White-tailed deer have five sets of external glands: 1) preorbital glands in the corners of the eyes; 2) tarsal glands on the inner surfaces of the hind legs; 3) forehead glands located, as the name implies, on the forehead; 4) metatarsal glands on the outer surfaces of the hind legs; and 5) interdigital glands between the hooves.
Each gland secretes a different scent called a pheromone. The word pheromone [pronounced fair-a-moan] means a chemical substance that is produced by an animal and serves as a stimulus to other individuals of the same species for one or more behavioral responses.
These scents are part of a communication system that identifies individual animals.
Mechanisms for release of glandular secretions are not well understood by scientists. Both hormonal and sympathetic nervous stimulations may be involved.
In addition to the pheromones from the glands, deer use urine as a scent.
Fawns rub-urinate when they are frightened, and older deer do the same in aggressive situations.
During this behavior, the animals rub their hind legs together while urinating on the tarsal glands.
In white-tailed deer, the tarsal glands, interdigital glands and rub-urination serve the same functions. However, scientists have found the metatarsal scent does not produce an alarm reaction and whitetails seem to depend more strongly on behavioral clues, such as the raised tail, than on pheromones as alerts to danger. The preorbital glands are reduced in function to tear glands.