At the Georgia Sea Turtle Center, staff field a variety of questions on a regular basis.
Commonly, educators, tour guides and researchers hear questions such as “Do turtles breath underwater?” and “When is nesting season?” Here, we’re rounded up some of the most frequently asked questions in an effort to answer those common queries.
For even more turtle answers, be sure to visit the Georgia Sea Turtle Center, and stay tuned to our Facebook page, here.
Q: Which sea turtle species nest on the Georgia coast?
A: Georgia’s most common nester is the loggerhead sea turtle (Caretta caretta). Occasionally, leatherbacks (Dermochelys coriacea) will nest in Georgia as they migrate north, and green (Chelonia mydas) sea turtles have also nested here (first recorded on
Jekyll in 1989).
Q: Which species of sea turtles pass through the Georgia coast?
A: In addition to the loggerhead, the leatherback, green, Kemp’s Ridley (Lepidochelys kempii) and Hawksbill (Eretmochelys imbricata) sea turtles may be found in Georgia waters.
Q: When is nesting season for loggerheads?
A: In the United States, nesting season ranges from early May to late August. Hatchlings begin emerging in mid to early July and will continue through October.
Q: Why are the nesting numbers periodically so low, like in 2007, for example?
A: It is difficult to say for sure. Loggerhead sea turtles are cyclic nesters and nest every 2-3 years. Therefore, nesting totals undergo periodic fluctuations from year to year. For example, a turtle that nested in 2009 may not nest again until 2011 or 2012. In addition, an environmental or anthropogenic disturbance that occurred many years ago may have resulted in reduced survivorship, which can then become evident during years with low nest totals.
Q: What is the best time of night to see a nesting sea turtle or emerging hatchlings? Do they tend to come out at high tide? what about during a full moon?
A: It is difficult to predict when and where you can spot a sea turtle, since they generally nest and hatch any time between sunset and sunrise. Some research shows that nesting density increases during a full and new moon, when the tides are at their highest, thus allowing the turtles to exert less energy crawling on land to find an appropriate nesting site. Hatchlings emerge from their egg chambers, located 2 to3 feet underneath the sand, only after their incubation period is complete (this range varies between species). They use temperature cues to determine the appropriate time for emergence (i.e. cooler temperatures=nighttime). We encourage participation in our organized Turtle Walks (2x per night, June 1-Mid August).
Q: How can you tell if a turtle has been on the beach?
A: The visiting turtle will leave a tractor-trailer like track in the sand. Indications of a nest include thrown sand and/or vegetation, a body pit and an adjacent mound of tossed sand used to camouflage the exact location of the egg chamber.
Q: Why do sea turtles cry when they are laying their eggs?
A: Actually, all sea turtles “cry,” not just nesting females. In fact, it is not really crying but rather an evolutionary adaptation sea turtles have gained rid their bodies of excess salt. The salt glands are located behind the turtles’ eyes and are actually bigger than the turtle’s brain!
Q: When are nests relocated by the turtle patrols?
A: Nests are relocated sparingly throughout Georgia. However, nests are moved if they are too far below the high tide line, along the rock wall, or in a particularly poor habitat. These nests would be washed over too frequently and would not survive. It is important to manipulate or interfere with sea turtle nests as little as possible, as it can cause a decrease in hatching success rate, affect the sex ratios or alter hatchling fitness.
Q: How often will one female nest in one summer?
A: A female loggerhead will nest on average between 4-6 times in one season. The internesting interval is approximately 14 days. She will not return to nest again for 1-3 years.
Q: How long is the incubation period for a sea turtle?
A: This will vary by species. On average, a loggerhead nest will hatch after 45-60 days of incubating. Whereas a leatherback nest will incubate for 70-90 days! Coincidentally, nest temperature is inversely related to the length of incubation.
Q: What happens if a turtle cannot find a suitable place to nest?
A: If a turtle cannot nest, she may simply return to the ocean without laying her eggs at that time. This is referred to as a false crawl or non-nesting emergence. If after several attempts, she is still unsuccessful, she may release her eggs into the ocean or resorb them internally. Statistically, turtles may false crawl about 50% of the time.
Q: What does an egg chamber look like?
A: A sea turtle egg chamber resembles and upside-down light bulb; narrow at the top (~8-10in. in diameter) and gradually widening at the bottom to the size of a basketball or volleyball. For a loggerhead, it is typically about 2 feet deep and camouflaged by the nesting female. Sea turtles do not care for their young. After camouflaging the egg chamber, the female returns to the sea, never to return to that nest.
Q: How many hatchlings will survive to maturity?
A: Out of all the sea turtle eggs laid, about 75% will hatch. Of that 75%, recent research estimates that only 1 out of every 4000 will make it to adulthood.
Q: How can one tell if a turtle is a male or female?
A: There are no external differences between male and female sea turtles until they reach adult size (~30-35yrs), which is based on the measurements of the carapace and 44 will vary between species. Once they have reached adult size however, the male’s tail will grow very long and stick out far beyond its carapace, whereas the female’s tail will stay short and tucked under the carapace.
Q: What determines the sex of a sea turtle?
A: The sex of a sea turtle is determined during the incubation period, specifically the middle-third (20-40 days), as reptiles are not believed to have sex chromosomes. At 29.6C, there is a 50-50 ratio of males to females. Warmer temperatures will produce females, while cooler temperatures tend to produce males. (This is opposite from alligators!)
Q: How do sea turtles hatchlings find the ocean?
A: Hatchlings use light and shadow cues on the beach upon emerging from their egg chambers to locate the ocean. They orient away from shadows, produced by dunes and vegetation on the west side of a natural beach, towards the brightest horizon, which should naturally be over the ocean (reflecting the moon and stars, sunrise).
Q: Upon maturity, do sea turtles return to the same location they hatched from?
A: Yes! Research has shown that sea turtles do have natal homing and seem to return to the same region/area to nest–within 5-30 miles of where they themselves hatched. This is why it is important to allow hatchlings to use their natural instincts to crawl out of their egg chambers, find and crawl to the ocean on their own.
Q: When do sea turtles reach reproductive maturity?
A: This varies with species, but for loggerheads the current research says approximately 34 years of age. Some factors associated with a turtle reaching reproductive maturity include the habitat, food source availability, genetics and overall health of the animal.
Q: When is mating season? how does the female have multiple clutches?
A: Mating season for loggerheads takes place in April and early May prior to nesting season. The female will likely mate with several males and store the sperm in her oviduct. She is able to release the sperm and fertilize the eggs throughout the season. This means that the eggs in one nest will not necessarily share the same father.
Q: What about the male sea turtles? Do they ever return to land?
A: No. After leaving the beach as hatchlings, male sea turtles spend their entire life in the ocean. It is very laborious for the turtles to move on land, so only the females will return to land to nest with the sole purpose of laying a nest. As adults, males are generally only found on land if they are sick or injured. There is, however, one population of Green Sea Turtle in Hawaii, where males will crawl onto shore to bask.
Q: How long do sea turtles live?
A: No one is absolutely sure how long sea turtles live. Since they are solitary, migratory animals (only congregating on nesting grounds), they are difficult to study. Most of the information we have is based on the nesting females and hatchlings, although more research is being conducted than ever offshore. Our best estimates on life spans for sea turtles are based on captive animals. However, it is difficult to determine if those estimates are transferable to a wild population. We do have a nesting female from Jekyll Island that we know to be at least 60 years old, based on a mother-daughter nesting pair DNA match.
Q: What are the “lost years?”
A: Until recently, scientists did not know where the young turtles went after they left the nest. There was a mysterious gap from the time when they first entered the ocean, until they reappeared as juveniles (‘dinner plate’ size). This period was referred to as the “lost years.”
However, biologists now believe that these years are spent in the open ocean (where there are fewer predators). After entering the ocean (known as their ‘swim frenzy’), they swim towards the Gulf Stream where they will find a mat of Sargassum. that they will use for camouflage and as a food source. They are believed to ride the currents for a few years returning to inshore waters when they approximately ‘dinner plate’ sized. How long it takes a turtle to grow to this size will vary between species and is dependent upon a number of factors including food availability, habitat health, parasites/sickness, injury and genetics.
Q: How do sea turtles breathe? How often do they need air?
A: Sea turtles have lungs and need to breathe air—they do not have gills. They breathe frequently, every few minutes when actively foraging and can hold their breath for about 30 minutes on average. During times of rest, however, they can remain underwater for hours at a time.
Q: How long can a sea turtle hold its breathe?
A: Anywhere from a few seconds to a few hours. It depends mainly on two things: how active they are and how big they are. The turtle’s lungs line the entire length of the carapace (they have their own scuba tanks) so the bigger the turtle the bigger the lungs and the longer he can stay down. If a turtle is sleeping they aren’t using up as much oxygen so they can stay down longer, whereas a very active, foraging turtle will have to surface a lot more frequently. In captivity, it’s an average of about 5 minutes. In the wild, it’s an average of 30 minutes.
Q: Can turtles ever leave their shells?
A: No. Unlike many freshwater turtles a sea turtles cannot retract into its shell, and no turtle can it leave its shell.
Q: How does the weather affect sea turtle nesting or hatching? (i.e. storms?)
A: Sea turtles will nest and hatch in most weather conditions—rain or shine. However, heavy rain and storms can cause high tides to wash over the nest. Too much water can cause eggs to stop developing or drown hatchlings. Hurricanes and tropical storms can impact the nest by eroding the dunes and washing the nests into the ocean.
Q: Do lights affect sea turtles? How?
A: Artificial lights on and directed towards the beach can have major impacts on sea turtles, both nesting females and hatchlings. Bright lights can deter a female from nesting, cause her to false crawl, or disorient her before or after nesting. They are even
more problematic for hatchlings that use light and shadow cues to orient towards the ocean; they can see a light from a ¼ mile away and head towards it! Bright, white lights easily confuse and disorient sea turtle hatchlings in the wrong direction and away from the ocean making them more susceptible to predators, dehydration and exhaustion, and in some cases/areas into storm drains, pools, backyards or roads where they are often run over by cars.
Q: What is ‘turtle-friendly’ lighting? How can i make my lights ‘turtle- friendly’?
A: ‘Turtle-friendly’ lights are lights that have been shown not interfere negatively with nesting sea turtles or emerging hatchling sea turtles. Lights that are bright or emit white or short wavelengths are NOT turtle-friendly. Lights with long wavelength bulbs (i.e. pure red filters or amber bulbs) or even monochromatic bulbs such as Low Pressure Sodium (LPS) ARE turtle-friendly. Other options for making your lights ‘turtle-friendly’ are to:
- Low wattages or lumens are better—use only the minimum wattage needed.
- Lower the height of the fixture to the minimum height needed. Often this will allow the dune and beach vegetation to obscure the light from the beach.
- Re-direct your fixture away from the beach so it is not shining directly on or towards the beach
- Shield your fixture on the beach side (extending to the north and south as well),often this will shine the light where you want and/or need it, rather than it being wasted to the atmosphere.
Q: Why is it important for coastal bridge lighting to be ‘turtle-friendly’?
A: Even lights from a distance can negatively affect sea turtles, as city lights produce abright sky glow that can mis-orient turtles. For example, at Kennedy Space Center in Florida, NASA changed the lighting at their launch pads so that sea turtle hatchlings on nearby beaches would not be confused!
Q: What predators do hatchling sea turtles have? Adults?
A: Hatchlings and developing turtles face predation from a variety of animals including feral hogs, raccoons, shorebirds, ghost crabs, fire ants, predatory fish and humans. As a turtle gets older, bigger and its shell gets harder, it becomes less vulnerable to predators.Natural predators of adult sea turtles include some sharks, namely the tiger shark. Humans however pose the most substantial threat to sea turtles from egg to adult with over-harvesting and/or poaching of eggs and turtles (for food, oil and their shells), commercial fisheries (incidental take/bycatch), boating interactions(hull collisions and propeller wounds), pollution and coastal development(erosion and loss of habitat).
Q: What is a t.e.d.?
A: A TED, or Turtle Excluder Device, is a trap door set in shrimp nets to allow trapped turtles to escape. They are required on all U.S. shrimp nets. Sinkey Boone, a shrimper in Darien, GA, helped to design the first TEDs!
Q: What is archelon?
A: The Archelon is a prehistoric sea turtle that roamed the earth toward the end of the age of dinosaurs. They lived about 70 million years ago during the Cretaceous period, when much of the area was covered by water. Archelon had a shell 12 feet across and could have been 20 feet wide from the tips of its flippers and more than double the weight of today’s sea turtles. Remains of this mammoth turtle have been found in the plains of South Dakota! Its nearest living relative is the leatherback.
Q: What species of turtle crosses the causeway? Are these sea turtles?
A: Diamondback terrapins (Malaclemys terrapin) are aquatic turtles that live in the salt marsh. They are the only turtle in North America to live in brackish water (a mixture of salt and fresh water). Historically, diamondback terrapins were considered a delicacy as an ingredient in terrapin soup. Terrapins today face significant threats from automobiles as they cross marsh-causeways to lay their eggs. Many are also fatally trapped in crab traps, where they go I search of food.
Q: What is the northern nesting subpopulation of loggerheads? Why is it important?
A: There are many different nesting populations of loggerheads within regions. In the United States, the females nesting from northern Florida (Amelia Island) up to Virginia comprise a different genetic population than those nesting throughout the rest of Florida. This relationship is based on mitochondrial DNA analysis (mitochondria are inherited from mother to offspring and the DNA traces the lineage of a breeding population back through time). If this population is lost, it is not likely to be replaced. Therefore, even though Georgia may not see the high nesting numbers that Florida does, our contribution to the nesting population is still very important.
Q: Is that turtle dead?
A: No, the turtle is either sleeping or very sick. Just like when we are sick turtles get very weak and don’t feel like moving very much.
Q: Do you pump in seawater from the ocean?
A: No, we make our own saltwater here using Instant Ocean.
Q: What temperature is the tank?
A: The sea turtle tanks are usually in the mid to upper 70s.
Q:What salinity is the water?
A: The sea turtle tanks are usually the same salinity as the ocean, average of 35ppt. You can check other non-sea turtle tanks for the current salinity that is being used.
Q: What is red tide?
A: Red tide or as researchers prefer, harmful algae blooms (HABs), occur when microscopic, single-celled plants called dinoflagellates grow rapidly and accumulate near the surface. This bloom often causes the water to be colored red, green, brown, or orange. Not all algae blooms are harmful. In fact, algae are an important component of the food web. As energy producers at the base of the food web, algae provide other organisms with energy. Karenia brevis is a common alga that is associated with HABs in the waters of the gulf coast of Florida. These blooms can be harmful when potent neurotoxins or brevitoxins are released in the water. Sea turtles may get these toxins in their systems by eating crabs or other prey items that have become intoxicated.
Q: How do turtles sleep?
A: They will rest on the bottom and may even hide under rock or coral ledges. Remember they can hold their breath for a long period of time.