Wildlife SOS introduces a new series “Things You Didn’t Know About” that explores fascinating and lesser-known facts about various species. Our writers will spotlight one aspect of the wild, unveiling its unique characteristics and role in the ecosystem. Did you know that some animals can release chemicals as messages for their species? In this feature, we look at the organ that can unravel information hidden in these chemicals — the Jacobson’s organ.
We now know about the five primary senses of animals: sight, hearing, taste, touch, and smell. What is not commonly known to many are the several extraordinary abilities of certain wild species such as echolocation, magnetic field detection, and the power to identify chemicals in their surroundings. Researchers have found out that many animals use what is known as a Jacobson’s organ to sense traces of chemicals that are found in their environment.
Named after Ludvig Levin Jacobson, the anatomist who discovered the organ in 1811, Jacobson’s organ comprises a sensitive set of nerve cells that can analyse chemicals present in the scent captured by animals. This is why the organ is recognised as a chemosensory organ — it can detect chemicals called pheromones that are produced and secreted by members of the same species, by their prey and even by their predators. These pheromones also carry messages that can help another from the same species identify a potential mate or possible danger.
Reptiles, amphibians, and some mammals possess Jacobson’s organ, which is also known as the vomeronasal organ as it is a strong partner of the olfactory system. For reptiles, the Jacobson’s organ is located on the roof of the mouth, to which the tongue transfers the scent collected. For amphibians and mammals, this stimulating organ is located in the nasal cavity.
Let’s understand how Jacobson’s organ is used by the following animals that belong to three different groups:
Reptiles: Snakes
Snakes possess forked tongues that are highly responsible for their basic survival. As a compensation for poor eyesight, the tongue becomes the reptile’s guide that can inform it on how to navigate its surroundings. If you’re wondering how a tongue can do that, take a second to think of the last snake video you watched. You may recall that the snake’s tongue slides out of its mouth and flicks around, before it is taken back in. This is when the tongue is collecting information to pass on to its Jacobson’s organ! This organ can indicate their prey’s location and its trail. Not only does the organ help the snake to satiate its appetite, it can also identify potential mates for the reptile. The airborne pheromones secreted by the opposite sex of the same snake species are picked up by the forked tongue, which rolls back in to contact the Jacobson’s organ on the roof of the mouth — thus communicating the message.
Mammals: Elephants
Like many mammals, elephants communicate through pheromones that are released through various bodily fluids such as sweat, urine, secretions from their temporal glands, and even dung. To interpret the subtle yet vital messages that are left within pheromones, elephants require a supreme decoder — the Jacobson’s organ! When a bull elephant encounters a patch of urine left by a female, he will often lift his trunk and blow the scent into the roof of his mouth. This behaviour in elephants is known as the Flehmen response, a reaction that mammals like horses, zebras and leopards display rather differently. Having picked up chemicals with the tip of the trunk, the bull elephant curls it back into the mouth where the Jacobson’s organ is. This organ scans information left in the pheromones that indicate the female’s readiness to mate. This fascinating process highlights the intricate ways in which elephants communicate and interact.
Amphibians: Frogs
Amphibian species like frogs lead life both above and below water. Interestingly, some specific species of toads possess two noses to suit both aquatic and terrestrial environments. Most frogs have a nasal cavity with three chambers and a big-sized Jacobson’s organ. When under water, the Jacobson’s organ can actively assess the matter that is found around them.
Frogs also rely on the Jacobson’s organ for communication in the context of mating and territory marking. Male frogs can use this specialised sensory structure to decipher pheromones released by female frogs during the breeding season, guiding them toward suitable partners.
The Jacobson’s organ, with its amazing sensitivity to pheromones, grants an extraordinary advantage to animals that need assistance with their existing set of senses in their environments. The remarkable organ helps animals possessing it expand their awareness of their habitat and the life that exists in it, opening up paths to survival. To read more interesting articles on wildlife, subscribe to our newsletter here.
