6 of the Most Sensitive Noses in Nature

If real animals could talk like Toucan Sam, the fictional cereal mascot, they’d likely repeat his iconic catchphrase “follow your nose!” Many creatures rely on their highly sensitive noses more than their eyes and ears to find food, detect predators, or navigate their surroundings. Some critters are even able to perceive odors from miles and miles away. Let’s take a closer look at six of the most sensitive schnozzes you’ll find in the animal kingdom.

African Elephants

The African elephant is arguably the most sensitive sniffer in the animal kingdom, as it has the keenest sense of smell of any mammal studied to date. A 2014 study determined that African bush elephants have roughly 2,000 olfactory receptor genes — components in a creature’s genetic makeup responsible for their sense of smell. To put the number in perspective, that’s roughly 67% more olfactory receptor genes than in rats, 150% higher than many dogs, and roughly five times more than the average human.

One of the most impressive ways in which elephants use their sense of smell is to detect water. In fact, they can smell water from up to 12 miles away. Furthermore, not only can elephants use their noses to detect food sources, but they’re also able to detect quantities of food through smell alone, ensuring they know where to find the most sustenance.

Bloodhounds

Bloodhounds are so trusted for their sense of smell that they were the first animal whose evidence was made legally admissible in U.S. courts. These talented pooches possess a staggering 230-300 million olfactory cells (the sensory neurons that transmit chemical signals to the brain) in their nasal cavity — about 40 times more than humans. 

Furthermore, bloodhounds have an olfactory center in their brain that’s about the size of a handkerchief, which is critical for processing those chemical signals triggered by smell. In humans, that same olfactory center is the size of a postage stamp. Last but not least, bloodhounds use their loose facial skin and long ears to trap and keep odors closer to their face, allowing them to hold onto and follow scents over long distances.

Catfish

While they may lack a protruding nose or snout like you’d find in many land vertebrates, catfish are still among the most capable sniffers. When it comes to detecting odor, these aquatic creatures rely on two openings in the front of their face called nares, which they use explicitly for smelling and not breathing. Beyond those holes is the olfactory rosette, which are tissues that detect smell arranged in a rose-like pattern (hence their name). A catfish has 140 folds within the rosette — more than any other freshwater fish — and the more folds there are, the greater the surface area to detect and process smells.

Catfish use their strong sense of smell to perceive potential danger, find their way home, detect other fish, and track down food. They can even detect certain smells at as little as 0.00017 parts per million. To put this in perspective, that means they can detect a single teaspoon of an odor within a pond that’s one-acre in surface area and three-feet deep.

Whitetail Deer

Whitetail deer have an incredible acuity to pick up scents from over a half mile away. It’s due, in part, to the 290 million or so olfactory cells present in an average whitetail deer’s nasal cavity. These deer also boast olfactory centers in their brains that are roughly four times larger than the same type of odor-processing centers in humans.

Another element that makes whitetail deer such keen smellers is a concept called “stereo olfaction.” It has to do with a deer’s nostrils, which are situated in such a way that a deer can detect whether the smell is coming from the left or right. It allows deer to determine where danger may be lurking, and avoid it accordingly. Whitetail deer also have a separate organ capable of detecting scents in addition to their nose, and it’s known as the vomeronasal organ. This organ is located in the roof of the mouth, and can pick up nearby pheromones with ease.

Cows

Anyone who’s ever passed a cow farm may plug their nose, considering the strong odors emanating from those piles of cow dung all over the place. But cows don’t seem to mind the smell, despite the fact they have a far keener sense of smell than humans. Cows have an estimated 1,071 olfactory receptor genes, give or take, which is roughly 2.5 times greater than humans.

Cows are able to easily detect and process a wide variety of scents. They can determine whether something is rancid, floral, hay-like, spicy, spearmint… the list goes on and on. They’re even known to detect those odors from up to six miles away. In addition to their noses, cows also have a vomeronasal organ in the roof of their mouths they use to detect odors, specifically scents related to reproductivity. To do this they perform what’s called the flehmen response, where they curl back their upper lip, bare their front teeth, inhale for several seconds, and suck pheromones towards the vomeronasal organ.

Sharks

You can’t publish an article about sensitive noses without mentioning these mighty aquatic beasts. Sharks are quite adept when it comes to detecting odors, as two-thirds of their brain weight is dedicated to detecting smells. A shark’s nares are also completely disconnected from their respiratory system, and are used solely for smelling, which allows them to detect scents with greater precision. Sharks use this ability to track down potential predators, prey, mates, and to navigate low-light environments.

It’s widely known that sharks are attracted to blood, but it may surprise you to learn that sharks can detect one single drop of blood in one million molecules of water using scents alone. To put that into perspective, it’s like if you were walking for 16 straight miles, and could pinpoint a specific inch on the way. Or being able to pick out a precise minute over the course of two years.