When a pheromones reviews hormone is produced within the body, it must initiate a process or it also acts like the triggering factor that can initiate the response for some essential process. Some most important pheromones, which act inside the body, are releaser, signal, and primer. These pheromones play an important role in the development and initiation of the developmental process in the body. Signal pheromone is responsible for short tasks. When there is a need of producing neurotransmitter for some time, the signal pheromone helps to produce the neurotransmitter. Another most important pheromone is a primer. Primer can initiate any changes in the body of recipient. Other pheromones are territorial pheromones and trail pheromones. The territorial pheromone is very interesting and useful. It is used to mark the territory among animals. Cats and dogs mark their territory by depositing the territorial hormones in their fecal matter, which is usually deposited on the grounds. A territorial animal mark the boundary for its place or nest.