Facts About Turtles and Tortoises: Test Your Chelonian Knowledge

Facts About Turtles and Tortoises

Is this a turtle or tortoise? It depends on where you live. Photo by adrianam13/Bigstockphoto.com

You may know the most basic facts about turtles and tortoises. They are reptiles, have shells, can live on land or in water, and have scales on their skin. But did you know that turtles are aquatic reptiles with shells only if you live in the U.S.?

The term “turtle” is not actually a scientific name associated with a specific group of animals. It’s only a common name with a definition that changes as you travel the world.  In the U.S. turtles live in or near the water and tortoises live on the land and in the desert. The British call freshwater shelled reptiles “terrapins,” saltwater shelled reptiles are “turtles,” and land loving shelled reptiles are tortoises. Australians call only sea living shelled reptiles “turtles” and all others, from freshwater to land, are “tortoises.”

Confused? The worldwide multiple definitions of the common term “turtle” are a perfect example as to why scientists use scientific names, of which there can only be one, to name animals and plants. Read on for more scientific, interesting, and fun facts about turtles and tortoises.

Scientific Classification of Turtles and Tortoises

All turtles, tortoises, and terrapins are members of the reptilian scientific order Testudines. Within that order are 11 families. Ten of these families include species commonly referred to as turtles in the U.S. One family includes all the tortoises, the Testundinidae family.

Or Call Them Chelonians

Both scientists and turtle and tortoise enthusiasts also refer to the Testudines group as Chelonia, a reference to modern day turtles and tortoises that are separated from more prehistoric shelled reptiles. Therefore, a true turtle and tortoise enthusiast will refer to them collectively as chelonians.

Turtle Terminology

If you are going to learn about turtles and tortoises, you’ll need to know some basic terms.

Carapace – the upper shell.

Plastron – the bottom shell.

Beak – turtles and tortoises don’t have teeth, they have a beak. The beak may look harmless enough, but ask any turtle or tortoise keeper who’s made the wrong move and they will tell you the beak is exceptionally strong. And it does not willing let go of fingers when angered.

Scutes – sections of the shell that look like puzzle pieces and give the shell its pattern. The pattern of scutes on a shell are unique to each species.

Pyramiding – abnormal growth of pyramids on the carapace. This occurs in many pet tortoises from being fed an improper diet.

Salmonella – bacteria carried by chelonians and transmittable to humans. (Wash your hands after handling chelonians.)

turtle information book

Turtles of the World is an excellent turtle and tortoise resource book that you can buy on Amazon.

Largest and Smallest Turtles and Tortoises

Turtles and tortoises are measured by the length of their upper shell, the carapace. Animal Diversity Web reports that the largest turtle species is the leatherback sea turtle (Dermochelys coriacea). The National Museum Cardiff in the U.K. has a specimen that was 2,016 pounds when alive.

One of the smallest chelonians is the speckled cape tortoise (Homopus signatus), according to Turtles of the World. Its carapace measures at most 4 inches in length.

Facts About Turtles’ and Tortoises’ Longevity

Maybe it’s their slow-paced life style or healthy and mostly vegetarian diet, but these reptiles are the longest living animals. General Care and Maintenance of Popular Tortoises reports that a Greek tortoise holds the record for living 127 years. Living 20 to 100 years is not uncommon for a turtle or tortoise depending on the species. Leatherback turtles are known to live to 100 years or more. The American box turtle (Terrapene carolina), a common pet, can also live over 100 years.

Some Interesting and Fun Facts About Turtles and Tortoises:

The African spurred tortoise, aka sulcata, takes up to 24 years to become sexually mature adults.

The Swinhoe’s soft-shell turtle (Rafetus swinhoei) is the most endangered of turtles. As of 2004, only six individuals were known to be alive. That number dwindled to four in 2011. One is at least 80 years old, about 400 pounds, and lives in Hoan Kiem Lake in Vietnam where it is considered a sacred mythical creature and looked after by the community.

Larger turtle and tortoise species live longer than smaller species.

Chelonians are trainable. There’s no need to lift a 200 pound sulcata to move it. You can train it to walk from an outdoor enclosure to its nighttime indoor quarters.

Most males have a curved plastron, to fit comfortably over the female’s carapace when mating.

Incubation of eggs has a major impact on the development of the chelonian. In most species, low temperatures develop clutches of all or mostly males. Higher temperatures develop all or mostly females. Higher temperatures can reduce the incubation time by half, but too high and the eggs will die.

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