These are usually linked to sexual attraction and they elicit an immediate response. This response is usually rapid. 

Releaser Pheromones

These can influence menstrual cycles, puberty, and other factors of development or reproduction. These can also alter the hormone levels of the individual who receives the pheromones. These take a longer time for a response. 

Primer Pheromones

These provide information and can help a mother recognize her newborn through scent. 

Signaler Pheromones

These are usually found in sweat and can alter bodily functions. These can also affect a female's menstrual cycle. 

Modulator Pheromones

1. Releaser
2. Primer
3. Signaler
4. Modulator

University of California, Davis

Pheromones are specialized chemical messages secreted by an individual to communicate with other members of the same species. This type of communication is often utilized to broadcast a potential mate's reproductive status.

Pheromones

MediLexicon International. (n.d.). Pheromones: Function, in humans, types, and news. Medical News Today. https://www.medicalnewstoday.com/articles/232635#_noHeaderPrefixedContent. 

What are pheromones and do humans have them? 

It has been observed in male rodents that the vomeronasal organ, which contains receptor sensory cells, detects pheromones from females. This sends axons to the olfactory bulb in the brain. These neurons launch to the medial amygdala, which circulates testosterone to maintain a masculine function during copulation. This sends axons to the mPOA, which merges all of this information to lead to ejaculation. 

Male Copulatory Circuitry in Rodents

One specific instance where pheromones are seen to communicate between individuals of the same sex is in elephants. During the elephant's mating season, males emit a liquid pheromone behind their eyes that has a distinctive smell. This certain pheromone displays a lower rank, which helps them avoid superior "mature-smelling" males, and therefore avoid fights. 

Communication between individuals of the same sex

This is a highly specialized system that detects pheromones and sends the information to the brain. This system is found in most terrestrial mammals. 

Vomeronasal system

These are receptors produced in the olfactory epithelium, and are possible pheromone receptors.

Trace amine-associated receptors (TAARs) 

Pheromones Reference Library

Pheromones are not a regular hormone, they are considered ectohormones because they are secreted outside of the body and they influence another individual's behavior. 

Ectohormone

Types of Pheromones

In certain species like rats, pheromonal signals play a critical role in mating behaviors. For instance, a female rat prepared to reproduce will release pheromones to draw the attention of nearby males. This pheromonal activation is an important factor in triggering sexual behavior in the male rat.

Pheromonal Communication in Rats

While pheromonal communication is well-documented in many animals, the role and existence of pheromones in humans remain a subject of significant scientific research and ongoing controversy.

Research and Controversy on Human Pheromones

Analyze the following scenario and identify the specific type of chemical communication being used. Justify your answer by explaining how the elements of the scenario fit the definition of this communication type.

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