A Rat's Sense of Smell

Well, practically there's just almost no end to the amazing things rats posses when you talk about it. Even its olfactory senses are a thing of beauty when you come to think of it and we're going to talk about it now in this article.

You may have already asked from reading on a previous article, the question of "how do rats exactly see the things around them?" and you may also have already a vague idea how things work for them when sensing their environment. While it is true that they mainly base their perception on their sense of touch, the role of their sense of smell also happens to be a very crucial one. In fact, the sense of touch in rats may not even be made possible without their sense of smell. In other words, they will become partly blind without their noses. If a person, with an impaired would see things blurrily, a rat may also experience the same relative situation in perceiving their surroundings. So how does a rat's nose exactly work? This is perhaps one of the main questions that we will answer first in this article when we are to understand the nature of rats' sense of smell fully.

The Function of their Noses

When the air passes through the nostrils of a rat, it reaches a point where it flows on a patch of skin, mostly comprised of highly sensitive smell receptors. These receptors are called olfactory epithelium. This is where olfactory neurons are hurdled up in a big bunch to provide the rats a keener sense of smell. The neurons have tip of hair-like cilia, which projects itself from a bath of mucus around the cell exterior. Odor molecules or particles that are whiffed along with the air bind themselves into the specialized receptors of rats and receptors will then quickly serve as a trigger for a consequential brain response. Odor particles are actually called odorants.

Amazingly, there are actually about 500 to 1000 kinds of odor or olfactory receptors in rats. These are then encoded to 500 to 1000 genes. Come to think of it, this is already a very staggering amount of olfactory receptors to one creature. Their sensory receptors virtually comprise 1% of the total rat DNA. That would simply mean, that in every 100 genes, there's one gene that's allocated to the sensory reception of rats. This, gargantuan number of genes would only go to prove how crucially important the sense of smell is to rats.

Secondary Odor Detecting Organ

Besides a rat's nose, there is also another organ responsible for detecting scent from the surrounding. This organ is called the vomeronasal organ, abbreviated as VNO. This organ is normally situated in a pouch out of the nasal area. The VNO in rats are situated in their nasal cavity, inside a cigar shaped entrance located right next to their septum. The VNO has a narrow opening just right about within the rat's nostril. The dead end of this organ simply implies that air can't flow through it.

The organ actually mainly detects pheromones. Pheromones are more or less signals transmitted through a scent coming from a member of the same species. Therefore, the organ is used for a higher form of communication in rats. In rats, since urine secretion is a way of marking its territories, the scent of their urine signals the other rats to keep away from their turfs. And this is made possible through their vomeronasal organs. Unlike their main organ used for smelling, the VNO is only comprised of very few scent receptors. About 30-100 kinds of receptors are encoded and interpreted.