Many places in the world have sea turtles, which live in the ocean, and freshwater turtles, which live on land, often in lakes and rivers. These two types of turtles have significant morphological differences. Sea turtles have flippers instead of hands and feet. Those turtles dwelling out of the ocean have hands with fingers and toes with nails. Males have longer nails to tickle the necks of females they are courting.
I was motivated to write about sea and freshwater turtles today due to an exchange on a Facebook post. The group discusses items found on Sanibel, which used to be one of my favorite islands. Unfortunately, people discovered the island’s beauty and the resulting development has driven out most of the wildlife I enjoyed. I worked in the J.N. Ding Darling National Wildlife Refuge for a couple of summers when the offices were by the historic lighthouse. Unfortunately, Hurricane Ian removed those buildings and severely damaged the lighthouse.
Misunderstandings About Turtles
The controversial posting asked for the identification of a hatchling turtle in a man’s hand. The photo included in this blog is the same type that was being queried. A few people identified the turtle as a diamondback terrapin (Malaclemys terrapin), a freshwater species that can also live in brackish water. Unfortunately, many people suggested throwing the terrapin back into the ocean. But it didn’t come from the ocean. Terrapins are not sea turtles. Freshwater turtles can’t survive in high salt water concentrations, like oceans.
Sadly, this isn’t the first time I’ve seen this misunderstanding. In the first book of my Don’t series, Don’t Call Me Turtle, I tell people not to throw tortoises in the ocean or lakes – it will kill them. Later, I was asked to write a book about the differences between the freshwater and sea turtles on the Cayman Islands. They, too, have a problem with mistaking freshwater turtles for sea turtles and thinking they are helping by throwing the unfortunate reptiles into the ocean. I was asked to write the book Hickatees Vs. Sea Turtles.
Apparently, this problem still needs addressing if people are saying to toss freshwater turtles in the Gulf of Mexico off Florida. Sigh. My educational work is not done.
I don’t know what happened to the baby turtle pictured on Facebook. Was it picked up merely for the photo, or was it a captive-bred hatchling for the pet trade? I suspect it was picked up and then released. I was delighted to see such a good-looking turtle on Sanibel. Maybe there is a bit of habitat left for them.
The Plight of Turtles on Sanibel
Sanibel has lost many of the reptiles that used to live there. I hate to see more species driven from the island.
Fifteen species of turtles have been found on Sanibel, including five sea turtles that use the beaches for nesting.
In addition, there is one species of tortoise! The gopher tortoise, Gopherus polyphemus, can be found in the upland areas. But I have to wonder how many survived the sea surge from Hurricane Ian. A survey found that some were lost along the coastline, but others farther inland did survive. I hope there is enough suitable ground for them to continue to thrive.
Other turtles found on Sanibel:
Florida softshell, Apalone ferox
Florida snapping turtle, Chelydra serpentina
Red-eared slider, Trachemys scripta elegans (this is part of the red-eared natural range. This species has become invasive in many parts of the world.)
Yellow-bellied slider, Trachemys scripta scripta
Florida mud turtle, Kinosternon steindachneri
Striped mud turtle, Kinosternon baurii
Box turtle, Terrapene bauri
The sand beaches of Sanibel provide nesting habitat for several sea turtles:
Green, Chelonia mydas
Loggerhead, Caretta caretta (I tagged a loggerhead on Sanibel. I hope #1295 is still going strong.)
Kemp’s Ridley, Lepidochelys kempii
Leatherback, Dermochelys coriacea
Hawksbill, Eretmochelys imbricata (I swam with a delightful hawksbill in St. Thomas.)
