Bearded dragons taste their food, but it’s a little different from how we do! Our beardies sense of taste is all about survival, helping them figure out what’s safe to eat and what to avoid.
Our bearded dragons taste buds (receptors actually) work together to decide if something is nutritious, delicious, or dangerous. Scientists like Feng and Liang (2018) have found that lizards can detect flavors like bitter and possibly sweet or savory (umami) tastes. This helps them choose foods that keep them healthy while steering clear of harmful ones.
Taste receptors and taste buds are not the same, but they work closely together to help our bearded dragons taste different flavors:
- Taste Buds: These are the larger structures that we can see on the tongue. Think of them as little hubs that hold the taste receptor cells.
- Taste Receptors: These are the proteins inside the taste buds that do the detective work. They sense specific flavors like sweet, savory (umami), or bitter, helping our bearded dragon’s taste and decide if something is worth eating.
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How Bearded Dragons Taste (and Other Reptiles)
Do bearded dragons taste the same way we do? Not exactly. We humans experience sweet, salty, sour, bitter, and umami flavors. Reptiles focus on the tastes that align with their dietary needs.
Lizards, including bearded dragons, have two primary groups of taste receptors: TAS2R and TAS1R. These receptors work together to help them detect a wide range of flavors, ensuring they avoid harmful foods and seek out nutritious ones (Nishihara et al., 2023).
Taste Receptors That Know Sweet and Savory Flavors: TAS1R
The TAS1R family specializes in detecting flavors linked to nutrients. Each member contributes uniquely: TAS1R1 and TAS1R3 for savory, TAS1R2 and TAS1R3 for sweet, and TAS1R4 to TAS1R6 for broad nutrient detection.
Think of this group as the treasure hunters of the taste world, helping our bearded dragons find the good stuff. Here’s how they break down:
- TAS1R1 and TAS1R3: These receptors work together to help bearded dragons taste savory (umami) flavors, often tied to amino acids found in protein-rich foods like insects.
- TAS1R2 and TAS1R3: This dynamic duo handles sweetness. Whether it’s the natural sugars in fruit or other energy-rich foods, these receptors guide bearded dragons tasting sweet treats.
- TAS1R4, TAS1R5, and TAS1R6: These newer additions broaden the flavor palette even further, helping bearded dragons can taste nutrients like amino acids and locate diverse, nutritious meals in the wild.
Taste Receptors that Detect Bitter: TAS2R
The TAS2R group is all about bitterness. Why is that important? In nature, bitter often signals danger—like toxins in plants or defensive chemicals in insects. TAS2R receptors are like bodyguards, giving lizards, like bearded dragons, the ability to avoid potentially harmful foods and substances. For example, when our bearded dragon turns its nose up at something, it might be these receptors kicking in, saying, “No thanks, that could be bad for me!”
How Does a Bearded Dragons Tasting Skills Stack Up Against Other Reptiles?
Who amongst reptiles has the sharpest sense of taste? Not sure that we know but research by Zhong et al. (2019) gives us some fascinating insights into how different reptiles measure up.
Our central bearded dragons taste receptors hold their own with 22 intact TAS2r genes and 3 partial ones, which help them detect bitter compounds. But why does the number matter? Think of it like tools in a toolbox—the more tools you have, the more problems you can solve. In this case, having more TAS2r genes means a reptile can detect a wider range of bitter compounds, which often signal toxins in plants and insects.
While 22 intact genes are impressive, the green anole takes a strong second place with 36 intact genes, giving it a more extensive ability to detect potentially harmful substances. The Japanese gecko, with its gold-medal-worthy 50 intact genes, has an even greater range, possibly because of its more diverse diet or unique environmental challenges. This diversity in receptor numbers reflects how each species’ diet and environment have shaped their taste systems over time.
So why don’t our bearded dragons lead the pack? It comes down to their balanced, varied diet. Unlike snakes, which mostly eat meat that doesn’t require much bitter detection, bearded dragons enjoy a mix of plants and insects, both of which can hide bitter chemicals. Their moderate number of bitter receptors lets them detect potential toxins without overloading their system. It’s all about balance—enough receptors to stay safe but not so many that their biology is overcomplicated.
Now snakes are a different story. Snakes are minimalist diners of the reptile world. Most snake species have just one or two intact TAS2r genes—or none at all. Why? Their diet of whole prey doesn’t involve bitter compounds, so their tongues focus more on gathering environmental cues through their vomeronasal organ—a fancy name for a scent-detection system.
Other reptiles, like the Burmese glass lizard and leopard gecko, sit somewhere in between. The Burmese glass lizard has just 3 intact TAS2r genes, reflecting its meat-focused menu, while the leopard gecko has 8, showing a slightly broader need for taste detection due to its insect-heavy diet.
What about crocodilians, like alligators? They keep it simple too. Their fish-and-meat diet doesn’t call for bitter detection, so their taste receptor system is much less developed compared to lizards.
These comparisons show how diet shapes taste receptor evolution across reptiles. And while our bearded dragons may not have the highest count of TAS2r genes, they’ve evolved just the right mix to thrive on their diverse menu of plants and insects.
So how do we humans compare to bearded dragons? Humans have about 25 intact Tas2r genes, which puts us on par with green anoles and slightly ahead of bearded dragons in bitter detection (Britannica, n.d.). But we humans also have thousands of taste buds with receptor cells that detect not just bitterness but also sweetness, sourness, saltiness, and umami flavors. This gives us a more complex and nuanced taste system overall (Britannica, n.d.).
Why Does My Bearded Dragon Like Some Foods and Not Others?
Some bearded dragons enjoy a variety of foods and scientists might have uncovered one of the reasons why! They recently found a unique taste receptor, TAS1R7, that’s only found in lizards and amphibians, including bearded dragons (Nishihara et al., 2023). This little receptor could be a secret superpower in helping our bearded dragons taste food differently from other animals.
While scientists aren’t entirely sure what TAS1R7 does yet, it might help bearded dragons detect flavors or nutrients in ways that guide their food choices. So, when your bearded dragon chomps on a cricket or munches on leafy greens, this receptor might be quietly working to answer the question: “Is this worth eating?”
Can Bearded Dragons Taste Sweet Things Like We Do?
Bearded dragons and other lizards have specialized taste receptors that help them detect certain flavors. Unlike humans, who experience sweet, salty, sour, bitter, and umami flavors, reptiles focus on flavors that align with their dietary needs. Studies show that many lizards, like the Madagascar giant day gecko, can sense sweet flavors through their TAS1R2–TAS1R3 receptors (Liang et al., 2022).
These TAS1R2–TAS1R3 receptors act like a taste alarm, picking up when they detect sugars like sucrose, glucose, or fructose. It’s as if our bearded dragon takes a bite of a juicy strawberry or a slice of mango, and their body says, “Yes, this is packed with energy!” We might notice their reaction when we give them a piece of watermelon or some blueberries, but they’re responding to the flavors that signal quick energy and essential nutrients.
Research by Nishihara et al. (2023) found that bearded dragons are among the lizards equipped with TAS1R receptors, including the fascinating TAS1R4. This receptor is like a built-in nutrient detector, specializing in savory (umami) flavors tied to amino acids found in protein-packed foods like crickets and mealworms. So, when our bearded dragons go wild for an insect feast, it’s not just hunger—it’s their TAS1R4 receptor recognizing the good stuff they need to stay healthy and strong.
For bearded dragons, this combination of sweet and savory detection might explain their love for sugary fruits and protein-packed insects. While there are no direct studies on bearded dragons specifically tasting sweetness, their shared genetic traits with other lizards suggest they likely enjoy sugary treats.
Why Does My Bearded Dragon Sometimes Reject Food?
Reptiles rely on taste, sight, and smell when deciding what to eat. Research suggests that bearded dragons have bitter taste receptors (TAS2r genes), like other lizards, to help them avoid toxic plants or insects. For instance, green anoles actively avoided bitter-tasting crickets in experiments (Stanger-Hall et al., 2001). Our bearded dragon might refuse certain foods if they detect bitter compounds, which can signal toxins. This natural ability is their way of staying safe!
Can Bearded Dragons Taste Proteins?
The umami taste, often associated with proteins, is another flavor reptiles may detect. Lizards retain TAS1r genes, which are responsible for sensing umami flavors (Feng & Liang, 2018). For bearded dragons, this could mean they have a preference for protein-rich insects like crickets and mealworms. This makes sense since these foods provide essential nutrients in their diet.
Why Do Bright Colors Get My Bearded Dragon’s Attention?
It’s not just about what our bearded dragons can taste, it’s also about how they see their food. Beardies are visual hunters, which means they rely heavily on sight when choosing their meals. Studies show that lizards can associate certain colors with flavors. For example, green anoles learned to avoid specific colors after associating them with bitter-tasting prey (Stanger-Hall et al., 2001). Our bearded dragons might be drawn to brightly colored foods like red bell peppers or strawberries because they stand out visually and signal something tasty.
What Helps Bearded Dragons Avoid Dangerous Foods?
Our bearded dragons can taste bitterness, and it plays a crucial role in their survival. Research shows that the central bearded dragon has 22 intact TAS2r genes, which help them detect bitterness far better than snakes, which only have about 2.4 on average (Zhong et al., 2019). This evolutionary difference reflects the diverse diets of these species.
Zhong et al. (2019) highlighted that lizards like bearded dragons need a broader set of TAS2r genes because of the variety of potentially toxic compounds in their diet. Snakes, which primarily consume meat and swallow prey whole, encounter fewer toxins and therefore have fewer TAS2r genes. In contrast, bearded dragons consume a mix of plants, vegetables, fruits, and insects, which may contain bitter-tasting compounds, necessitating a more developed system for detecting toxins.
However, bitter taste receptors don’t make bearded dragons avoid all bitter foods outright. Mildly bitter greens like dandelion, kale, and spinach are often eaten by bearded dragons. These foods contain low levels of bitter compounds that might not pose a significant risk and provide valuable nutrients.
When it comes to insects, the stakes are higher. Many insects, such as blister beetles and certain ants, produce strong bitter alkaloids as chemical defenses. Zhong et al. (2019) suggested that bitter taste receptors might help bearded dragons regulate their intake, enabling them to consume some mildly toxic insects in moderation while avoiding overindulgence that could lead to harm.
Bearded Dragons Taste a Variety of Foods
The discovery of TAS1R7 receptors suggests that bearded dragons might enjoy unique flavors beyond the standard sweet, bitter, and umami, so offering variety helps cater to their potential taste preferences (Nishihara et al., 2023).
How Evolution Shaped Bearded Dragon Taste Receptors
The variety and number of TAS2r and TAS1R genes in bearded dragons highlight how evolution has fine-tuned their sense of taste to match their diverse diet. Lizards that could detect both harmful and beneficial tastes were more likely to survive, avoiding toxic plants and insects while identifying nutritious foods (Zhong et al., 2019; Nishihara et al., 2023).
This evolutionary pattern is not unique to bearded dragons. Many other lizards, especially those with plant-heavy or insect-rich diets, have a larger set of taste receptor genes compared to strictly carnivorous reptiles. For example, snakes, which primarily consume non-toxic prey, have a simpler taste receptor system. In contrast, omnivorous lizards like bearded dragons needed more TAS2r genes to detect a wider range of potential toxins, as well as TAS1R genes to identify safe and nutritious foods.
The TAS1R genes, including TAS1R7 and TAS1R4, further support their ability to recognize sweet and savory (umami) flavors. This adaptation ensures that bearded dragons can find energy-rich fruits and protein-packed insects in their diet. In the wild, this balance between avoiding harmful foods and seeking out nutritious ones plays a vital role in their survival.
Why don’t we just call Taste Receptors by what they do Instead of TAS*#@?
Did you look at the taste receptors names and think to yourself, why do we have to have names like TAS1R? That’s not easy to remember. Wouldn’t it be so much simpler just to give them a name like the ‘bitter receptor’? But it turns out the naming isn’t really complex when we look at how they get their names.
TAS: TAS stands for ‘Taste Active Subtype’, indicating the receptors’ role in detecting flavors. Why didn’t the scientists just us TR then? Well, it was already used by other biology areas.
1R and 2R: These are just the classes of receptors:
- 1R (Class 1 Receptors) receptors are associated with detecting sweet and umami (savory) flavors. They are part of a broader family of G-protein coupled receptors (GPCRs), which are essential for signaling in taste perception.
- 2R (Class 2 Receptors) receptors are specialized for detecting bitter flavors, which are often associated with toxins.
Numbering (e.g., TAS1R1, TAS1R2): The numbers indicate the specific gene or receptor subtype within the TAS1R or TAS2R family. For example:
- TAS1R1 and TAS1R3 work together to detect umami.
- TAS1R2 and TAS1R3 work together to detect sweetness.
- TAS2R genes refer to multiple bitter-detecting receptors, each tuned to sense different bitter compounds.
Why Our Bearded Dragons Taste Matters
Understanding how our bearded dragon’s taste helps us keep them engaged with food and we can understand why some foods might be accepted while others are snubbed.
Here’s how we can use what we know about bearded dragons tasting their food:
- Give a variety of different tasting foods: Since bearded dragons may detect a range of flavors like bitter, sweet, and umami, mixing up their diet with different tasting foods will offer variety.
- Watch which foods they are rejecting: Notice what foods are being rejected and whether they may have a similar taste or perhaps even a bitter flavor which could signal toxins to them.
- Feed a rainbow of colors: Bearded dragons are visual eaters. We know that not just from talking about bearded dragons taste receptors but also because we know that lighting makes a difference to their desire to eat. Brightly colored veggies like red bell peppers or yellow squash can grab their attention and encourage them to eat.
- Be careful of feeding sweet foods: We know that bearded dragons enjoy eating fruit, and we can thank their sweet-detecting receptors for that. However, we also know that modern cultivars of fruits are bred for their sugar content and too much sugar isn’t good for their health.
Here are more great articles on bearded dragons anatomy and biology.
References
- Britannica. (n.d.). Chemoreception: The senses of taste and smell. Retrieved from https://www.britannica.com/science/chemoreception/The-senses-of-taste-and-smell
- Feng, P., & Liang, S. (2018). Molecular evolution of umami/sweet taste receptor genes in reptiles. PeerJ, 6, e5570.
- Liang, Q., et al. (2022). T1R2-mediated sweet sensing in a lizard. Current Biology, 32(R1287–R1303).
- Nishihara, H., et al. (2023). A vertebrate-wide catalogue of T1R receptors reveals diversity in taste perception. Nature Communications, 14, 456.
- Stanger-Hall, K. F., et al. (2001). Taste discrimination in a lizard (Anolis carolinensis, Polychrotidae). Copeia, 2001(2), 490–498.
- Zhong, H., et al. (2019). Characterization and phylogeny of bitter taste receptor genes (Tas2r) in Squamata. Genetica.
