Day 265#: Hickatee
Today's animal of the day is the Hickatee (Dermatemys mawii)!
Photo credit: Matěj Baťha
Also known as tortuga blanca in Spanish, which means "white turtle", the hickatee is a species of freshwater turtle that can be found in Belize, Guatemala, southern Mexico, and possibly Honduras. These charming little oddballs are the only living member of the family Dermatemydidae, which likely split off from other turtles sometime during the Mesozoic era, since the closest known relatives to this family all went extinct during either the Jurassic or Cretaceous period. They are a relatively large turtle, with the largest specimens ever recorded having a 24-inch-long carapace (the top part of their shell) and being estimated to weigh around 49 pounds! However, those estimates all come from long-dead specimens, and modern-day hickatees usually range between 24 and 31 pounds. They are usually either a blackish-brown or very dark olive green color, and adult males have yellow/cream-colored facial markings, which the females lack.
Photo credit: Milena Mendez
Hickatees are primarily nocturnal and almost entirely aquatic; the only time they ever leave the water is to lay their eggs. They won't even come on land to sunbathe as many other river turtles do. Speaking of their eggs, these turtles are unique in the reptile world since they are one of the only types of eggs that can be submerged completely underwater for several days and still hatch perfectly fine! This is probably because these turtles often bury their eggs in places that get a lot of flooding, so their eggs need to be able to survive being submerged until the floodwater recedes. In fact, scientists used to believe that hickatees actually laid their eggs under the water; however, these observations were likely a result of the scientists finding nests that were submerged by the aforementioned flooding.
Photo credit: Heather Barrett
Their diet consists of a variety of aquatic vegetation, such as river grass, but they'll also eat fruit, leaves, and flowers if they are growing close enough to the river that they can reach them from the water, or if they happen to fall into the water. Most herbivorous reptiles need to sunbathe in order to speed up their digestion, since leaves don't really provide a lot of energy, so they need to eat a decent amount in order to survive. But, as I mentioned before, hickatees don't bask like other turtles do! Instead, it's believed that these turtles must have some sort of symbiotic relationship with the organisms that live in their gut, where the organisms help break down the vegetation to make it easier for the turtles to digest, and in return, they get to live safely in their stomachs and also get to eat whatever the turtles eat.
Photo credit: Sean Werle
At the moment, this is just a theory, but scientists did a study where they raised two captive clutches of these turtles and provided one clutch with poop from adult turtles, which is commonly eaten by hatchlings in the wild, but didn't provide it to the second clutch. The clutch that was allowed to eat the poop grew at a much faster rate than the clutch without this "food additive", so it's likely that whatever beneficial organisms help the turtles digest are passed on from parents to offspring via their poop. It's also possible that a special type of nematode, which is commonly found in large numbers inside these turtles' intestines, may help them digest their food since a very similar species is also found inside the guts of iguanas, which has been proven to help them digest plant matter more effectively.
Photo credit: Valentina Sandoval Granillo
Juvenile turtles and unhatched eggs are often preyed upon by a wide variety of predators, such as raccoons, snakes, coatis, and various species of birds. Fully grown adults are large enough that they have fewer predators, but they aren't totally safe. American and Morelet's crocodiles will often feed on hickatees by crushing their shells with their jaws and swallowing them whole! Jaguars have also been observed occasionally catching them and cracking open their shells to scoop out their soft innards. Neotropical otters also hunt these turtles, and will usually gang up on them and bite their heads, tails, and limbs off to allow access to the insides of their shells, which they leave intact. However, the most common predator for adult hickatees is actually Homo sapiens, aka humans.
Photo credit: Cayman Islands Department of Environment
These turtles were very culturally significant to the ancient Mayans and numerous other indigenous groups that lived/live in Central America. They were often eaten in ceremonial feasts, and their shells were used in everything from decorations to shields and even musical instruments. There's actually fossil and genetic evidence that suggests that the Mayans may have actually hunted the local hickatee population to extinction in their areas, but they were eventually replaced by a new migrant population sometime afterwards. Sadly, the same thing is happening to this species in the present, but on a much larger scale.
Photo credit: Melvin Mérida
Thanks to overhunting and human activities polluting many of the rivers that these turtles call home, the hickatee is now considered a critically endangered species and is at serious risk of going extinct. Because turtles are considered "fish" by the Catholic church, a lot of people consume them for Lent, but also during other parts of the year. Apparently, their meat actually turns white after you cook it, which is why they're called "tortuga blanca". There are a handful of farms that raise these turtles in large numbers, not for conservation but to be raised for slaughter. In theory, this does help reduce the amount of wild turtles being killed, but these farmed hickatees are often kept in very poor conditions, which increases the likelihood of someone getting a disease from eating one of these farmed turtles. So, a lot of people are still just going out into the wild and hunting them. Personally, I think we should just resist the urge to eat an endangered species. Luckily, in many of the places where these turtles are found, there are laws preventing the harvesting of these turtles in the wild, and this seems to have helped certain populations bounce back, though the species as a whole is still on the decline, especially in areas closer to human habitations.
