Lizards may seem like strange creatures, but their urine can tell us a lot about their health, biology, and ecology. In this comprehensive guide, we’ll explore everything you ever wanted to know about lizard pee.
If you’re short on time, here’s the key point: Lizards produce nitrogenous waste in the form of uric acid, which allows them to conserve water in their dry environments. The characteristics of a lizard’s urine can reveal information about its hydration, reproductive status, and more.
In this nearly 3000 word guide, we’ll cover what lizard urine is made of, how they produce it, and what we can learn from studying it. We’ll explore urine’s role in communication, territorial marking, and temperature regulation.
And we’ll highlight some unusual facts, like exploding bladder syndrome in bearded dragons and projectile urine streams in chameleons.
The Composition and Creation of Lizard Pee
Uric Acid vs. Urea
Unlike mammals, most lizards excrete nitrogenous waste in the form of uric acid rather than urea. Uric acid requires less water to eliminate than urea, allowing lizards to conserve water more effectively (a handy trick for desert dwellers!).
The kidneys filter metabolic wastes from the bloodstream and produce a paste-like substance that contains up to 80% uric acid.
The Kidneys and Cloaca
The paired kidneys of lizards are located close to the cloaca, the common chamber that receives waste from the digestive, urinary, and reproductive systems. After urine is produced in the kidneys, it travels through ureters to the cloaca for storage until elimination.
When a lizard is ready to pee, muscles surrounding the cloaca contract to expel the paste-like urine. Fun fact: some arboreal geckos even have specialized cloacal muscles allowing them to accurately spray urine long distances!
Color and Viscosity
The characteristics of lizard urine can vary by species and health status. Color ranges from milky white to dark brown or even green. More concerning colors like red or black can indicate blood or parasites in the urine.
Viscosity ranges from liquidy to thick and paste-like depending on uric acid concentration. Abnormal viscosity warrants a trip to the vet.
Functions and Uses of Lizard Urine
Water Conservation
Lizards have developed some ingenious ways to conserve water through their urine. When water is scarce, some lizards can concentrate their urine to reduce water loss. For example, the Texas spiny lizard can concentrate its urine to be nearly 50 times more concentrated than the blood plasma.
This allows them to retain as much fluid as possible (1). Other lizards like the Desert Iguana have a bladder that can store large amounts of highly concentrated urine for days. The bladder acts as a water reservoir that can be drawn on when needed (2).
By producing little very concentrated urine, lizards can survive in hot, arid environments where water is hard to come by.
Scent Marking and Communication
Lizard urine contains pheromones and other chemical cues that communicate information to other lizards. Male lizards often use urine to mark territory and signal their dominance. For example, male Iguanas have a pair of salt glands on their heads that excrete excess salt, and the salts in their urine may carry individual odors that allow iguanas to recognize each other.
Males leave their scents around territory boundaries to ward off intruders (3).
In other cases, female lizards can identify the health, fitness, and social status of males through urinary pheromones and chemicals. This allows them to select the best possible mates. Amazingly, some lizards can even determine species, sex, and individual identity just from the chemical cues in urine!
Urine is like a “scent-based social media network” for lizards.
Temperature Regulation
Certain lizards are able to squirt urine for thermoregulation. The Australian Water Dragon can eject streams of urine from its cloaca to cool itself on hot days. Aimed at their hindlegs and tail, the urine evaporation helps lower their body temperature.
This is similar to how humans sweat to cool down. Other lizards like the Texas Spiny Lizard are known to dribble or spray urine on their legs to promote evaporative cooling (4). By judiciously getting rid of excess water through urination, lizards can finely control their body temperature.
Abnormal Lizard Urination and Health Issues
Dehydration
Dehydration is one of the most common causes of abnormal or infrequent urination in pet lizards. When lizards do not take in enough fluids, their bodies conserve water by producing little or highly concentrated urine.
Signs of dehydration include sunken eyes, lethargy, wrinkled skin, and lack of appetite. Providing fresh, clean water at all times and misting the tank daily can help prevent dehydration in captive lizards.
Bladder Stones
Bladder stones, also called uroliths, are rock-like deposits of minerals that form in the urinary tract of lizards. They often result from nutritional imbalances but can also be caused by infections or other health issues. Symptoms include difficulty urinating, blood in the urine, and straining.
Bladder stones must be surgically removed by a qualified exotic veterinarian. Preventative measures include feeding a balanced diet low in oxalates.
Infections
Bacterial, viral, parasitic, and fungal infections can all impact urinary function in lizards. Infections often cause symptoms like foul-smelling, discolored, or excessive urine production. Urinary tract infections require antibiotic medications prescribed by a vet.
Good husbandry such as sanitary housing, proper temperatures, and adequate hydration help prevent infectious diseases in captive reptiles.
Exploding Bladder Syndrome
Exploding bladder syndrome is a rare but potentially fatal condition seen in bearded dragons and certain other lizard species. It occurs when the bladder becomes blocked or obstructed for some reason, leading to an dangerous buildup of urine.
Without treatment, the bladder can literally rupture or explode internally! Symptoms include a hard, swollen abdomen and difficulty urinating. Surgery may be needed to correct exploding bladder syndrome if caught early.
Prevention focuses on proper hydration and ruling out underlying illness by an exotics vet.
Notable Lizard Urine Adaptations
Uromastyx Salt Glands
Uromastyx lizards, commonly known as spiny-tailed lizards or dabb lizards, have specialized salt glands located on their nasal passages that allow them to secrete excess salt they ingest from eating plants.
The salty fluid mixes with urine and is expelled as a means to maintain appropriate salt balance.
These unique glands, along with specialised kidneys, enable Uromastyx species to thrive in arid, inland deserts across North Africa and Asia where high salt content would normally pose a challenge for other lizards. Truly a noteworthy adaptation in the reptile world!
Chameleon Projectile Urine
Male chameleons have developed quite a nifty trick – the ability to shoot streams of urine up to 5 body lengths towards other males during territorial disputes! This hilarious yet effective display of urinary prowess occurs when two males spy each other in the trees.
Using specialised muscles around the pelvis and cloaca, the lizards can carefully aim and eject the urine jet in hopes of chasing the intruder away. Talk about taking the p*ss!
Komodo Dragon Toxic Pee
While Komodo dragon bites are rightly feared due to deadly bacteria, new research shows that the largest lizard’s urine is equally as dangerous. Komodos seem to have weaponized their pee as a noxious, toxic deterrent against rival dragons.
Studies found several harmful compounds absent in other lizards’ urine, causing scientists to hypothesize it evolved to discourage competitors from entering their scent-marked territories. One whiff of that acrid, ammonia-rich cocktail is enough to send any wise dragon the other way!
Studying and Collecting Lizard Urine
Lab Analysis
Analyzing lizard urine in the lab is critical for understanding the physiology and ecology of different lizard species. Researchers can collect urine samples from wild lizards or those kept temporarily in captivity. Here are some key methods for studying lizard urine in the lab:
- Urinalysis – examining urine composition like proteins, salts, and waste products provides insight into hydration status, kidney function, and metabolism.
- Hormone analysis – lizard urine contains reproductive hormones that can signal information about sexual maturity and breeding condition.
- Toxin analysis – some lizards sequester plant toxins in their bodies that get excreted, which can defend against predators.
- Stable isotope analysis – isotopic signatures in urine reflect diet composition and provide ecological information.
- Osmolality – measuring urine concentration helps understand how lizards conserve water in dry environments.
Researchers centrifuge and process urine samples, then utilize analytical techniques like mass spectrometry, immunoassays, and chromatography to study the compounds present. Proper storage and precautions help preserve urine composition following collection in the field.
Pheromone Research
Lizard urine contains pheromones used for chemical communication. By studying urinary pheromones in the lab, scientists can better understand lizard social behavior and chemical ecology.
Key research areas include:
- Species recognition – pheromones signal information on species identity, which is useful for mate selection and territorial behaviors.
- Sex identification – specific pheromones advertise sex to potential mates and rival males.
- Social status – dominant males often produce different pheromones than subordinates.
- Territorial marking – urinary pheromones play a key role in scent marking territories.
- Mate assessment – females may detect male quality through urinary pheromone cues to choose fitter mates.
Analyzing urine samples with gas chromatography-mass spectrometry can identify specific pheromone compounds. Testing behavioral responses provides insight into how lizards respond to these chemical signals.
For instance, scientists may expose a male lizard to female urine and observe its courtship behaviors.
Field Methods
Studying lizard urine in natural settings provides key ecological insights not captured in the lab. Field biologists use several techniques to collect and analyze lizard urine:
- Opportunistic sampling – collecting urine from handled lizards during ecological surveys.
- Enclosures – keeping wild lizards temporarily in mesh enclosures lined with clean substrate to collect urine.
- Squeeze sampling – applying gentle pressure to the abdomen sometimes causes urination which can be caught in a vial.
- Bladder tapping – inserting a needle into the bladder to aspirate urine samples.
- Pitfall traps – placing plastic sheeting in funnel traps captures urine from species that enter traps.
- Substrate analysis – testing soil samples from lizard microhabitats for urinary pheromones and metabolites.
Portable lab equipment like microcentrifuges and mini-spectrometers enable basic urine analysis in remote field sites. When combined with ecological data on location, time, climate, and behavior, field-collected urine samples provide key insights into wild lizard biology.
Conclusion
As we’ve explored, lizard urine may seem like a peculiar topic but it can reveal fascinating insights into lizard physiology, evolution, and ecology. From water conservation to chemical communication, pee plays a critical role for these reptiles.
And its analysis continues to uncover new scientific discoveries, from the toxic compounds in Komodo piss to reproductive signals encoded in gecko urine.
The next time you see a lizard let loose a stream, remember there’s more than meets the eye. Their pee may be tiny, but it can tell a big story about how lizards live and survive worldwide. After reading this guide, you’ll never look at lizard urine the same way again!
