The Flehmen Response in Dogs: Does it Really Exist?
Disclaimer: this article is not meant to be used as a substitute for professional veterinary advice or behavioral advice. If your dog is acting sick or aggressive please consult with a qualified professional for proper diagnosis and treatment.
Use of the term "flehmen response in dogs" isn't very accurate considering the fact that dogs display a slightly different variant of the Flehmen response seen in other animals.
To gain a more comprehensive understanding of the differences, it helps to take a look at the formal definition of the Flehmen response in other animals, when it takes place, and how it manifests and then draw comparisons with the canine counterpart.
So let's discover more about the flehmen response in dogs and how it works.
What is the Flehmen Response?
The flehmen response consists of an animal behavior that is characterized by the curling back of the upper lip which causes the teeth to be exposed. This high-neck posture is maintained for several seconds.
A variety of animals exhibit the Flehmen response including felines and ungulates. Horses, cattle, deer, goats, and big cats like lions and tigers are known for flehmening.
What Triggers the Flehmen Response?
The flehmen response is triggered by an olfactory substance that captivates the animal's interest.
When animals curl their lip, they are basically transferring pheromones and other scents to their vomeronasal organ, through a specialized duct that is found just behind the animal's front teeth.
What is the vomeronasal organ? It's a special organ responsible for the detection of pheromone molecules. These nonvolatile chemical messages are deposited in the urine and other bodily secretions of animals.
Once the scent is transferred through the duct to the vomeronasal organ, the information reaches areas of the brain associated with emotions and reproductive behavior.
This information plays a crucial role in the animal's social interactions, mating behavior, and overall understanding of its surroundings.
Did you know? The vomeronasal organ is called this way because of its closeness to the vomer and nasal bones.
What are Pheromones?
The term pheromone derives from the Greek word "pherein' which means to transport and "horman" which means excitement.
The term is therefore utilized to depict substances that are secreted for the purpose of influencing the behavior of the animal who senses them.
For sake of comparison, the mechanism is similar to an answering service system. A person leaves a message on the answering machine that is then relayed to the receiver when he comes home and presses a button.
Animals though do not have an answering machine, instead they are equipped with special glands meant to emit pheromones and a special organ meant to pick up these messages (the vomeronasal organ).
How are Pheromones Released?
Animals can emit pheromones in a multitude of ways as they have several special glands built for this very purpose.
Among dogs, pheromones are commonly released when they urine mark. A dog's "pee-mail" is meant for the next dog to acknowledge that "Rover was here."
To help the pee-mail be noticed more readily, dogs will often aim their urine at vertical items so that they are conveniently located at "another dog's nose level," sort of like the human practice of placing a business card on a bulletin board at eye level in a busy shopping center.
These pheromones are then picked up by another dog, courtesy of their vomeronasal organ which is purposely built for detecting pheromones.
Did you know? Randall H. Sprague and Joseph J. Anisko in their study "Elimination Patterns in the Laboratory Beagle," were able to identify several different peeing postures assumed by dogs when eliminating.
Related: Discovering 12 Dog Peeing Positions
Do Dogs Exhibit a Flehmen Response?
No, dogs do not display the typical lip curling action that is typical in other animals. However, they do exhibit another behavior that appears to share several similarities in its exhibition and function.
Rather then curling the lip, dogs engage in a behavior that is known as "tonguing," where the dog’s tongue is pushed rapidly against the roof of the mouth, with the teeth sometimes chattering.
Sometimes dogs may also be drool and foam may collect on the dog's upper lip.
Tonguing behavior in dogs often takes place after the dog licks a urine spot or "tastes the air" following the exchange of threat displays between two rival males.
Did you know? According to board-certified veterinary behaviorist Dr. Betsy V. Beaver, dogs are most likely trying to exhibit a Flehmen response, but are prevented from doing so due to the dog's philtrum attaching the lips to the upper jaw.
What Dogs Engage in Teeth Chattering and Tonguing Behaviors?
In a study, data was collected in regards to what dogs engaged in teeth chattering behaviors.
During a short long-line walk, it was found that these behaviors were significantly more often in intact (not castrated) male dogs compared to neutered male dogs.
This proves that these behaviors are likely to be male-specific traits that are likely linked to reproduction.
In studies of wolves, there is evidence that the vomeronasal system carries out a sexual function. Wolves have been found to respond to methyl p-hydroxybenzoate (methyl paraben, MP), which is a sexual pheromone secreted in the urine of female dogs when ovulating and in standing heat (estrus).
The effect of methyl p-hydroxybenzoate is likely to impact domestic dogs as well. When a female dog is nearing the heat cycle, male dogs will sample the urine through the vomeronasal organ and this may help them determine at what point she is in the heat cycle. Experienced intact male dogs are particularly good at this.
Did you know? Methyl p-hydroxybenzoate is quite potent! In a study where the sexual organs of female domesticated dogs not in heat (anestrus) were topically treated with methyl p-hydroxybenzoate, male dogs started to exhibit mating behavior.
If Not a Flehmen Response Then What is it Called?
Since a dog's teeth chattering behavior is not a version of the classical "horse laugh-like" Flehmen response, what is it called?
There doesn't appear to be an official term, however, one particular study refers to a dog's the teeth chattering and salivation following the licking of urine, as "flehmen-like behaviors (FLB).
References:
Goodwin M, Gooding KM, Regnier F (1979) Sex pheromone in the dog. Science 203
Dunbar, I. 1977. Olfactory preferences in dogs: The response of male and female beagles to conspecific odors. Behavioral Biology
Berthoud, Daisy & Nevison, Charlotte & Waterhouse, J. & Hawkins, Dawn. (2013). The effect of castrating male dogs on their use of the vomeronasal organ when investigating conspecific urine deposits. Journal of Veterinary Behavior: Clinical Applications and Research
Pageat P., Gaultier E. Current research in canine and feline pheromones. Vet Clin North Am [Small Anim Pract]. 2003
Canine Behavior: Insights and Answers by Betsy V. Beaver
Lindsay, Steven R. (2000)Handbook of applied dog behavior and training. Vols 1 Iowa: USA
