Friday, March 9, 2012

A closer look at the hybrid sea turtle, "Eclipse"

At first glance, Eclipse appears to be just another feisty sea turtle in our hospital, splashing around his tank and rubbing his shell on his PVC backscratcher. But Eclipse is very unique, and you’ve likely never seen another turtle that looks just like him.

That’s because Eclipse is a rare hybrid, and he possesses an interesting combination of physical traits inherited from his parents. Although genetic analysis is still pending, it’s very apparent that this juvenile is a cross between a loggerhead and a green sea turtle. If you know even a little about the very different life histories of those two species, you’ll be apt to spend as much time as I have pondering the many choices this charismatic little turtle is going to have to make in the future!

The shape of a turtle’s head and beak are indicative of its diet. For example, the loggerhead turtle is known for its large, wide head and massive beak. This combination of a robust beak, which contains cutting and crushing plates, and a large skull, which houses a mass of muscle, enable the loggerhead to easily crush the shells of crabs and mollusks. On the opposite side of the spectrum is the green sea turtle, who is equipped with a small head and beak with a serrated edge. This serrated beak is perfect for tearing and consuming sea grass and algae, staples of the greens’ diet.

Take a look at Eclipse’s head and beak in the picture below. Like a green, his head is small and he has only two scutes (or scales) between the eyes. However, his coloration and beak, which lacks a serrated edge, closely resemble a loggerhead’s. Will he have enough muscle strength in his small skull to eat crabs? Or will he be able to consume sea grass efficiently without a serrated beak?

Sea turtles are often identified in part based on the number of scutes (individual scales or sections) on their carapace (shell). In this aspect, Eclipse also appears to be half green turtle and half loggerhead. On his left side, Eclipse has just four scutes like a green. However, his right side has five scutes, just like a loggerhead. The shape and coloration of his shell more closely resemble a loggerhead’s as well, as he lacks the beautiful marbleized patterns and rounder shape characteristic of green sea turtles.

Regardless of his genetic heritage, Eclipse is thriving in our hospital and has almost fully recovered from being cold-stunned in Massachusetts last November, first receiving treatment at the New England Aquarium. Although he’s not a fan of the romaine lettuce we offer him, a treat which green turtles love to munch on, he chows down on a healthy assortment of restaurant quality fishes like smelt, mackerel, and capelin. Come visit Eclipse in our hospital and learn more about what makes him unique!

Christi Hughes
Sea Turtle Biologist