Ocean – Discover-Nature

Sea turtles live in every ocean environment around the world, nesting on tropical and subtropical beaches, and migrating long distances. They spend their entire lives at sea except when females come ashore to lay their eggs. They have been on earth for over 100 million years, surviving the period when most dinosaurs and other reptiles died out 65 million years ago.

^{Coral reef & hawksbill sea turtle by jakubgojda, Indian Ocean, Maldives}

Sea turtles are large, air-breathing reptiles with upper (carapace) and lower (plastron) shells. Six of the seven species are covered by hard scales called scutes. Although none have teeth, jaws are suited to each species specific diet. Sea turtles do not have ears, but there are eardrum openings covered by a flap of skin. Their sense of smell is excellent as is their underwater vision, although they are nearsighted when out of the water. Along with a streamlined body, they possess powerful legs and claws for swimming, diving, and catching food.

^{Green turtle eating seagrass by LauraDin, Getty Images}

^{Green sea turtles, Chelonia mydas, on coral reef by Artush, Alam, Egypt}

Sea turtles, along with manatees, are excellent caretakers of seagrass beds and coral reefs, habitats that are vital to the reproduction of fish, shellfish, and crustaceans. Seagrass, one of their favorite foods, grows faster and stronger with daily trimming from turtle munching. Coral beds, vulnerable to collapse and suffocation under mass quantities of sponges and small crustaceans, benefit from sea turtles that eat several hundred of these animals each day.

^{Olive ridley digging egg chamber by JHVEPhoto, Getty Images, Costa Rica}

^{Green sea turtle hatchlings by Penny Britt, Getty Images}

After reaching sexual maturity, which takes from 15 to 50 years, depending on the species, female sea turtles return every two to five years to the beach where they were born to lay their eggs. On average, they dig three to seven nests and place about 100 eggs in each. Baby sea turtles break out of their egg and instinctively flee for the lighter colored horizon where the ocean meets the beach. They spend several years in the open ocean feeding and growing before venturing into shallower waters to eat, mate, and reproduce. Only about one in a thousand babies will grow to be an adult. Most are prey for birds, crabs and fish, but many are killed by humans for food, medicines, and religious ceremonies. Nesting site habitat destruction and turtles caught as part of the fishing industry also play a part in population decline.

^{Jellyfish & jacks by melissaf84, Getty Images, Coral Sea; Whelks by Pack-Shot, Getty Images; Reef crab by JohnAndersonPhoto, Getty Images, Lembeh Strait, Indonesia; Posidonia seagrass meadow by Arnaud Abadie, Getty Images Signature, Mediterranean Sea}

Females lay all of their eggs on land, but nesting sites and the best feeding sites may be thousands of miles apart. Sea turtles are found throughout the world’s oceans following concentrations of jellyfish, sponges, and crustaceans found in coral reefs and seagrass beds. Leatherback females have been tracked making migrations of over 12,000 miles between nest sites and the best annual feeding grounds during non-breeding seasons.

Read facts on each species in the sidebar, shown below. Come to the Jurica-Suchy Nature Museum where we have loggerhead, hawksbill, and green sea turtles on display to learn more about these creatures and their hidden realms.

^{Pics 1&2: Green sea turtle, Chelonia mydas, by DonArnold, JSNM 2023; Pics 3-6: Hawksbill sea turtle, Eretmochelys imbricata, by DonArnold, JSNM 2023; Pic 7: Loggerhead sea turtle, Caretta caretta, by DonArnold, JSNM 2023}

Sea turtle species…

There are seven species of sea turtles in the world. All are experiencing dwindling populations from various threats. Two are critically endangered: the hawksbill sea turtle and the Kemp’s ridley sea turtle. Two are endangered: the green sea turtle and the flatback sea turtle. Three are listed as threatened: the leatherback sea turtle, the olive ridley sea turtle, and the loggerhead sea turtle.

Hawksbill sea turtles, Eretmochelys imbricata, have a narrow head allowing access to tight spaces in coral reefs, the usual spot to find sponges. They consume 1,000 pounds of sponges annually, keeping coral reefs free from suffocation by the sponges. These turtles are medium size at 2′-3′ and 100-200 pounds. Females nest on beaches among rocky areas 3-4 times in a season and lay 140-200 eggs in each nest.

^{Hawksbill portrait, Eretmochelys imbricata, by Sheraca, Dec 2014; Hawksbill sea turtle, Eretmochelys imbricata, by Goug Finney, Sep 2019}

Kemp’s ridley sea turtles, Lepidochelys kempii, are the smallest species at 2′ in diameter and 75-100 pounds. Kemp’s ridley turtles have made a huge recovery from the 1960s, when there were about 200 individuals left, to almost 9,000 today. This is due to changes in Mexico’s laws, where 95% of their nesting takes place, to protect nest sites from disturbance.

^{Kemp’s ridley sea turtle, Lepidochelys kempii, by USFWS, Sep 2010}

Green sea turtles, Chelonia mydas, grow to 4′ and 500 pounds. They are herbivores with a finely serrated beak for biting seagrass and scraping algae from hard surfaces. This is the only species known to come onshore to bask in the sun. They are named for the color of their fat, not their shell.

^{Green sea turtle, Chelonia mydas, by Florida Fish&Wildlife}

Flatback sea turtles, Natator depressus, have a flattened carapace, unlike other turtles. They are medium sized at 3′ and 200 pounds. Found only in Australia, they do not migrate. Females lay only about 50 eggs in a nest, but nests are well spread out, helping to better protect their eggs. Their biggest threat is being preyed upon by saltwater crocodiles.

Leatherback sea turtles, Dermochelys coriacea, are the largest species at 4′-8′ and 500-2,000 pounds. They consume mostly jellyfish, daily eating their own weight in food. They have no scutes, but are covered by a flexible, leathery skin that allows them to dive up to 4,000 feet deep searching for prey. These turtles have thermoregulatory adaptations that allow them to hunt in very cold waters from Alaska to Chile, and they regularly make the longest migration of any vertebrate animal, traveling over 12,000 miles annually.

^{Leatherback sea turtle, Dermochelys coriacea, by Claudia Lombard, USFWS, Jun 2011}

Olive ridley sea turtles, Lepidochelys olivacea, are small at 2′ and 75-100 pounds. They are the most abundant of all species. On certain beach sites, nesting females form an arribada, a grouping of all the females offshore who all come ashore at the same time to nest and lay eggs. Females on other sites may nest alone. Arribadas are particularly vulnerable to mass mortality events, but these are rare and population numbers remain consistent.

^{Olive ridley sea turtle, Lepidochelys olivacea, by Charles Peterson, Head Start Programs, Oct 2002}

Loggerhead sea turtles, Caretta caretta, grow to 4′ and 200-400 pounds. Their very large heads and jaws can easily crush hard shells, allowing them to eat crabs, conches, and whelks. They have the largest concentration of nests annually, including 30,000 at a single Mediterranean location. Their shells provide space for 50 to 100 epibionts: plants and invertebrates that live permanently attached to their shells.

^{Loggerhead sea turtle, Caretta caretta, & epibionts by actor212, Aug 2017}

Puffins are part of the Alcidae family of seabirds along with murres, guillemots, auklets, murrelets, and 25 recently extinct species. All members of the family can fly and are excellent divers and swimmers. Three species are found in the North Pacific Ocean including the tufted puffin, Fratercula cirrhata, horned puffin, Fratercula corniculata, and rhinoceros auklet, cerorhinca monocerata. The Atlantic puffin, Fratercula arctica, is the only species found in the North Atlantic Ocean.

^{Images clockwise: Atlantic puffin, Fratercula arctica, portrait by stockomotion, Getty Images Signature; Horned puffin, Fratercula corniculata, showing horns over eye by webguzs, Getty Images; Tufted puffin, Fratercula cirrhata, on the water by Bruce Block, Getty Images Signature; Rhinoceros auklet, Cerorhinca monocerata, by nikkigensert, Getty Images}

The rhinoceros auklet was thought to have been misidentified when it was first discovered and named. However, DNA testing has shown that all four puffin species have a common auklet ancestor. Puffin species have short, stocky wings and tails, with darker gray-to-black plumage on top of their heads and backs and lighter whitish-to-brown plumage on their faces and underparts. Their bills change color during breeding seasons to display several stripes of red, orange, yellow, and black.

Tufted puffin, *Fratercula cirrhata*, breeding coloration by MrDaz, Getty Images Signature

Short wings require the birds to beat them quite fast to fly, about 400 beats a minute, but they achieve speeds of 45 to 55 mph in flight. Short wings are used as powerful flippers underwater along with feet used as rudders. Puffins can dive to 200 feet or more catching a dozen or more small fish and invertebrates as they swim through the water. A uniquely designed hinge on their bill allows the top and bottom bill to meet at several different angles so the bird can add more fish without losing its grip on any that are already caught.

^{Images clockwise: Horned puffin, Fratercula corniculata, with fish catch in Alaska by Gerald Corsi, Getty Images; Atlantic puffin, Fratercula arctica, with catch by Daniel Jara, Getty Images; Rhinoceros auklet, Cerorhinca monocerata, with seven fish Andrew Reding, Jul 2010}

Puffins spend winters at sea, far from land, floating on the surface or pursuing prey. Breeding season occurs in late spring, and most adult birds come together, forming large colonies containing breeding and non-breeding individuals. Non-breeding birds spend hours each day exhibiting a behavior called wheeling flight – flying figure eights over the cliffs where the colony is located. After finding a mate, puffins form long-term pair bonds. After breeding, pairs may split up when out at sea, but often return the next breeding season to find the same mate and nesting site. Puffins breed in large colonies on coastal cliffs of offshore islands. Only one egg is laid and both parents incubate the egg and feed the chick. Chicks fledge at night, and juveniles spend the first five years out at sea before returning to the breeding colonies.

^{Horned puffin, Fratercula corniculata, nesting on Latrabjarg Cape, Vestfirdir, Iceland by Nikolay Tsuguliev, Getty Images}

^{Atlantic puffin roost by Shankar S., May 2016}

Puffins are not considered endangered, but are starting to encounter trends affecting the continuity of their successful breeding. Warming waters in the oceans are reducing populations of fish that breed and live in cold water areas, that are the favorite prey of the auk family. Threats on the mainland of Iceland, historically one of the largest breeding colonies, include being hunted by mink introduced in the 1930s, so most colonies are now located on offshore islands. Hunting for feathers, eggs, and meat has been sustainable on island ranges for hundreds of years. However, hunting on the American mainland during the late 1800s and early 1900s eradicated the population at one point. In the last 50 years, about 50,000 birds have returned to protected areas in Maine. Their biggest natural predator is the great black-backed gull which dive-bombs and picks off birds near shore during breeding periods.

^{Tufted puffin, Fratercula cirrhata, spreading its wings by TiannaChantal, Getty Images}

Puffins have an average lifespan of over thirty years, spending most of their lives out at sea. Reproduction rates are low with only one chick born each year to a pair of puffins, but a breeding pair may produce twenty chicks in their lifetimes and threats from natural predators are small. Puffins are favorite species in many zoos and some aquariums. Learn more by visiting a local institution or take a virtual tour from a live webcam at: https://explore.org/livecams/puffins/puffin-loafing-ledge-cam.

Tag: Ocean

Sea Turtles

Puffins