Characteristics

There are a number of outward differences between the green sea turtle (Chelonia mydas) and the black sea turtle (Chelonia agassizii). Its deeper coloring is one of its most striking characteristics. The brighter, more diverse coloring exhibited in green sea turtles stands in stark contrast to the carapace of adult black sea turtles, which may be anywhere from dark grey to black. The turtle gets its name from the fact that its black coloring is present all over its body, not just on its carapace.

When compared to green sea turtles, black sea turtles tend to be on the smaller side. The average length of the carapace of an adult black sea turtle is 70–100 cm, or 28–39 inches. They may be anything from 154 to 265 pounds (70 to 120 kg). This size disparity is a result of an adaptation that allows them to thrive in their coastal and nearshore habitats, where they eat mostly on seagrass and algae.

In contrast to green sea turtles, black sea turtles have a more dome-shaped and less flattened carapace, or top shell. They adapt to their rocky reef and coastal environments by taking on this dome-shaped body, which may improve hydrodynamic efficiency, making them more maneuverable and easier to swim for. The carapace is composed of bony exterior plates, or massive, non-overlapping scutes, that provide support and protection.

The flippers are another telltale sign of a turtle. Their large, paddle-like front flippers are an adaptation that helps them swim great distances in the open sea and find their way around coastal areas. The Black Sea Turtle is able to swim and hunt with ease because of its strong and sturdy flippers. Shorter and more rounded, the back flippers aid in steering and moving.

Black sea turtles are herbivores, therefore their little heads, pointed snouts, and powerful jaws are an adaptation to their food. Their primary food sources are algae and seagrass, both of which need a powerful bite for efficient grazing. Serrated edges line the inside of their mouths, allowing them to efficiently rip foliage for food.

The appearance of adult Black Sea Turtles differs from that of juveniles. The hatchlings' coloring is usually deeper, and the white or pale marks on their carapace and flippers are more noticeable. As they get older, these patterns disappear. Also, the carapace is more circular while the organism is young, but it becomes longer and more dome-shaped as it matures.