Hearing unusual sounds in the darkness can be unsettling, especially when they resemble a low, guttural grunt or snort. Many nocturnal wildlife species use these specific vocalizations as a primary form of communication. These sounds are not random but serve distinct purposes in an animal’s life cycle. Understanding the nature of these noises is the first step in identifying the creature responsible for the nighttime disturbance outside your window, and this guide will help narrow down the potential culprits.
Common Mammalian Grunters
Raccoons are frequently responsible for nocturnal sounds, often making a chuffing or purring grunt when feeding or communicating with their young. When these animals are confronted or engaged in a fight over territory or food, these sounds can escalate quickly into loud, persistent growls and aggressive snorts. Raccoons are highly adaptable and are commonly found in residential areas, often exploring trash cans and decks.
White-Tailed Deer bucks produce deep, low nocturnal grunts, particularly during the autumn breeding season, known as the rut. These vocalizations are often repeated and serve as a display of dominance, establishing a hierarchy among competing males. The sound is highly resonant and can carry a significant distance in the quiet night air.
Wild Hogs and Boar produce snuffling, rooting, and aggressive grunts as they forage for food in the soil. These sounds are often accompanied by the distinct noise of them digging into the earth with their snouts, known as rooting. These vocalizations are particularly common where populations are dense, and they are almost always heard close to the ground as the animals move slowly.
Lesser-Known Sources of Grunts
Certain large amphibian species, such as the American Bullfrog, produce a deep, low bellow that can sometimes be mistaken for a grunt. These calls are usually heard near permanent bodies of water, such as ponds or slow-moving streams. They are most prevalent during the warm, humid nights of late spring and summer. The sound’s consistent location near a water source is a strong indicator of its amphibian origin.
The defensive snort or sharp hiss of a startled skunk can often be confused with a small, sharp grunt when heard from a distance. This sound is a clear, rapid, forceful expulsion of air that acts as an immediate warning before the animal sprays its defensive musk. This noise is almost always a reaction to a perceived threat rather than a form of general communication or foraging sound.
Behavioral Reasons for Grunting
Grunts are utilized as territorial signals or to attract a mate, particularly among male mammals like deer and boar. These specific vocalizations, often referred to as rut calls, establish a hierarchy among competing males. The sound is generally rhythmic and highly repetitive, designed to advertise the animal’s presence and vigor to both competitors and potential mates.
Many nocturnal foragers use grunts and snuffles while rooting in the soil, especially those that root in the soil, such as wild pigs or raccoons. These sounds are a byproduct of the physical action of pushing the snout through dirt and leaves to locate food. When multiple animals are feeding together, these competitive feeding grunts can intensify due to the close proximity and the need to defend a discovered resource.
A sudden, sharp grunt acts as an indication of distress or preparation for a defensive action. This sound is often emitted when an animal is startled by a predator or a human, or when two animals are engaged in a skirmish over territory. Unlike mating calls, defensive grunts are usually singular, explosive noises designed to startle a threat and buy the animal time to escape.
Practical Tips for Identification
Determining the time the sound occurs and its location is the first step in identifying the source of the noise. Sounds originating high up or near rooflines might suggest an arboreal animal like a raccoon. Noises consistently heard at ground level point toward terrestrial species. The time of night is also telling, as some animals are most active right after dusk, while others forage closer to dawn.
The sound’s quality—its pitch, repetition, and duration—can narrow the possibilities. A low, sustained, repetitive grunt suggests a territorial or mating call, whereas a sharp, singular snort points to a sudden defensive reaction. Volume is also a factor, as a loud sound suggests a larger animal is close by.
Looking for physical evidence the next morning provides confirmation of the animal’s identity. Look for signs such as disturbed vegetation, hoof prints, or the characteristic rooting damage left by a wild boar. Finding scat or hair samples near the location of the noise can also help definitively identify the nocturnal visitor.