Despite its name, the green sea turtle’s (Chelonia mydas) shell is usually brown, olive, or gray. At 0.9 to 1.2 meters (three to four feet) long, it’s the world’s largest hard-shelled sea turtle, weighing over 136 kilograms (300 pounds). It is also unique among turtles for being an herbivore. In fact, the green sea turtle’s diet of seagrasses and algae gives its fat a greenish color—and explains its name. Like gardeners of the sea, turtles keep seagrass beds healthy by “mowing” the seagrass and recycling nutrients. This helps many other ocean animals who use seagrass beds and coral reefs as nurseries for their young.

Green sea turtles have been overhunted around the world for their meat, eggs, and shells. Protection has helped turtles recover in several places, including Mexico, the Seychelles, and Florida in the United States. However, many green sea turtles still face illegal hunting, fishing gear that traps them, and the loss of habitat to human activities and climate change. Green sea turtles nest in over 80 countries and swim through the waters of more than 140 countries. This is why global cooperation is key to the survival of these ancient marine creatures.