Bearded Dragon Femoral Pores: Nature’s Secret Messages

Now delving into our bearded dragons’ femoral pores, I hope to show you what an incredible role these little pores and glands play. Just like our beardies, many lizards have these little dots on the underside of their thighs.

These pores and the glands beneath them produce waxy secretions that are a mix of keratin, protein, and even some lipids—basically a bearded dragon’s very own cologne (Funk, 2002).

And guess what? Our bearded dragons’ femoral pores help them to communicate. As our beardie struts around, these secretions are left behind like breadcrumbs, helping them spread their “I was here” messages (Imparato et al., 2007). Of course, that can also be interpreted as ‘this spot is taken’ (territorial marking).

The scent from these waxy secretions can even give away secrets like whether ‘hey, I’m a great mate!’ (Mayerl et al., 2015). And because these secretions stick around for a while, they ensure that their messages don’t fade too quickly, keeping the dragon’s presence known (Imparato et al., 2007).

Through this amazing system of chemical communication, beardies and other lizards, maintain peace, protect their turf, and share important information. Who knew these little dots on our bearded dragons’ legs could do so much?

What are Bearded Dragon Femoral Pores?

Femoral pores are small dots found on the underside of our bearded dragon’s thighs. These dots lead to glands under the skin, called femoral glands. The glands produce a special waxy substance, called holocrine secretion, that carries chemical signals. The holocrine secretions are like a secret language for lizards (Witten, 1993; Mayerl et al., 2015).

Not all lizards are lucky enough to have these special pores, but bearded dragons do, thanks to their membership in the agamid lizard family (Witten, 1993).

Do you know what makes our bearded dragons femoral pores even cooler? The pores are perfectly placed to spread their secretions as they move, almost like writing their story on the ground (Imparato et al., 2007).

What are the Dots on my Bearded Dragons Legs?

Our bearded dragons femoral pores are those small, dot-like structures running along the underside of their thighs. Beneath these pores lie femoral glands that create waxy secretions carrying chemical messages—a secret code that other bearded dragons can understand (Witten, 1993; Mayerl et al., 2015).

These pores are lined with special scales to help the secretions get applied to surfaces as the lizard moves. It’s like leaving a personal stamp wherever they go—a stamp that other lizards can read and understand (Imparato et al., 2007).

The Anatomy of Femoral Pores

Imagine our bearded dragon’s thighs as secret passageways to a world of communication. Beneath those tiny dots, or femoral pores, lie special glands that produce a waxy substance with important messages.

These glands work in a fascinating four-step process: they create, store, break down, and finally release the waxy secretions. What you see on the outside of their femoral pores is the final step of this incredible cycle (Mayerl et al., 2015).

When the gland inside these pores makes the secretion, it fills up with this waxy stuff until the whole cell bursts and releases it. Although it sounds a bit gross, it’s a normal and important part of how they “talk” to other bearded dragons without making a sound, kind of like leaving a scented note for others to find.

The femoral pores (ducts) continuously and slowly release this thick waxy solid holocrine secretion known as a secretion plug (Imparato, 2007). The secretion in agamids is mostly protein (likely keratin), pheromones and other chemical compounds (Gans and Crews, 1992).

The pores form lines along our bearded dragon’s thighs, like rows of tiny portholes. In some species, like the Iberian rock lizard (Lacerta monticola), these pores open through modified scales or between them—an amazing adaptation that varies from species to species (Martín & López, 2000).

And here’s something fascinating—the special arrangement of cells inside these glands ensures the secretions stay intact and effective as they’re deposited (Imparato et al., 2007).

Not only are femoral pores functional, but they’re also unique identifiers. The number and arrangement of these pores differ across lizard species, making them a key feature for identifying different kinds of lizards (Baeckens et al., 2015).

Did you know that Lizards Femoral Pores Glow?

Here’s a fun fact to blow your mind! In some lizards, like the desert iguana, the secretions from their femoral pores can glow under UV light.

For our bearded dragon’s that means that their thighs light up like tiny stars! Scientists think this might be a way for lizards to make their chemical messages more visible to others (Funk, 2002).

But here’s the twist—this glowing magic isn’t just for show. It’s also a way for lizards to communicate more effectively, especially in environments where visibility matters.

Since other lizards can see the glow it might cause stress in lizards living together in close quarters. The dominant lizards marking their territory could overwhelm their companions with glowing signals (Funk, 2002).

Differences Between Male and Female Femoral Pores in Lizards

Femoral pores aren’t just a one-size-fits-all feature; they differ based on gender and serve specific purposes.

Male Bearded Dragon Femoral Pores

Mature male bearded dragon femoral pores are more than just little dots on their legs, they are quite pronounced. The femoral pores are one of the ways to if a bearded dragon is male or female because the males pores are much larger and more active than females.

A male bearded dragons femoral pores tend to become visible as they reach sexual maturity, typically around the one-year mark.

It’s not just male bearded dragons that have large femoral pores either, in Cole’s (1966) research, he spoke about how these glands are larger and more complex in male lizards in general.

During the breeding season, these pores go into overdrive, producing more waxy secretions. This is true for many lizard species, including the Iberian rock lizard (Martín & López, 2000).

Males use their femoral pores to mark territory and attract mates, leaving chemical “notes” to ward off rivals and woo potential partners. Cole’s (1966) findings reveal that male lizards’ glands are influenced by testosterone, which shows us that hormones have a role to play in the seasonal activity of femoral pores (Cole, 1966).

Do Female Bearded Dragons have Femoral Pores?

Female bearded dragons have femoral pores too, but theirs are a bit more low-key. They don’t produce as many waxy secretions, and their glands are smaller and less active than those of the males. However, these pores are far from insignificant.

Mayerl et al. (2015) suggest that female femoral pores might have their own special role to play during the mating season and that the glands only become active before mating. Their secretions could act as subtle signals, letting males know they’re ready to mingle and that they haven’t been mated yet. Think of it as the lizards version of a wink across the room.

Here’s the catch: there’s still a lot we don’t know about the femoral pores of female lizards. Researchers have pointed out that most studies focus on males, leaving the ladies somewhat in the shadows Mayerl et al. (2015). But this much is clear—these tiny pores are likely part of an intricate communication system that’s yet to be fully understood.

What Happens to Femoral Glands when you Castrate a Lizard?

But here’s a twist—it’s not their gender that makes the difference in the size of femoral pores, its their hormones. Androgens actually which is a group of hormones including testosterone.

When male lizards were castrated, their once-mighty femoral glands shrank and started resembling those of females. This showed just how important testosterone is in keeping these glands big and busy (Cole, 1966). However, castrating females had no effect. But when the scientists gave them two special chemicals called testosterone propionate and dihydrotestosterone, the lizards started making their waxy messages again (Norris and Lopez, 2011).

What Do Our Bearded Dragons Femoral Pores Do? Their many Roles

Femoral pores in bearded dragons are like their personal messaging system, producing a waxy substance packed with chemical signals known as pheromones. These pheromones are a lizards way of communicating with other lizards, sharing vital information about territory, identity, and even mating fitness.

Research on species like the Iberian rock lizard and common wall lizard (Podarcis muralis) sheds light on the fascinating role of these secretions, which provide two key types of information:

Territorial Communication: This is MY Turf!

Lizards can tell others “This is MY turf!” And that’s exactly what happens when they leave behind their waxy secretions. These chemical trails work like invisible boundary lines, telling other lizards to stay out (Brown, 2012; Aragón et al., 2001; Mayerl et al., 2015). It’s like a big “No Trespassing” sign made of beardie cologne!

But here’s something even cooler: Cole (1966) discovered that these secretions don’t just mark territory; they can also help lizards recognize their own scent marks. This means our beardies can save energy by avoiding areas they’ve already marked and focus on new territory instead.

Recognizing Others

The waxy secretions from femoral pores act like a bearded dragon’s ID card. When another lizard gets a whiff, it can tell who left the mark, whether they know them or not, or even a potential mate. This helps lizards to avoid unnecessary conflict and aggression in their social interactions (Mangiacotti et al., 2019; Mayerl et al., 2015; Aragón et al., 2001).

In some species, like the Iberian rock lizard, these secretions contain a mix of proteins and lipids that

And here’s the science behind the magic: femoral secretions contain both proteins and lipids that work together to convey nuanced messages.

• The proteins help individuals recognize each other and avoid unnecessary altercations.
• Lipids signal information about the lizard’s health, quality, fitness and age.

Together, they create a detailed chemical profile that’s as unique as a fingerprint and enable other lizards to make decisions about territory and potential rivals with remarkable precision. (Imparato et al., 2007; Mangiacotti et al., 2019; Aragón et al., 2001; Baeckens et al, 2015).

Bearded dragons likely use their femoral pores in the same way, navigating their social world with these invisible messages.

Male lizards have an additional layer of sophistication in their recognition abilities. They can differentiate their own secretions from those of other males. This remarkable skill helps them avoid marking the same areas repeatedly and instead focus on unfamiliar territories or competitors, conserving their energy and resources for more meaningful interactions (Aragón et al., 2001).

Attracting the Girls: Femoral Pores as Tinder for Bearded Dragons

Bearded dragon love lives are written in scent! Femoral pore secretions are like Tinder for lizards, except instead of swiping right, females rely on their sharp noses to decide if it’s love at first sniff.

Research reviewed by Mayerl et al. (2015) revealed just how much females can glean from these chemical cues. A single whiff can tell a female everything she needs to know about a male’s size, health, diet, and even his access to sunbathing spots. It’s like reading his resume—all in one sniff!

The female Psammodromus algirus lizards have shown just how skilled females are at picking the best mates. These ladies can sniff out males with fewer parasites and stronger immune systems, giving them a clear edge in choosing the healthiest and strongest partners (Mayerl et al., 2015).

But wait, there’s more! In some species, females can even detect and prefer males with essential nutrients, like vitamin E or oleic acid, in their secretions (Norris & López, 2011; Mayerl et al., 2015). I can only smell if my other half has been drinking beer!

Oh, and age matters too. Females often favor older males with more mature and established chemical profiles, proving that experience and wisdom really do come with age (Mayerl et al., 2015).

Studies on Iberian rock lizards revealed that looks matter to females. The females prefer males with more symmetrical femoral pores and high-quality secretions. These traits often mean the male is in top shape, with great genes to pass on (Martín & López, 2000).

Seasonal and Behavioral Changes in Bearded Dragon Femoral Pores

Bearded Dragons’ Femoral Pores During Brumation: Slowing Down for Winter

During brumation, activity in femoral pores slows down. This is likely because hormone levels drop during this time (Mayerl et al., 2015).

Bearded Dragon Femoral Pores in Mating Season: A Time for Action

During the mating season, male lizards produce more waxy secretions. This helps them attract mates and mark their territory. In species like the Iberian rock lizard, this increase in activity is linked to rising hormone levels, especially testosterone. Bearded dragons likely experience similar changes (Martín & López, 2000).

During breeding season the glands secrete more and increase in size however the pore size stays the same (Mayerl et al, 2015). The make up of the secretion also changes during breeding season.

How Substrates Shape Bearded Dragons’ Femoral Pores and Their Signals

The waxy secretion is smeared on substrate and objects such as rocks, branches and vegetation within the male’s territory. Small pieces of the femoral secretion plug fall off onto the substrate leaving a chemical signature.

In studies Tegu’s were observed rubbing their thighs and cloacal region on the ground. The femoral secretion left on the ground was not obvious enough to see by eye however, the reactions of other males indicated they could very much detect the previous males scent (Chamut, 2009).

Imagine a lizard scampering across a rocky outcrop, leaving tiny chemical “breadcrumbs” behind. These secretions, deposited from their femoral pores, serve as a message board for other lizards, letting them know who’s been there and what they’re claiming as their own. But not all habitats work the same way for these signals.

Regnier and Goodwin (cited in Baeckens, 2015) found that clay surfaces were slower to lose the scent than wood.

In rocky or sandy terrains, these chemical breadcrumbs tend to stick around longer, giving the lizards more bang for their buck when it comes to communication. This is why lizards in these environments often have more femoral pores—their signals are effective and worth the investment (Baeckens et al., 2014).

Quite a different story for lizards in dense, shrubby areas. Here, the wind rustles constantly, dispersing the chemical signals before they have a chance to linger. In these habitats, lizards might rely less on chemical communication and more on flashy visual signals, like head bobs or bright colors (Baeckens et al., 2014).

And then there’s evolution. Just like family traits passed down through generations, some lizards inherit their femoral pore patterns from their ancestors. These phylogenetic constraints mean that evolutionary history can shape femoral pore traits just as much as environmental needs (Baeckens et al., 2014).

The number and effectiveness of femoral pores in lizards can vary depending on the type of habitat they live in. Lizards that inhabit rocky or sandy terrains often have more femoral pores compared to those that live in shrubby or high-vegetation areas (Baeckens et al., 2014). The physical environment plays a key role in how these chemical signals are used and maintained.

In habitats with high vegetation, airflow can dilute the chemical signals faster, making them less effective. In these environments, some lizard species may adapt by relying less on chemical communication and more on other forms of signaling, such as visual displays (Baeckens et al., 2014).

Just like how some families pass down certain features like eye color, lizards inherit traits like femoral pore patterns from their ancestors. This shared ancestry, or phylogenetic constraint, means that a lizard’s evolutionary lineage can influence the number and placement of its femoral pores just as much as its environment does (Baeckens et al., 2014).

Bearded Dragon Femoral Pores: A Tale of Communication

Femoral pores are just little dots on our bearded dragons’ thighs but the impact of them on their lives is huge.

It is incredible how the waxy secretions for our bearded dragons’ femoral pores provides so much information, has such a large role communication for communication impacting their social interactions. Bearded dragon femoral pores are more than just tiny dots—they’re a window into their world. From marking territory to identifying mates, these pores are part of what makes our beardies unique and fascinating creatures. Who knew their thighs held such captivating secrets?

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References

• Aragón, P., López, P., & Martín, J. (2001). Discrimination of Femoral Gland Secretions from Familiar and Unfamiliar Conspecifics by Male Iberian Rock-Lizards, Lacerta monticola. Journal of Herpetology, 35(2), 346.
• Baeckens, S., Edwards, S., Huyghe, K., & Van Damme, R. (2014). Chemical signalling in lizards: an interspecific comparison of femoral pore numbers in Lacertidae. Biological Journal of the Linnean Society, 114(1), 44–57.
• Brown, D. (2012). A guide to– Australian dragons in captivity. Reptile.
• Chamut, S., Valdez, V. G., & Manes, M. E. (2009). Functional Morphology of Femoral Glands in the Tegu Lizard,Tupinambis merianae. Zoological Science, 26(4), 289–293.
• Cole, C. J. (1966). Femoral Glands in Lizards: A Review. Herpetologica, 22(3), 199–206. JSTOR.
• Funk, R. S. (2002). Lizard reproductive medicine and surgery. Veterinary Clinics of North America: Exotic Animal Practice, 5(3), 579–613.
• Imparato, B. A., Antoniazzi, M. M., Rodrigues, M. T., & Jared, C. (2007). Morphology of the femoral glands in the lizard Ameiva ameiva (teiidae) and their possible role in semiochemical dispersion. Journal of Morphology, 268(7), 636–648.
• Mangiacotti, M., Gaggiani, S., Coladonato, A. J., Scali, S., Zuffi, M. A. L., & Sacchi, R. (2019). First experimental evidence that proteins from femoral glands convey identity-related information in a lizard. Acta Ethologica, 22(1), 57–65.
• Martín, J., & López, P. (2000). Chemoreception, symmetry and mate choice in lizards. Proceedings of the Royal Society of London. Series B: Biological Sciences, 267(1450), 1265–1269.
• Mayerl, C., Baeckens, S., & Van Damme, R. (2015). Evolution and role of the follicular epidermal gland system in non-ophidian squamates. Amphibia-Reptilia, 36(3), 185–206.
• Norris, D. O., & Lopez, D. H. (2024). Hormones and Reproduction of Vertebrates, Volume 3. In Elsevier Shop (2nd ed.). Elsevier.
• Witten, G. J. (1993). Family Agamidae. In Fauna of Australia. Amphibia and Reptilia. C. J. Gasby, G. J. B. Ross, and P. L. Beesley (Eds.),. Australian Government Publishing Service, Canberra. 2A, 240–252.

References

1. Aragón, P., López, P., and Martín, J. (2001) Discrimination of Femoral Gland Secretions from Familiar and Unfamiliar Conspecifics by Male Iberian Rock-Lizards, Lacerta monticola. Journal of Herpetology. Vol. 35(2): 346-350
2. Baeckens, S., Edwards, E., Huyghe, K., & Van Damme, R. (2015) Chemical signalling in lizards: an interspecific comparison of femoral pore numbers in Lacertidae, Biological Journal of the Linnean Society. Vol 114 (1): 44–57
3. Baines, F. M. (2017). The veterinary care of the bearded dragon. British Veterinary Association.
4. Bowmanville Veterinary Clinic. Bowmanville, Ontario, Canada.
5. Brown, D. BVSc, BSc (2012) A Guide to Australian Dragons in Captivity. Reptile Publications. QLD Australia
6. Chamut, S., & Garcia Valdez, V., & Manes, M. (2009) Functional Morphology of Femoral Glands in the Tegu Lizard, Tupinambis merianae. Zoological science. 26. 289-93.
7. Cole, C. (1966) Femoral Glands in Lizards: A Review. Herpetologica, 22(3): 199-206.
8. Eatwell, K. (2010) Skin Issues in Lizards, Part Two: Approaching Disease Difficulties. Vet Times.
9. Funk, R. S. (2002). Lizard reproductive medicine and surgery. Veterinary Clinics of North America: Exotic Animal Practice, 5(3), 579–613.
10. Gans, C., and Crews, D. (1992) Hormones, Brain, and Behavior. Bibliovault OAI Repository, the University of Chicago Press
11. Imparato, B. A., Antoniazzi, M. M., Rodrigues, M. T., & Jared, C. (2007) Morphology of the femoral glands in the lizard Ameiva ameiva (teiidae) and their possible role in semiochemical dispersion. Journal of Morphology. Vol 268(7): 636-648
12. Klaphake, E. DVM, DACZM, DABVP (Avian Practice), DABVP (Reptile & Amphibian Practice) (UD) Femoral Gland Biology and Possible Medical Concerns in the Green Iguana, Iguana iguana.
13. Mangiacotti, M., Gaggiani, S., Coladonato, A. J., Scali, S., Zuffi, M. A. L., & Sacchi, R. (2019). First experimental evidence that proteins from femoral glands convey identity-related information in a lizard. Acta Ethologica, 22(1), 57–65.
14. Martín, J., & López, P. (2000). Chemoreception, symmetry and mate choice in lizards. Proceedings of the Royal Society of London. Series B: Biological Sciences, 267(1450), 1265–1269.
15. Mayerl, C., Baeckens, S., & Van Damme, R. (2015) Evolution and role of the follicular epidermal gland system in non-ophidian squamate. Amphibia-Reptilia 36: 185-206
16. Norris, D. O., & Lopez, K. H. (2011) Hormones and Reproduction of Vertebrates Vol. 3. Reptiles. San Diego, CA: Elsevier Academic Press Inc
17. Sollom, H., & Baron, H. (2023). Clinical presentation and disease prevalence of captive central bearded dragons ( Pogona vitticeps ) at veterinary clinics in Australia. Australian Veterinary Journal.
18. Stahl, S. J., & Donoghue, S. (2010). Nutrition and disease management for veterinary technicians and nurses. Wiley-Blackwell.
19. Witten, G. J. (1993) Family Agamidae. In Fauna of Australia. Vol 2A: Amphibia and Reptilia. C. J. Gasby, G. J. B. Ross, and P. L. Beesley (eds.), pp 240-252. Australian Government Publishing Service, Canberra.