By Alison M. Brown
Sea turtles have been swimming in the oceans for over 100 million years and even survived the dinosaur extinction. If you’ve ever gone snorkeling or diving in a tropical region, you’ve probably seen one. You can spot them either in the open ocean, or most commonly, in coastal habitats.
Seven species of sea turtles exist today, which include the leatherback, green, loggerhead, flatback hawksbill, kemp’s ridley, and olive ridley. Sea turtles are reptiles that require oxygen to survive, which is why you can sometimes spot them on the ocean surface. However, they have very powerful lungs and can hold their breath for 4-7 hours at a time. Their diets mostly consist of small crabs, mollusks, or other crustaceans, except for the leatherback turtle that eats mostly jellyfish and the green turtle that feasts on seagrass. The green turtle helps control seagrass growth, but all species support ocean ecosystem health by regulating the population sizes of the creatures they eat.
The largest sea turtles are the leatherback, who can grow up to 63 inches in length. Most species of sea turtles are currently considered “vulnerable” or “endangered” when it comes to extinction, with hawksbill and kemp’s ridley turtles falling in the “critically endangered” category. According to the World Wildlife Foundation (WWF), species are considered “critically endangered” when a species is "facing an extremely high risk of extinction in the wild.”
Some of the daily threats sea turtles face include illegal fishing and trading, habitat disruption, accidental bycatch, predatory hunting, and climate change. They are also harmed by boat propeller accidents, or are sometimes involved in fishnet-related drownings. In the last 30 years, the leatherback turtle’s population has decreased by as much as 90% in the Eastern Pacific due to a combination of these risks.
In addition to these dangers in the water, sea turtles also face threats on land. Most sea turtles nest on beaches, meaning they need to travel from the ocean up to a comfortable sandy area, which puts them in a more vulnerable position. Once a nesting area has been found, females dig a pit in the sand and usually lay 100 to 200 eggs which take about two months to hatch. The most dangerous time in a turtle’s life is when it travels from the nest to the sea. Predators such as crabs and seagulls are usually the culprit of many hatchling deaths, which is why so many eggs are laid each time. Even when hatchlings reach the sea successfully, they are still vulnerable to predatory attacks from sharks and other large fish. In fact, according to the Sea Turtle Conservancy, only 1 in 1,000 sea turtles survive to adulthood.
So how does a sea turtle protect itself from all of these threats? Luckily most turtles have a hard shell that helps protect them from predators. One of the main differences between sea turtles and other types of turtles is that sea turtles can’t pull their limbs into their shells like other species can. Sea turtle shells are mostly made of bone and cartilage which are covered with thin plates called ‘scutes.’ Leatherback turtles actually have a soft shell made up of thick leathery skin, but because of their large size, are only threatened by big predators - and humans.
Another self-protection mechanism sea turtles have is their excellent swimming abilities. Sea turtles can swim quite fast reaching an average of 15 miles per hour. Their quick swimming abilities enable them to out-swim a lot of their predators in order to find safety or blend-in with a nearby rock. Some of those predators include orcas and sharks, who have strong jaws and are able to penetrate their hard shells.
But because turtles are also flat, they are able to swim horizontally, thus creating a surface area that’s too big for the jaw of a shark. What usually happens, is the shark winds up pushing the turtle’s shell forward with the tip of its nose, or trying to bite one of its limbs. Unfortunately this protection technique is only successful if the turtle spots the shark beforehand and is able to situate its body in the right position.
While sea turtles don’t have a ton of self-protection methods, it’s important that we continue to support laws that keep them safe from human consumption or harm. With threats such as climate change, turtles and other marine life need as much support as they can get. If you’re feeling generous, the World Wildlife Foundation has created the option to adopt a sea turtle through their website. The adoptions vary in price, but all kits come with a photo, adoption certificate, and a species information card.
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