a loud, sharp screech that serves as an alarm signal. Mother moles also use soft grunts to communicate with their pups in the nest.
Non-Vocal Sounds of Tunneling
The sounds most commonly associated with moles are the non-vocal noises of their daily activities. These mechanical sounds are a direct result of their powerful digging action, using their large, spade-like forepaws. The primary sound of a mole at work is the scraping and displacement of soil.
As the mole pushes through the earth, the claws scratch against soil particles, rocks, and plant roots, creating a rustling or rasping noise. The movement of loose dirt being pushed aside to form new tunnels or molehills creates a distinct sound of shifting earth. This noise is highly localized and can sometimes be heard faintly on the surface near an active tunnel or fresh mound.
These constant tunneling sounds provide a sonic map of activity. For other moles, the subtle vibrations and sounds of soil being worked can serve as a warning of another mole’s presence or a general indication of a territory’s boundaries.
Factors Limiting Sound Detection
The reason these vocal and non-vocal sounds are so infrequently heard by humans relates directly to the physical properties of their subterranean habitat. Soil acts as an efficient sound dampener, significantly reducing the intensity and carrying distance of any noise. Sound waves traveling through dense earth lose energy quickly compared to those traveling through air.
Mole vocalizations are naturally low in volume, designed for close-contact communication over short distances within the confines of a tunnel. The physical structure of the tunnels, with their curves and branches, also increases sound attenuation, meaning the noise fades out rapidly over a short distance.
Most mole vocal activity is restricted to short, specific periods, such as the mating season or brief, aggressive encounters. This limited window for sound production, combined with the dampening effects of the soil, means that a person must be in very close proximity to an active mole at a precise moment to hear anything beyond the faintest scratching.