For many people, differentiating between a tortoise and an aquatic turtle is a tough call.
In any case, these shelled reptiles belong to the same order and they have features and characteristics that are strikingly similar. Furthermore, they bear almost the same look and demeanor.
Nevertheless, despite the close relation, tortoises and turtles have several differences that revolve around their habitat, diet, lifespan, reproduction and anatomy.
Notably, it is important for everyone to know these distinctions to protect that existence of these endangered animals. Misidentification of either animal could be detrimental to their way of life.
With that said, here are the main differences between a tortoise and an aquatic turtle.
Habitat and Geographical Distribution
You are more likely to come across a tortoise than an aquatic turtle. This is because tortoises are land dwellers while aquatic turtles live and spend most of their time in the water.
The only few occasions you may encounter aquatic turtles on land is when they are basking in the sun or a female turtle wants lay eggs.
Tortoises normally reside in a variety of dwellings ranging from tropical rainforests to arid areas. The only time they would come near water is when they need to quench their thirst.
Aquatic turtles on the other hand dwell exclusively in water, including oceans, freshwater lakes, rivers and ponds.
In terms of distribution, most tortoise species are found in Asia, Africa and some parts of the Americas. Their bodies are adapted to live in hot conditions common in these regions.
Conversely, turtles are common in Africa and America where tropical and semi-tropical climates are more prevalent. The warm external conditions in these climate areas are ideal for regulating body temperature, given that they are cold-blooded reptiles.
During very cold weather, turtles may hibernate by burrowing themselves in the sand at the shores of the ocean or alongside the riverbank.
Tortoises rarely hibernate, but they may burrow themselves in the soil too if the weather gets too hot or cold. Some species of tortoises may also limit their metabolic rate during hunger-stricken seasons.
Shell Shape and Appearance
Both tortoises and aquatic turtles have a shell that shields the body from different forms of harm. The upper part of the shell is the carapace while the lower part is the plastron.
These two parts are attached by a bridge, from which the limbs and the head of the animals protrude. In case of danger, the tortoise or turtle may withdraw the limbs and head safely into the shell.
At first glance, the shell of a tortoise and a turtle might seem alike, but in actual sense, they are very much different. The shell of a tortoise is larger and heavier compared to that of a turtle.
Moreover, it has a dome shape and it is much bumpier to protect the tortoise from harsh weather and predators.
In contrast, the shell of an aquatic turtle is smooth, lightweight, flat and streamlined. Turtles have flat shells since they spend most of their time swimming in the water.
The flat, streamlined shape therefore comes in handy in breaking resistance while in the water.
In terms of weight and physical appearance, tortoises are much larger and heavier. Their limbs are short and sturdy and they have bent legs adapted to maneuver through various terrains.
Moreover, the legs of a tortoise are directly underneath the body.
Turtles on the other hand have webbed feet that look like full-fledged flippers. This makes them better equipped for their aquatic environment and for swimming.
They also have very long claws that come in handy for gripping floating logs and moving in marshy areas. The claws also help female turtles dig burrows used for laying eggs.
One intriguing characteristic about tortoises and turtles is that they have a very long lifespan. The life expectancy of these reclusive animals is more than 100 years.
Tortoises have the longest life span with most species living an average of 80 to 150 years. According to reports, the oldest living tortoise is 188 years old and he can be found is Saint Helena island in Seychelles.
Other records suggest that the oldest tortoise lived to 255 years while other unverified reports suggest that the oldest tortoise in history was 326 years.
Regardless of the validity of these reports, there is no doubt that tortoises can live more than 100 years if the environment is conducive. This is particularly true for those tortoises that are in controlled captivity, away from predators and other harsh conditions.
Turtles also have a long lifespan, but it does not compare to that of a tortoise. The common lifespan of an aquatic turtle ranges from 20 years to 70 years, depending on the species.
Sea turtles can survive for up to 86 years, but require about 50 years to mature into adult turtles. Reports that turtles could live forever are all but a fallacy.
One possible reason why aquatic turtles do not live for long has to do with the numerous predators such as sharks and dolphins that they have to face in their lifetime.
Humans are also one of the greatest threats to the survival of aquatic turtles. With this in mind, it is not surprising that turtles are among the listed endangered species in the world.
Reproduction and Birth
The reproduction process of tortoises and turtles are quite different. While female tortoises mature sexually from nine years of age, female turtles take only 5 years to reach sexual maturity.
Mating for both tortoises and turtles takes place on land as well as the laying of the eggs.
Notably, a female tortoise would lay about 5-7 fertilized eggs after every mating season. The tortoise will dig holes in the sand measuring 10 to 12 cm deep and lay her eggs there.
The incubation period ranges from 90 to 120 days depending on the species of the tortoise. Once hatched, the hatchlings will stay with their mother for 80 days before leaving the nest.
Aquatic turtles also lay their eggs on land, especially in sandy areas. Just like the female tortoise, the turtle will dig burrows in the sand where she will lay her eggs.
However, the holes are much deeper, measuring about 50 cm. The process of burrowing is secretive and normally takes place at night.
Unlike tortoises, which only lay 5-12 eggs at a time, female turtles can lay 50-100 eggs at a time. Interestingly, some aquatic turtle species are known to lay up to 300 eggs.
The incubation period takes about 40 to 70 days until the hatchlings are born. The temperature of the sand during the incubation period largely determines the sex of the turtle.
High temperatures result in female turtles while cold temperatures lead to male hatchlings.
One major difference as far as reproduction of these reptiles is concerned is that female turtles do not take care of their hatchlings.
The mother turtle will leave the nest immediately after laying eggs. This means that the hatchlings will have to fend for themselves after they are born.
Another interesting fact about aquatic turtles is that they normally return to lay their eggs on the same spot they were born.
The reason for this remains unclear but experts believe that hatchlings born in the same place as their mother are more likely to survive.
While tortoises and turtles belong to the same order, their diet is comparatively different. Tortoises are exclusively herbivorous. They feed on plants, shrubs, leaves, fruits, roots and herbs.
However, some studies suggest that some tortoise species can feed on meat and live insects such as beetles and caterpillars.
Turtles on the other hand are omnivorous just like humans. They feed on plants as well as meat. Some turtles are carnivorous but aquatic turtles prefer to remain omnivorous.
They have scissor-like jaws that are able to crush, munch and masticate a wide range of foodstuffs. Their preferred diet includes seagrasses, sponges, shrimp, cuttlefish, squid, algae, jellyfish, crabs and sea cucumbers.
Interestingly, some types of aquatic turtles feed on small mammals, snakes, frogs, snails and fish.
One intriguing aspect about both tortoises and turtles is that they can survive for days without eating. These reptiles have a wait of reducing the metabolism rate particularly when there is little or no food.
Moreover, turtles can hibernate for a few weeks without eating, especially during the cold seasons, when the weather is bad and there is no food to eat.
Both tortoises and turtles make good pets. However, it is much easier to keep a tortoise as a pet compared to keeping a turtle. This is because tortoises can survive on land easily, while you have to create a pool to keep a turtle.
Moreover, you have to drain and maintain the pool frequently to protect the turtle from diseases. From the look of things, this might prove to be costly and it requires total commitment.
Considering this, it is best to leave these animals in their natural habitats.
Knowing the differences between a tortoise and an aquatic turtle does not have to be a challenge.
You only need to look at the limbs, the shell, the size and appearance to distinguish one from the other.
Having the right information at your disposal may help in conservation efforts and protect these reclusive reptiles from becoming extinct.