Dogs are known to deposit their pheromones, which is there in their urine on explicit landmarks to spot the border of the required territory. This explains how pheromones work. Territorial pheromones help him define this territory. Also the ants secrete the trail pheromones which helps them move in the highly disciplined form. It also helps them to return back at their home once they have collected the food and guide other ants as well.
Alarm pheromone sends special signals to the members belonging to the same species. It is done when an organism is attacked or he is about to have a fight with his enemy. In fact plants also release pheromones, when attacked. The surrounding plants in such case release these chemicals and make the food which the enemy cannot eat properly.
On the other hand sex pheromones initiate the sexual desires in animals. They helps in many ways starting from getting the signals whether there is any presence of the partner for mating purpose and finding the possible mate. There are certain pheromones which can even communicate different information about their species and the hereditary constitution. On the other hand aggregation pheromones is a chemical substance that is released by the both the sexes of the particular species so as to attract the individuals of both the sexes. Bees and many other animals are also present who are still being researched to know do pheromones work in their case also.
The most special of all of them are the human pheromones which enhance the libido and prove as to why pheromones work with such specialty. There are so many companies that even sell human pheromones that are supposed to acquire aphrodisiac properties. The amount of studies existing on human pheromones is nevertheless very limited.