Deer, which belong to the Cervidae family, navigate their world not just by sight and sound, but heavily through an intricate system of chemical communication. Olfactory signals are a primary way these animals convey information about their identity, social standing, and reproductive status. This reliance on scent is especially important because deer often inhabit dense cover where visual and vocal communication is limited. The body of a deer is equipped with several specialized skin glands that produce these chemical messages, which are deposited onto the environment or directly onto other deer.
The Tarsal Gland: Location and Anatomy
The tarsal gland is a specialized patch of skin found on the inside of each hind leg, specifically located at the hock joint, or tarsus. This area is easily identified by a tuft of stiff, elongated hairs that often appear discolored or stained. Beneath this tuft of hair are numerous sebaceous glands.
These sebaceous glands secrete an oily, fatty substance called a lipid that coats the specialized hairs. The hairs themselves are structurally modified with scales, which increases the surface area available for holding this oily material. This sebaceous secretion is largely odorless on its own, but its true function is to act as a scent wick. The skin also contains small muscles that allow the deer to flare the tuft of hairs, releasing a burst of scent when needed.
Presence and Function in Female Deer
Female deer, or does, absolutely possess tarsal glands, as do males and even fawns. Research indicates that the sebaceous glands associated with the tarsal tuft are active year-round in both sexes. Does engage in the behavior of “rub-urination,” where they allow urine to flow over the tarsal glands, though they do so less frequently than mature bucks.
The tarsal gland functions as a deer’s unique signature, allowing for individual identification within the social group. For a doe, this scent is particularly important for maternal bonding. Does likely use the odors from the fawn’s tarsal glands to confirm its identity, and day-old fawns have been observed rub-urinating.
While the glands themselves are active in both sexes, the resulting odor is less pungent in females compared to rutting males. This difference is due to the frequency of rub-urination and the presence of bacteria. The warm, moist, nutrient-rich environment of the gland allows for the growth of a diverse population of bacteria. These microbes interact with compounds in the urine to create the characteristic odor, which serves as a form of non-rut social signaling for the doe.
Tarsal Glands in Deer Social Communication
The tarsal gland scent is a highly effective form of identification, allowing deer to communicate information without direct contact. By sniffing the tarsal gland of another deer, they can determine the animal’s sex, age, health condition, and social status. This sniffing behavior is particularly common at night when reduced visibility makes visual identification difficult.
Differences in the scent’s chemical profile and usage clearly distinguish the sexes. The potent, musky odor associated with a rutting buck comes from the frequent rub-urination during the breeding season, which darkens the tarsal hairs and increases bacterial activity. The bacterial species richness is statistically higher on the tarsal glands of males compared to females, contributing to a more complex scent profile.
The tarsal gland acts as a chemical billboard, with the bacteria transforming urinary compounds into socially significant odors. The resulting volatile compounds can reflect an animal’s dominance and reproductive status, especially in males. The tarsal gland is considered the most significant for personal recognition and conveying complex social information within the herd.