Despite not looking like it, yes, turtles are reptiles. Turtles, snakes, lizards, and crocodilians all belong to the Reptilia family, which means that they share a variety of characteristics.
Turtles belong to the Chelonia genus, family Cheloniidae, class Reptilia. The Chelonia genus divides into 2 suborders: Cryptodira and Pleurodira. Each of these divides into multiple other families with a vast number of different species with numerous characteristics.
What’s even more impressive is that the current classification of turtles is an ever-expanding field as we discover new information regarding these animals’ genetic material and variation.
So, today we will discuss turtles and how they fit in the Reptilia class. Let’s get to it!
Characteristics of Reptiles
Reptiles consist of a group of animals with distinct characteristics that separate them from other animal groups.
The main distinction between reptiles and other animals include:
- The presence of skin scales – Interestingly enough, reptiles aren’t the only ones with skin scales. The pangolin, which is a mammal, has large body scales to protect itself from predators. Most birds also have scales on their legs, which is a residual feature of the birds’ evolutionary journey. But no other group of animals, except fish, have scales covering the entire body. Snakes have keratin scales covering the entire body surface, providing protection against injuries and the elements and aiding in locomotion. The belly scales are responsible for the latter.
- The three-chambered heart – All reptiles possess three-chambered hearts, with the only exception being crocodilians, which have four chambers, the same as birds and mammals. The reptiles’ heart layout allows for better oxygen synthesis and energy conservation. This makes reptiles more resilient to nutrient deprivation. It explains why most reptiles can go months without food.
- The reproductive variation – Reptiles are the only group of animals that can be both oviparous and viviparous. Oviparous reptiles are those that reproduce via egg-laying. These include various species of geckos, iguanas, chameleons, and turtles. Viviparous reptiles produce live young, but they still reproduce via eggs. The difference is that the eggs hatch inside the female’s body, with only the hatchlings coming out. Some examples include vipers, boas, bearded dragons, and others. Even more, interestingly, some reptile species can change their reproductive method depending on the environmental conditions.
Another noticeable difference would be the cold-blooded classification. Reptiles cannot regulate their body temperature, so they depend on their environment for that.
Turtle Evolution and Classification
The turtle’s evolutionary story is still subject to speculation to some degree, but there are some hardcore facts to account for.
These fascinating animals have been around for at least 220 million years, which means that they’ve shared space with the dinosaurs. Turtles fall into the Chelonia genus and are divided into 2 suborders: Cryptodira and Pleurodira.
The modern turtle’s ancestor was similar but quite different than its successors at the same time. These ancient turtles had the same features, for the most part, except their shell was weaker and didn’t provide sufficient protection against predators.
It took the turtle millions of years to reach its current form and the outstanding variation between the different turtle species today is proof of the animal’s amazing adaptability.
Physical Differences Between Turtles and Other Reptiles
Turtles are a distinct category of reptiles, making them one of the most recognizable reptiles on the planet.
Here are some noticeable and unique characteristics that make turtles stand out:
- The shell – It’s only natural to mention the shell first, as this is the most noticeable feature. The shell is actually made up of a fused spine, ribs, and other bones, creating a hard exoskeleton designed to protect the turtle from predators and the elements. The shell actually comprises 2 parts: the carapace and the plastron. The carapace is the upper shell, and it is usually hard and round, designed to prevent predators from latching onto it. The plastron is typically flat, but it’s equally as durable. The flat design is to allow the turtle to walk and run uninhibited (yes, turtles can run.)
- The semi-aquatic limb structure – Turtles have short, stocky, powerful, and wide limbs, perfect for swimming and traversing the land at the same time. This semi-aquatic adaptation is seen in other reptiles as well, but never to the same degree. Many lizards can also swim when necessary, but most lizard species are land animals. So, they have longer and more agile legs, fitter for climbing and running. Turtles have wider legs for better contact with water and a more unusual anatomy, with the paws pointing outwards at an angle. This structure is useful both in swimming and when digging the shore for egg-laying purposes.
- The head – Turtles have a modified mouth that forms a hardened beak, allowing them to exhibit tremendous bite force. This is especially useful in omnivorous turtles and carnivorous turtles that have adapted to consume a variety of prey. Such an example is the North American snapping turtle, famous for its biting force, carnivorous diet, and aggressive demeanor.
Turtles possess numerous other distinctive characteristics, such as the ability to switch between herbivorous and omnivorous dietary plans depending on the available food.
Behavioral Differences Between Turtles and Other Reptiles
Turtles showcase a variety of behavioral differences in relation to other reptiles.
Such differences include:
- The natural defense mechanism – The shell, more specifically. Turtles can also swim away or run to avoid predators, but the shell is always the go-to defense tactic. That’s due to the turtles’ ability to retreat into their shells, making them inaccessible to a variety of predators. Humans, crocodiles, fish, and some mammals like raccoons and opossums can prey on adult and young turtles, but some turtle species are too big and powerful even for these predators.
- Lack of territorial behavior – Turtles are among the few reptiles that have no territorial behavior. That’s because they don’t stick to a specific area unless that area is rich in feeding opportunities. The moment the food becomes scarce, the turtle will simply leave elsewhere.
- Lack of social behavior – Most turtles lack any social behavior whatsoever. They only meet to mate and that’s about it. This is somewhat typical for reptiles in general, but turtles can take this behavior to the extreme. So much so that you can only find a handful of turtle species that exhibit some social behavior. Such is the case of the three-toed box turtle that prefers to live in groups and forms communities with other members of the same species.
- The confusing mating season – Turtles showcase varying mating behaviors, depending on the species. Some turtles mate every year, others mate several times per year, and others mate every 2-3 years. These reptiles typically react to changes in temperature and day length to determine when the time for mating is right.
Turtles may exhibit a variety of other differences, such as the equally confusing dietary behavior. Some turtles are exclusively herbivorous, others are carnivorous, and others are omnivorous.
Even more, interestingly, some turtles can change their feeding pattern depending on the available nutrients.
It’s not uncommon for herbivorous turtles to become omnivorous when pressed by the environment.
Turtles are unique animals with equally unique physiologies, behaviors, and temperaments.
Some are tamable and can thrive in captivity, while others prefer the wilderness as their main playground.
If you’re interested in pursuing a pet turtle, do your research beforehand. Many turtle species are protected due to their endangered or vulnerable status.