Tortoises are slow to react to most external stimuli, which makes us wonder just how developed their senses are, especially their ability to smell. However, don’t let their inertia fool you, as they’re capable of smelling far better than you may think.
Tortoises can smell substances in the air, such as chemicals and pheromones, due to the vomeronasal organ at the roof of their mouth. This isn’t part of their nasal chambers, so it’s unknown how far tortoises can smell airborne odors. However, they can smell food on land and in water.
A tortoise’s sense of smell is a crucial part of how it navigates the world around it. Also, tortoises need to be able to use their sense of smell to stay mentally stimulated.
How Well Can a Tortoise Smell?
Tortoises have a good sense of smell, especially when perceiving chemicals and pheromones.
However, their chemoreceptor abilities are different from their normal olfactory system, so it can be hard to tell the true nature of their sense of smell. With that said, there’s no doubt that it’s among their strongest senses.
Tortoises can smell certain things better than humans because of a patch of cells on the roof of their mouth called Jacobson’s organ, also known as the vomeronasal organ. Jacobson’s organ is a chemoreception organ connected to the nose and the mouth.
Chemoreceptors are cells used by animals to process chemical stimuli. It helps the animal mix its sense of taste and smell to process the information.
You may notice that a tortoise opens its mouth slightly as it’s tasting the odor particles in the air so that the particles come in contact with its Jacobson’s organ.
However, Jacobson’s organ primarily helps tortoises smell moisture-based odors, chemicals, and hormones, not airborne odors. Airborne odors are perceived by a different part of the tortoise’s olfactory system—the part located in their nasal chambers.
Studies on how well tortoises can smell can be confusing because of these two separate olfactory systems.
Thanks to various studies—like this one published in American Zoologist—we know that tortoises can learn a lot about other tortoises due to their highly developed ability to smell pheromones. However, it’s still debated how well they can pick up scents using the olfactory cells in their nasal chambers.
Can Tortoises Smell Each Other?
The best way for tortoises to get to know each other is through smell. According to Copeia, tortoises smell each other to learn things such as:
- Sexual maturity
- Tell different tortoise species apart
However, only male tortoises can tell the sex and sexual maturity of another tortoise because male tortoises are the ones who pursue the females when it’s time to mate.
To ensure they aren’t spending energy trying to mate with a tortoise that isn’t female or too young, male tortoises are equipped with a powerful olfactory system.
Unlike some other animals, tortoises don’t use smell to exchange pleasantries. They use their sense of smell to gain valuable information, but not as a form of bonding or social interaction.
Tortoises are solitary creatures and don’t live in groups. Mother tortoises will even leave her young a few days after laying her eggs.
So, the ability to gather so much information about each other through smell is only to avoid cross-breeding with other species and for males to find viable females to mate with.
Can Tortoises Smell Food?
Tortoises have no problem smelling their food. They’re natural foragers that need to be able to find their food from a great distance.
Tortoises are slow and need to preserve their energy. If they didn’t have their amazing sense of smell, they would have to travel long distances to find something to eat. Instead, they can smell edible substances from afar, so they can go straight to them.
When you place food near your tortoise, it‘ll be able to smell it. Tortoises are all different, so they have different responses to smelling food.
Some may go to it immediately, others wait before eating, and many seemingly don’t react, but only because they were already expecting the food.
If your tortoise doesn’t want to eat what you put in front of it, it could be due to:
- Not liking the food
Tortoises are opportunistic eaters. In the wild, they don’t have an abundance of food, so they’re usually enthusiastic about anything you put in front of them.
It’s normal for them to decline certain foods sometimes since they have preferences, but not eating isn’t normal. Tortoises can smell the food you lay out for them, so if they don’t react to it, you need to monitor your tortoise for signs of illness.
Can Tortoises Smell Water?
Tortoises can smell water, especially if it has been contaminated.
No studies have been done to showcase if they can smell completely fresh and clean water. However, water that has been contaminated gives off a certain smell that tortoises are more than capable of detecting.
The water sources wild tortoises encounter aren’t clean by our standards. They contain plants, fish, and microorganisms. Given the fact that tortoises eat fish, it’s safe to assume that they can smell the fish and catch them.
The water doesn’t hinder their ability to smell their food.
Can Tortoises Smell People?
Tortoises can smell people and can recognize their owners by scent. Tortoises are known to have excellent long-term memories.
The Okinawa Institute of Science and Technology proved that tortoises could remember things they learned years ago.
Long-term memory is important for forager animals. Being able to remember where food can be found is a skill that ensures an animal’s survival.
So, not only is your tortoise able to recognize who you are because of your smell, but it will also remember your odor for a long time.
How Far Can a Tortoise Smell?
How far a tortoise can smell isn’t clearly defined.
Some experts say that they can only smell from a few feet away, while others argue that they can smell things from over 30 feet away. The reason nobody can decide is that the two kinds of olfaction tortoises are capable of are often confused.
It is theorized that tortoises have long-range olfaction and short-range olfaction. When foraging for food or looking for a mate, they use their long-range olfaction, in which they use the cells in their nasal chambers.
When close enough, they use their Jacobson’s organ to smell the chemicals or hormones coming from their target.
The best way to know how far your own tortoise can smell is to test it out. When you let your tortoise explore, you can hide or place food farther away until you think your tortoise can’t smell it anymore. In fact, it’s recommended that you do this to play with your tortoise.
What Senses Do Tortoises Have?
Tortoises have the same five senses as humans.
It may not seem like it because they don’t have the same body parts we do, but they’re sensitive to external stimuli.
Most tortoise species have tastebuds and prefer some foods over others. Their shells contain a lot of nerve endings that allow them to feel when they’re being touched, and they have great hearing and eyesight.
What Is a Tortoise’s Strongest Sense?
A tortoise’s strongest sense is a tie between their sense of touch and smell. Those two are their most developed senses because the other senses have certain weaknesses, at least in comparison to humans.
For example, tortoises have good hearing, but they can only perceive lower frequencies. They have great eyesight but have relatively poor depth perception. They have tastebuds, but experts note that they don’t have that many and cannot distinguish between foods with subtle tastes.
Their sense of touch and smell seem to be the most well-rounded senses.