The tarsal gland secretions of each individual are slightly different from those of other members of the group and so serve as a form of identification. Fawns use these pheromones to identify their mothers among the female deer in the herd. A fawn may sniff the tarsal glands of a number of females before finding the correct one.
Pheromone Communication is Complex
But as scientists have continued to look into the chemical language of animals, they have found that, in many species, some pheromones are made up of not just one or two, but many chemical compounds that are precisely blended and balanced. Each component contributes to the overall meaning of the message. Some beaver pheromones, for example, may contain as many as 50 different substances.
The proportions of these chemicals in the pheromone mixture vary somewhat from beaver to beaver, almost like a chemical signature. Futhermore, researchers now know that pheromone communication is more complex in some kinds of animals than in others. In the insect world, for example, pheromones generally trigger very predictable, almost automatic responses.
Pheromone Responses Vary
To complicate matters even more, environmental factors can make things complicated. Factors such as temperature, humidity, light intensity, and the time of day or year also affect how pheromone messages are sent and interpreted in a wide variety of animal species.