Reptiles are a diverse and fascinating group of animals that have inhabited the earth for over 300 million years. They can be found on every continent except Antarctica and come in all shapes and sizes, from giant snakes and crocodiles to tiny geckos and lizards. But with so many different types of reptiles, how can you reliably identify one? Learning some key characteristics and behaviors of reptiles can help you distinguish a reptile from other types of animals. In this article, we will explore the main features that define reptiles and provide tips for identifying common reptile species.
Distinguishing Features of Reptiles
All reptiles share a few common physical traits that set them apart from mammals, birds, amphibians, and fish. These distinguishing reptilian features include:
– Scaly skin – The skin of all reptiles is covered in scales made of keratin, the same material that makes up human fingernails and hair. The scales protect the reptile’s body from the environment and predators.
– Cold-blooded – Unlike warm-blooded mammals and birds, reptiles cannot internally regulate their own body temperature. Their body temperature depends on external heat sources like sunlight. This is why reptiles often bask in the sun.
– Egg-laying – Rather than giving live birth, reptiles lay shelled eggs that hatch outside the mother’s body. The eggs have leathery or calcified shells to protect the embryos inside.
– Terrestrial lifestyle – Most reptiles live on land, unlike amphibians which need water to reproduce. Though some reptiles like snakes and turtles can swim, they typically cannot breathe underwater like fish can.
| Reptile Trait | Description |
|---|---|
| Scaly skin | Made of keratin scales that protect the body |
| Cold-blooded | Body temperature depends on external heat sources |
| Egg-laying | Lay shelled eggs rather than giving live birth |
| Terrestrial lifestyle | Live mostly on land rather than in water |
So if you observe an animal with dry, scaly skin, basking in the sun, that has laid a clutch of eggs, chances are you’ve encountered a reptile. Next, let’s look at some more specific identification tips.
Look for Physical Adaptations
Many reptiles have developed unique physical adaptations to help them survive and thrive in their environments. Observing these specialized features can provide clues to an animal’s identity. Some key things to look for include:
Scales – Pay attention to the size, shape, and texture of the scales. Large, bony scales often indicate a crocodilian. Small, smooth scales are common on snakes and legless lizards. Rough, textured scales may come from a lizard or horned toad.
Size and shape – Take note of the reptile’s size and proportions. A long, slender body suggests a snake or legless lizard while a short, compact body is more common for turtles. Observe the size and placement of the eyes, ears, legs, tail, and other body parts.
Color patterns – Many reptiles have distinctive markings and colors. Bright warning displays may indicate a venomous coral snake or Gila monster. Camouflage patterns like stripes, spots, or mottling can identify certain geckos, skinks, or vipers.
Specialized features – Horns, spines, frills, dewlaps, and other unique structures offer clues about a reptile’s identity and habitat. Desert species often have adaptations to deal with extreme heat. Aquatic reptiles may have webbed feet or a streamlined build.
Carefully noting these physical attributes and comparing them to guidebooks or online resources can help pin down what type of reptile you are observing. With experience, you’ll start to recognize the defining features of common species.
Watch Behavior and Habitat
In addition to physical features, a reptile’s behavior and habitat preferences can also aid identification. Here are some behavioral clues to look for:
– Basking – Most reptiles bask in the sun to regulate their body temperature. Take note of basking positions and times of day.
– Hiding spots – Observe where reptiles take shelter and retreat when disturbed. Hiding places reflect habitat.
– Movement – Legged reptiles like lizards tend to scurry quickly. Snakes rely on sideways slithering. Turtles and tortoises walk slowly.
– Defense – Monitor reactions to perceived threats. Hisses, puffed neck frills, tail vibrations, and lunging bites are common defensive behaviors.
– Diet – Insect-eating lizards stalk bugs while herbivorous iguanas browse vegetation. Watch for reptiles near food and water sources.
– Territory – Note evidence of territorial displays or aggression between competing individuals, common in some lizard species.
Take note of the habitat the reptile occupies. Aquatic turtles live in ponds, rivers, and streams. Desert reptiles frequent rocky outcroppings, sand dunes, or arroyos. Arboreal species climb shrubs and trees. Matching a reptile to its preferred environment can help pin down its identity.
Use a Field Guide
One of the best identification resources for reptiles is a quality field guide. Field guides offer detailed descriptions, range maps, and vivid photographs of reptile species you may encounter. They also organize reptiles by family so you can narrow down your search. For example, a snake-like reptile with smooth scales would be found in the sections on snakes and legless lizards.
Here are some top-rated regional field guides for North America:
– Peterson Field Guide to Reptiles and Amphibians
– Kaufman Field Guide to Reptiles of North America
– Stokes Beginner’s Guide to Reptiles
– National Audubon Society Field Guide to Reptiles and Amphibians
Field guides are available as books, but electronic mobile apps offer a handy interactive format. Popular options include the Audubon Reptiles and Amphibians app and the iNaturalist app’s built-in reptile identifier.
If you are traveling, research field guides specific to the reptiles in that region ahead of time. Having the right reference makes a huge difference for accurate identification.
Consider Consulting an Expert
In some cases, identifying a reptile can be tricky even for very experienced herpetologists (reptile and amphibian scientists). Subtle traits differentiate closely related or variable species. Venomous species can also be dangerous to handle or get too close to.
When in doubt, consult a reptile expert at a natural history museum, university, nature center, zoo, or aquarium. Send photos to them by email for help identifying the reptile. You can also post images on reptile internet forums or social media groups to crowdsource opinions.
Handling or approaching venomous reptiles is not recommended. Call animal control if you have safety concerns. Proper identification ensures you can take appropriate precautions around potentially dangerous species.
Key Tips to Remember
To summarize, here are the key strategies for identifying reptiles in the field:
– Look for distinguishing reptilian features like scales, egg-laying, and basking behavior
– Note physical traits like size, proportions, scales, color patterns, specialized adaptations
– Observe behavior including movement, feeding, defense, and territoriality
– Consider the habitat and environment the reptile occupies
– Use field guides and mobile apps to compare photos and descriptions
– Consult experts for help with tricky identifications or venomous species
With practice observing reptiles in the wild and comparing them to reference materials, you’ll gradually learn to recognize the most common species. Paying attention to key identification tips will give you the knowledge to distinguish reptile species with greater accuracy.
Identifying Common North American Reptiles
To give you an idea of how these identification principles apply, let’s take a closer look at distinguishing some widespread reptile species found across North America:
Garter Snake
Garter snakes have long skinny bodies with smooth scales and get their name from the three longitudinal stripes that run the length of their backs, resembling old-fashioned garters. Look for the yellow, brown, or greenish background color in between these stripes. Garter snakes have keeled scales, giving their skin a slightly rough texture. Average length is 18-26 inches. They are harmless to humans and common near water features where they feed on small fish, frogs, worms, and rodents.
Western Fence Lizard
The fence lizard gets its name from its habit of perching on fences, logs, and rocks. Medium-sized with a stout body and long tail, fence lizards have spiny scales on their backs and large scales on their bellies. Adult males have bright blue patches on their throats and bellies. Fence lizards do push-ups and bob their heads as territorial displays. They inhabit dry forests, shrublands, and backyards in western North America feeding on insects.
Eastern Box Turtle
As their name suggests, box turtles have a distinct box-shaped shell which is well-armored with thick scutes (bony plates). The upper shell is domed while the bottom shell is hinged to completely enclose the limbs and head. Box turtles have yellow, orange, or brown shell markings. Slow-moving and terrestrial, box turtles are frequently spotted wandering in forests, marshlands, and fields of eastern and central North America. They feed on worms, slugs, berries, mushrooms, and carrion.
American Alligator
American alligators inhabit freshwater wetlands across the southeastern U.S. A large, heavy-bodied crocodilian, their back is covered in bony osteoderm ridged scales. Alligators have a broad, rounded snout and typically stay smaller than 13 feet long. Young alligators eat fish, snails, crayfish, and insects while adults prey on mammals, turtles, waterfowl, and other reptiles. Look for alligators floating along the water’s edge waiting to ambush prey.
Desert Horned Lizard
This unique-looking lizard lives in arid habitats across the southwest. Identifying features include their rounded, flattened bodies covered in thorny scales, two large horns behind the eyes, and a crown of spines on the head. Coloration consists of stripes, spots, or a combination that blends into the desert background. When threatened, horned lizards can squirt a stream of foul-tasting blood from near their eyes. They feed mainly on ants.
Northern Water Snake
Common along eastern North American lakes, rivers, and streams, northern water snakes have brown, gray, or reddish bands across their stout bodies. Theirs scales have a dull, matte appearance. Northern water snakes are not venomous but will bite in self-defense, sometimes playing dead when harassed. Excellent swimmers, water snakes hunt for fish and amphibians at night as their prey sleeps. Watch for them coiled on branches above water.
Conclusion
Identifying reptiles starts with learning the unique physical and behavioral characteristics that distinguish them from other animal groups. Recognizing subtle traits like scale texture, hiding spots, and defensive displays takes practice. Using field guides, habitat clues, and consultation with experts can help confirm difficult identifications. Remember to focus on observation and photography, not handling, of reptiles to stay safe. With experience, you’ll be able to confidently identify reptiles by applying the tips outlined here. The diverse world of reptiles offers fascinating finds for nature lovers willing to learn their nuances.
