Why Do Reptiles Eat Their Shed Skin?
Reptiles shedding and consuming their old skin is a bizarre habit that puzzles many owners. After all, it seems pretty gross to humans. However, there are some very good reasons for this reptilian recycling behavior.
Below we’ll explore the benefits of skin eating for reptiles and why the behavior likely evolved. We’ll also answer common questions reptile owners have about managing sheds.
The Shedding Process
First, let’s quickly recap the shedding process. As reptiles grow, their outer skin layer called the epidermis reaches a growth limit. A new layer forms underneath, which causes the old external skin to die and separate.
Shedding allows reptiles to literally crawl out of their too-small skin as they grow. The skin comes off in patches or one whole piece. The shedding frequency varies based on factors like:
- Age – younger reptiles shed more as they grow
- Species – snakes shed more often than lizards
- Diet – well-nourished reptiles shed more frequently
- Environment – dry air and heat speeds shedding
This regular shedding is crucial for maintaining healthy scales or scutes. It allows removal of dead tissue, parasites, bacteria, and lets new skin better fit the reptile’s increasing size.
Now let’s look at why reptiles frequently turn around and eat their freshly shed skin after going through all that work to remove it!
BENEFITS
It Provides a Nutritious Snack
While it seems gross to us, shed skin actually provides a nutritious boost of protein and minerals for reptiles.
The protein-rich skin contains concentrated amounts of amino acids and collagen that are challenging for reptiles to synthesize internally. So they essentially recycle these compounds by ingesting the dead tissue.
Skin also contains many important minerals including calcium, phosphorus, magnesium and iron. Re-consuming these helps replenish the reptile’s nutrient stores after the demands of new skin growth.
So while it seems distasteful, eating shed skin helps reptiles reap the full benefits of their growth process. It lets them efficiently recoup and reuse the precious resources invested in the shed tissue.
Eating Skin May Bolster the Immune System
Another theory around the behavior is that consuming shed skin bolsters the reptile’s immune defenses.
When skin is shed, it takes with it skin-dwelling parasites and potentially harmful bacteria. By eating this shed skin, some researchers propose that reptiles re-ingest moderate levels of pathogens. This regular exposure continually stimulates their immune system and maintains optimal function.
It works on the basic premise of vaccines – controlled introduction of weakened pathogens trains the body’s defenses. So eating their shed skin may work like a natural booster shot for reptiles’ immune systems.
More research is still needed to confirm this idea. But it offers one possible evolutionary explanation for the peculiar habit beyond just nutrition.
The Behavior Has Deep Evolutionary Roots
In fact, the roots of reptilian shed-skin eating likely go back hundreds of millions of years. Some of the earliest tetrapod vertebrates and marine fish are believed to have consumed their sloughed-off skin and scales.
This includes ancestors of modern reptiles like amphibians and primitive synapsids that eventually gave rise to mammals.
So the instinctive behavior traces back to early evolutionary origins, suggesting an advantageous role in survival and adaptation. Any detrimental effects would have led natural selection to weed out the habit.
The behavior became intrinsically embedded within reptile physiology and still persists in diverse modern species. Even reptiles raised in sterile captivity retain the instinct to eat their shed skins.
Shed Skin Eating in Snakes
One of the most famous examples of reptilian shed-skin eating are snakes. As hunters reliant on stealth, snakes have evolved to eat their entire shed “suits” in one piece when possible.
This serves a few key functions:
- Camouflage – Eliminates traces that could reveal snake hideouts to prey or predators.
- Adds nutrition – Provides protein and minerals as mentioned earlier.
- Removes scent – Takes away skin that retained snake odors revealing their presence.
- Cleans habitat – Stops shed skins cluttering up small burrows and crevices.
For snakes, the advantages clearly outweigh any perceived grossness on our part. Rattlesnakes in particular have been documented eating their shed skins immediately after loosening them from the tail end first.
Pythons may go a step further by rubbing against rough surfaces to help loosen and peel off their skin. They then stretch their flexible jaws wide to ingest the entire sloughed sheath in one gulp!
Lizard Skin Consumption
Lizards also commonly eat their shed skins, but are a bit messier than snakes. Without flexible jaws, lizards tend to bite off pieces and swallow them gradually. Smaller lizards may devour their entire shed, while larger ones eat only partial pieces.
Certain groups like chameleons and geckos even deliberately chew off and consume bits of their skin before it fully loosens and sheds. This helps speed the shedding process while still gleaning some nutritional benefit.
No matter the exact method, the powerful instinct to eat shed skin remains strong in lizards. Some reasons it persists include:
- Recovery of nutrients invested in shed layers
- Removes evidence of their presence for predators
- Keeps their habitat clean of discarded skins
- Possible immune boosting properties
So while it seems foreign and distasteful to us, it makes perfect sense from the reptile physiological perspective.
Turtles and Skin-Eating Instincts
Even turtles and tortoises exhibit fascination with their shed scutes, the bony plates making up their shells. They can’t reach around to eat the scutes, but still eagerly sniff and bite at them after shedding.
This instinctive attraction to shed skin still manifests even in the modified shells of turtles. Some theories suggest that ancestral turtles had softer shells and consumed shed layers for nutrition.
In marine turtles, eating algae growing on shed scutes may also supplement their diet. The ingrained behavior to eat their shells remains even though the keratin provides minimal nutrition.
So in all reptiles, we still see remnants of this ancient survival behavior related to skin consumption. It remains deeply rooted even when practical utility is reduced.
Potential Risks of Eating Shed Skin
While natural behavior, eating shed skin does come with some risks that owners should be aware of:
- Bacteria – Shedding removes harmful skin bacteria, which can be re-ingested if the skin is eaten. This usually isn’t an issue in healthy reptiles with good gut flora balance. But overeating shed skin could tax digestive systems.
- Parasites – Mites or other parasites living on the old skin could be consumed and reintroduced into the body. This is another reason to practice moderation.
- Impaction – Swallowing too much rigid snake skin or turtle shell material could potentially cause gut impactions or constipation. Drink plenty of water and limit consumption.
- Toxic accumulation – Environmental toxins and pesticides accumulated in the skin cells could become concentrated in the shed layer. Eating too much shed skin could potentially reintroduce these harmful chemicals. Try to minimize exposure for your pets.
While an innate behavior, reptile owners should still exercise some caution and moderation when it comes to skin eating. Communicate with your vet if you have particular concerns.
FAQs – Managing Reptile Shedding
Here are answers to some common questions about reptile shedding and eating behavior:
Is it safe for my bearded dragon to eat its skin?
Yes, bearded dragons can safely eat modest amounts of their shed skin to recover nutrients. Just avoid too much as it may cause constipation. Make sure to provide proper heat and hydration to support healthy shedding.
Why does my leopard gecko eat the shed skins of other geckos?
This is normal social behavior in communal species. Dominant geckos will consume the sheds of rivals to hide their scent and presence. It’s a territorial dominance display. Provide multiple hide spots and make sure all geckos are well-fed to minimize competition stress.
How can I help my pet snake have complete sheds?
Maintain proper humidity in the snake enclosure, provide soaking opportunities, and offer rough surfaces to rub against. Before shedding, avoid handling and feeding to prevent regurgitation. Patience is required as removing stuck shed can damage new skin. Most will shed completely on their own given ideal conditions.
What causes my crested gecko to have patchy, incomplete sheds?
Dry air lacking sufficient humidity tends to create piecemeal sheds in crested geckos. Make sure to mist adequately and provide moist hide areas. Using a humid hide box can help remedy incomplete shedding during dry seasons.
Why does my leopard gecko eat its skin right after shedding?
Like other geckos, leopard geckos have adapted to eat shed skins immediately to hide evidence from predators. It also allows them to gain back beneficial nutrients before the old skin decomposes. Quick consumption is normal gecko behavior.
Are partial turtle shell scutes harmful if eaten?
Eating small bits of their shell after shedding is harmless for most turtles and tortoises. Just avoid excessive consumption, as impaction could occur from swallowing too much rigid material. It’s generally fine if they nip off some pieces out of instinct.
How often do ball pythons shed their skin?
On average, younger ball pythons tend to shed every 4-6 weeks, while adults shed about every 2-3 months. But this can vary based on feeding frequency, growth rates, time of year, and overall health. More frequent shedding is normal for rapidly growing juveniles.
I hope these tips help explain why reptile skin eating is an important natural behavior, not just a gross quirk! Let me know if you have any other reptile shedding or diet questions.