Green Sea Turtle on lava, Big Island, HI
There are 360 species of turtles and tortoises on our planet, and they all fall under the same family Order: Testudines. These reptiles are unique creatures with many fascinating features.
Green Sea Turtle, Big Island, HI
We will look at a few of the major similarities and differences between turtles and tortoises. Nomenclature for these animals varies among countries; we won’t go into that here.
The fundamental difference between turtles and tortoises is where they live–land or water–and how their bodies have evolved to accommodate their environment.
Some of the ways turtles and tortoises are alike: both are cold-blooded (like all reptiles), lay their eggs on land, and have air-breathing lungs.
Just like their lizard cousins, turtles and tortoises need the sun to thermoregulate. Many of us have witnessed this sight before.
4 Pond Turtles at J.N. Ding Darling NWR, Florida
The carapaces (shells) of turtles and tortoises differ somewhat. But for both, the carapace is a permanent body part, it is never shed.
There are many of Earth’s creatures that have carapaces: armadillos, shell fish, crabs, most mollusks, beetles, and more.
Galapagos Sally Lightfoot Crab
But turtles and tortoises are the only reptiles with a shell.
Derived from bone, the carapace is permanently connected to the spine and ribs. During development, the ribs grow sideways and enter the animal’s skin, and then develop into broad, flat plates. They form their own personal armor.
More info: Turtle Wikipedia and Tortoise Wikipedia
Interesting Chart showing common species of turtles, tortoises, and terrapins.
And a few of the ways turtles and tortoises differ….
A turtle’s carapace is relatively flat and thin to help with diving and swimming. Small turtles have feet that are webbed or clawed to aid in swimming and climbing onto rocks.
Florida Cooter Turtle, GA
Large turtles have flippers, as you can see (below).
Sea Turtle, Hawaii
This turtle, below, doesn’t have a full, hard shell (like most). It is classified as a softshell turtle because the carapace is not fully bone. In the center it has a layer of bone, while the edges are made of cartilage and are leathery. It allows them to move more flexibly on muddy lake bottoms, and more quickly on land.
Florida Softshell Turtle, Okefenokee, GA
Sea turtles are one of my favorite creatures on earth. There are seven species in the world. In the U.S. we have six species and all are listed as endangered or threatened. Much work has been done to protect our big sea turtles, but there is still a lot left to do to ensure their survival.
Just like the smaller turtles, sea turtles live mostly in the water, coming to shore to bask in the sunshine and/or lay eggs in the sand.
Under water the sea turtles glide with beauty, ease and speed. They are omnivores and spend their submerged time foraging on sea grass, like this one below, as well as jellies and invertebrates.
Green Sea Turtle, Hol Chan Reserve, Belize
But turtles breathe air and must surface at regular intervals to refill their lungs.
They labor on land, moving slowly and awkwardly. They use their flippers as best they can, but the earth is not water.
Green Sea Turtle, Big Island, HI
Sea turtles are about four feet long (1.2 m) and weigh up to 400 pounds (181 kg). They generally live about 80 years.
So turtles are omnivores and built to swim and flourish in the water.
Conversely, tortoises are strictly land creatures. They cannot swim.
Their carapaces are heavy and domed for protection against predators. Their legs are short and sturdy to accommodate the heft. Their feet are padded and stumpy, and the front legs are scaled to protect the tortoise while burrowing.
We found this gopher tortoise while visiting the Jacksonville Botanical Gardens. It was about the size of a dinner plate. We were surprised at how quickly it was moving because tortoises are generally very slow. Things to do.
Gopher Tortoise on the move, FL
There is dispute about how far back into the ages turtles and tortoises go. But it doesn’t take a scientist to look at their ancient faces and see they are very old creatures.
And that brings us to the longest living land animal in the world: the Giant Tortoise.
While many of the Giant Tortoise species are now extinct, we still have a few living species on remote islands in the Seychelles and Galapagos.
I was fortunate to visit the Charles Darwin Research Station on the Galapagos Islands, where they have a breeding program and conservation practices for the perpetuation of the Giant Tortoise. To date there are 16 separate populations on ten of the largest Galapagos Islands.
We spent the afternoon in the highlands of Santa Cruz Island (Galapagos), where we came upon several of these most mesmerizing and magnificent creatures.
They have an average lifespan of 90-100 years, though there are records of some living longer, up to 188 years. They are herbivores, foraging on grasses, cacti, and fruit; and move very, very slowly.
We patiently and appreciatively watched this Galapagos Tortoise on the trail. It took about 20 minutes for it to travel 60 feet (18 m).
Galapagos Tortoise, Santa Cruz Island
They are the Granddaddy of all tortoises, some weighing up to 919 pounds (417 kg).
Galapagos Tortoise, Santa Cruz Is.
That day it was quiet in the highland forest, and the tortoises were docile. Except for one sound.
They can pull their heads into their carapaces, like many tortoises and turtles, and when they do the most astounding thing happens. This slow and quiet animal releases a loud hissing sound.
The hiss is the result of the individual releasing the air in its lungs to make room inside the shell for the head.
We came upon these three Galapagos Tortoises sleeping in the mud, while ducks paddled and frigatebirds circled overhead.
The sleeping tortoises looked like boulders.
Galapagos Tortoises, Santa Cruz Island
Every few minutes, a frigatebird, one of Earth’s largest sea birds, would dip its bill into the pond and take a sip.
Male Frigatebird overhead, Santa Cruz Isl.
For more info about Turtle and Tortoises differences click here — Turtle vs. Tortoise.
Turtles and tortoises, several hundred different species on our planet. They use the sun to create their energy and walk through life with a shell on their back. That is one unusual and beautiful being.
Written by Jet Eliot.
All photos in the wild by Athena Alexander.
Green Sea Turtles on lava rocks, Big Island, HI
Jet Eliot 