Snakes are fascinating creatures that have evolved over millions of years to survive in a variety of environments. One of the most interesting aspects about snakes is their sensory abilities. In particular, many people wonder – do snakes have a sense of smell?
The Snake’s Olfactory System
The simple answer is yes, snakes do have a well-developed sense of smell thanks to their olfactory system. A snake’s olfactory system consists of two small nasal cavities located on the roof of their mouth. Each nasal cavity contains two main olfactory epithelium patches containing olfactory receptor neurons. These neurons detect chemicals in the air, activating the olfactory bulb region in the snake’s brain.
Snakes use their forked tongues to collect odor molecules and bring them to the nasal cavities. As the tongue flicks in and out, it gathers chemical particles from the air or ground and transfers them to two small openings in the roof of the mouth, allowing the snake to detect and analyze smells.
How Snakes Use Smell
A snake’s sense of smell helps it survive and thrive in the following ways:
- Hunting prey – snakes rely heavily on smell to locate potential prey like rodents, birds, eggs, and more.
- Identifying predators – snakes can detect the scent of predators like large birds, wild cats, and other snakes to avoid danger.
- Finding mates – male snakes identify receptive females during breeding season by picking up on pheromones.
- Locating habitat – snakes use smell to find secure nesting sites, sources of food, water, and more.
- Social communication – some evidence suggests garter snakes may release odor cues related to social status and communication.
Overall, smell provides snakes with crucial information about their environment and supports key survival behaviors.
Snake Smell vs. Human Smell
Compared to humans, a snake’s sense of smell is quite different and potentially much stronger. Here’s how snake smell compares to human smell:
| Snake Smell | Human Smell |
|---|---|
| Primarily depends on the olfactory system and tongue rather than nostrils/inhaling. | Depends on inhaling air through the nose into nasal cavity. |
| Main sensory neurons are in the mouth/oral cavity. | Main sensory neurons are in the nasal cavity. |
| May have up to 10 times more olfactory neurons overall. | Have around 10-20 million olfactory neurons. |
| Can detect some chemicals at levels as low as parts per billion. | Can detect some chemicals at levels as low as parts per million. |
| Use smell to track prey from a distance. | Use smell more to detect things in close proximity. |
This shows snakes have an olfactory system that is highly adapted for sensing smells relevant to their niche as carnivorous hunters.
Smell Ability Between Snake Species
While most snakes rely heavily on smell, there are some differences in olfactory capabilities across species:
- Rattlesnakes – Rattlesnakes like the western diamondback have a strong sense of smell adapted for chasing down rodent prey across long distances.
- Pythons – Pythons are constrictors that use smell to locate potential prey sources and select ambush sites when hunting.
- Vipers – Vipers often rely on smell to find their preferred prey of small mammals, lizards, and nesting birds.
- Garter snakes – Garter snakes have good general smell abilities, but they also use pheromones heavily for mating communication.
- Sea snakes – Sea snakes dwelling in aquatic habitats tend to have a weaker sense of smell not as critical to their survival.
So while most land snakes have strong smell capabilities, sea snakes and snakes feeding on fish may rely less on olfaction.
Scent-Tracking Behaviors in Snakes
Snakes exhibit some fascinating scent-tracking behaviors and movements related to their use of smell:
- Tongue flicking – snakes constantly sample the air using quick tongue flicks to collect odor molecules.
- Body alignment – snakes will align their body in the direction of an interesting scent trail.
- Head waving – snakes will slowly wave their head from side to side to help triangulate the location of a smell.
- Zig-zag trailing – snakes will follow a prey scent trail in a zig-zag pattern to pinpoint the source.
- Flehmen response – some snakes display a flehmen response of gaping open while exposed to strong scents.
Being attentive to these behaviors can help reveal when a snake is actively using its sense of smell.
Scent Reception in Snakes vs. Lizards
Snakes and lizards are both reptiles, but they have key differences in how they receive scents:
| Snake Scent Reception | Lizard Scent Reception |
|---|---|
| Mainly use tongue to collect odors. | Mostly rely on nasal passages and inhaling air. |
| Transfer odor molecules to roof of mouth. | Detect odors directly inside nasal cavity. |
| Have two small nasal openings. | Usually have two large external nostrils. |
| Flick tongue frequently to sample environment. | Do not flick tongue to sense smells. |
| Follow scent trails using tongue flicking. | Less likely to directly trail scents. |
So while lizards do have a sense of smell, snakes are much more specialized for actively tracking odors using their tongue.
Can Snakes Smell Through Their Skin?
Sometimes people wonder if snakes can smell through their skin like they “taste” the air with their tongue. However, there is no evidence that snakes can directly detect smells through their skin. The main smell receptors are in a snake’s nasal passages accessed using their tongue.
Some key reasons snakes likely cannot smell through their skin include:
- Lack of olfactory neurons in the skin – their smell neurons are concentrated in the nasal cavities.
- Skin is covered in scales – this limits exposure to odor molecules from direct contact.
- Need tongue delivery – the tongue brings scents directly to nasal openings.
- Lack of Flehmen response from skin contact – snakes don’t display this scent response from skin exposure.
So while their skin may pick up some scents from contact, snakes cannot actively “smell” things just by touching them with their body.
Conclusion
In summary, snakes do have an excellent sense of smell that aids their survival in many ways. Their specialized olfactory system and tongue allow them to track prey, find mates, detect predators, and learn about their environment using chemical cues. Smell provides vital sensory information to snakes as they carry out key behaviors.
While not all snake species rely on smell to the same degree, most use their odor detection abilities extensively when compared to other reptiles. The unique snake tongue constantly samples the air and ground to give snakes a perpetual “map” of smells around them. This allows snakes to follow trails left by prey and potential mates while avoiding any predators in the area.
So the next time you see a snake flickering its tongue, you can be sure it is actively gathering precious olfactory information about its surroundings.