How do animals use scent to communicate?

Many animals use chemical communication or pheromones to communicate. They may leave their scent to mark territory or attract mates. They often use smell to find prey and identify other animals. Animals often use chemical communication to mark territory. They leave pheromones, or chemical marks behind. Some animals leave scent posts to mark their territory. Scent posts set the boundaries of an animal's territory. The male mountain lion often kicks up piles of pine needles, dirt or leaves with its hind feet and urinates on the pile to mark its territory. The Canada lynx also leaves a scent post, it will urinate on trees and tree trunks. Snakes use their forked tongues to collect pheromones of prey animals that are in the air. Some animals use scent to identify members of their family. Domestic cats have scent glands near their mouths, on their foreheads and at the base of their tails, they use these glands to mark territory.

Dogs use both sight and smell to assess their surroundings and communicate. They have more than 100 million sensory receptor sites in the nasal cavity compared to 6 million in people, and the area of the canine brain devoted to analyzing odors is about 40 times larger than the comparable part of the human brain. With a single sniff, noses interpret an entire story without words by using amines and acids emitted by dogs as the basis for chemical communication. The chemical aromas communicate what a dog likes to eat and identify gender and mood. By simply smelling, a dog can determine if a new friend is male or female, happy or aggressive, healthy or ill. Dogs get a general idea about each other with a quick sniff, but get more detailed information by getting up close and personal, which is why some dogs sniff private parts of the anatomy. Changes in odors may convey where the dog went, what he ate, and what he did. When in a new territory, a dog can sniff a tree and determine what other dogs live in the neighborhood. Dogs also sense fear and anxiety via their noses. When we are stressed or scared, we secrete adrenaline, the fight-or-flight hormone, which dogs detect even though we cannot smell it. Jacobsen’s organ communicates with the part of the brain that deals with mating, by identifying pheromones, it provides male and female dogs with the information they need to determine if a member of the opposite sex is available for breeding.

Animals may use scents to proclaim their readiness to mate, to mark out territorial boundaries, to warn off intruders and predators or, in some cases, to attract prey. The most basic substance for these purposes is strong smelling urine, but there are other and more refined methods of producing lingering odours. These take the form of scent glands which may be situated in the hooves, on the face or close to the anus or scrotum. Bees, wasps, ants, moths and other insects rely largely upon pheromones as a means of communication. Pheromones are chemical substances which may be secreted in urine, dung or produced by special glands. They are usually given off by the female of the species to attract males. Dung is another readily available source of scent used by many animals to mark their territory, with some species accumulating and regularly adding to large heaps of droppings which act as territorial marker posts. Male hippos will mark their with their dung by using their tail as a kind of muck-spreader. Snakes have the most unusual means of detecting scents, they use their tongue to pick up scent particles in the air. Having flicked out its tongue the snake then returns it to a special organ in the roof of the mouth which analyses the scents collected.