Meet Dr. Richard Reina
Dr. Richard Reina was one of the biologists on site at Las Baulas National Park. In the fall 1998, students interviewed Dr. Richard Reina, the biologist studying sea turtles at Las Baulas National Park in Costa Rica. In this interview, Dr. Reina discusses his efforts to help save the leatherback sea turtle. Here are his answers to students' questions.

Question: How many leatherbacks are there?
Reina: We believe that the population of leatherbacks in the national parks in which we work is a couple of thousand. And around the world, well, it's difficult to estimate the population, but it's probably less than 100 thousand.

Question: How many turtles do you see every night?
Reina: At this time of year, we are seeing between 7 and 14 turtles per night. This is close to the peak part of the season. We see them on the beach laying eggs.

Question: Are you optimistic about the growth of the sea turtle population?
Reina: I'm optimistic, provided we can resolve problems that are currently occurring. I think that leatherbacks can recover if we take effective action, particularly the problems of turtles getting caught by fishing boats.

Question: What do you think the long-term future is for the leatherback population?
Reina: I would say that in this particular park, unless there are effective measures to prevent the decline of the population, the turtles may disappear in ten years. Around the world in general, they would have a slightly longer time, but the same problem would still apply.

Many countries have passed laws that require fishermen to install devices in their nets that allow turtles to escape. And the work of conservation people is to try to have those laws enforced and introduce them into countries that don't use them currently. The devices are very effective. They apply particularly to the shrimp fishermen.

The other action that we are taking at the moment is to put people on fishermen's boats as observers to see more what the problems are and figure out how to solve them.

Question: Why did the number of leatherbacks decrease in 1996 to 1997?
Reina: We think it's probably because of the continuing problem that the turtles encounter such as being caught by fishing boats and from the pressure of other human activity — like beachside development and loss of nesting habitat. There may also be an impact of changing weather patterns from years when it is very hot and doesn't rain much. We think this might reduce the number of turtles that nest.

Question: How many turtle species are there?
Reina: There are seven species of sea turtle, and many more freshwater and land turtles. Besides the leatherback, the other sea turtles are the green turtle, the loggerhead turtle, the olive ridley turtle, Kemp's ridley, hawksbill turtle, and flatbacked turtle.

Question: Which is the smallest sea turtle species?
Reina: The smallest species is the olive ridley turtle. They usually weigh about 30 to 50 kilograms.

Question: How far north are turtles found? Most sea turtles are found in tropical waters, but leatherback turtles have been found much further north and south. Some have been seen close to Antarctica and as far north as Norway. They don't nest in those far north and south areas. They can migrate several thousand kilometers — and if they went as far north as Norway, many thousands of kilometers.

Question: Which ocean has the largest number of leatherbacks? Is there a reason for this?
Reina: Probably the Atlantic Ocean has the largest number, but I don't know why. It might have something to do with the many nesting beaches.

Question: What effects has global warming had on numbers of males and females?
Reina: We don't know if there has been any direct effect. There may be some impact because global warming does affect the productivity of sea water. But at this stage, we don't know if this is affecting the turtles themselves.

Question: Why were leatherback sea turtles able to survive the Age of the Dinosaur?
Reina: Probably because the leatherbacks lived in the ocean, which was a much more stable environment than the land was. Also, there were other animals, besides the leatherback, that didn't become extinct. Many reptiles, birds, and mammals survived the dinosaurs' extinction.

Question: Which turtle is the most endangered?
Reina: The most endangered turtle is probably the Kemp's ridley, and also the leatherback.

Question: What is the biggest threat to the leatherbacks?
Reina: There is more than one. The biggest threats are loss of nesting habitat and death of adults in the ocean. We believe the deaths are mostly due to pollution and capture by fishing boats. The loss of nesting habitat is often because of urban development.

Question: Which species of turtle is least in danger of becoming extinct?
Reina: Olive ridley turtles are the most numerous worldwide, with green turtles a close second.

Question: If sea turtles were to become extinct, how would it affect the environment?
Reina: This is difficult to answer because we don't fully understand all the relationships between different animals and plants in the ocean. Turtles are a natural part of the environment and if they were to disappear it would upset the balance that has existed for millions of years.

Question: Does the U.S. have netting laws?
Reina: Yes. The U.S. requires that shrimp-fishing boats use devices that will prevent them from catching turtles. It's a federal law, so all the states have to abide by it. However, not all fishing boats obey the law.

Question: Could a turtle survive without a flipper?
Reina: Yes. I have seen adult turtles missing one or both rear flippers, and they seem to do fine. The female turtles missing both rear flippers cannot dig a nest, however, so we have to help them. They don't seem to be aware that we are helping — they dig the nest as if we are not there, but in fact we are digging the hole for them. I have never seen a leatherback missing a front flipper, although I have seen other kinds of turtles without front flippers. How many of the turtles this year came in prior years to nest and already have a tag? I think it's about 30 percent. However, that is much lower than we would like, because it means that the remaining 70 percent have not returned for some reason. But we continue to tag new turtles that we've never seen before.

Question: What physical adaptations do leatherbacks have that have allowed them to survive?
Reina: Good question! Leatherbacks are very specialized, and their bodies are designed specifically for the marine environment. They are living in an environment and using a food source not used by very many other animals. You could ask the same about any animal — it's a difficult question. Animals are well suited to their environments, and that helps them survive.

Question: Are leatherback turtles related to dinosaurs?
Reina: They are not directly related to what we think of as the classic dinosaur. The turtles actually evolved and branched off from the dinosaur ancestors before the dinosaurs appeared. We can tell this from the fossils that remain, and from some aspects of the turtles' biology.

Question: Have you found any sea turtles with the same DNA?
Reina: No. None of the sea turtles have the exact same DNA, unless they are identical twins. However, if you compare the DNA patterns of the different turtles you can tell which ones are related to each other. As with all species, the baby turtles have DNA patterns that closely resemble that of their parents and so on. Some of the eggs that have been laid by the turtles here are particularly large, and it may be possible that there are twins in these eggs but we won't know for sure until after they have hatched.

Question: How much do leatherbacks weigh?
Reina: Leatherbacks weigh approximately 800 pounds. That's why we need to build the tripod for leverage to lift them.

Question:If the sea turtles accidentally eat plastic bags thinking they're jellyfish, does that mean they don't rely on their sense of smell when looking for food?
Reina:They probably do, but in the cases where they eat a plastic bag, they are relying mainly on their vision. The leatherback may grab the bag quickly as it floats past, and then try to spit it out. The turtle has special sinuses in their throats that are designed to trap food, and so if they catch the plastic bag, they have trouble spitting it out. If the plastic bag enters the turtle's stomach, it gets stuck because it is too large to pass out of the turtle's body. Eventually, a turtle's stomach can fill up with plastic bags, making it impossible to swallow any more food. And then the turtle starves.

Question: How old do sea turtles get?
Reina:Leatherback turtles probably live to be 30 to 50 years old. Other sea turtles may live a little longer.

Question: What can you learn from blood samples taken from the turtles?
Reina:Blood samples can tell a lot about an animal, including its genetic makeup and the levels of different hormones that control its biology. Blood also tells us about the turtle's nutrition and its general health. If a turtle is being kept in captivity, we would treat it for malnutrition. But, in the case of a turtle from the beach from which we take a blood sample, by the time we have the results of the sample, the turtle is gone. The blood sample, however, can help us understand what problems turtles are facing, and how we can address them.

Question: How long can sea turtles stay out of the water?
Reina:Turtles can stay out of the water for up to several hours when they nest. The main problem is that if they are out during the daytime, they get too hot. If they get hot and can't get back to the water, they will die. The heat makes them unable to move, and then they die from heat stress and dehydration.

Question: Does the sting of the jellyfish hurt the turtle?
Reina:Leatherback turtles can eat jellyfish that sting because they have a special way of neutralizing the sting in their stomach.

Question: What do the eggs in the incubator look like when they are ready to hatch?
Reina:They get a small split in the side as the baby turtle breaks the egg from the inside, and then as the turtle moves around, the egg splits on one side.

Question: What are the eggs that don't contain hatchlings used for?
Reina:We think that perhaps they are there to create air space in the nest, because as they dry out, they shrivel up and leave a hole behind.

Question: What color are leatherbacks?
Reina:Leatherback turtles are black. Other sea turtles are usually green or brown.

Question: How fast do leatherbacks swim?
Reina:They probably swim about 10 kilometers per hour, which is about 6 miles an hour.

Question: How do turtles see at night?
Reina:Sea turtles have excellent night vision because they live in the deep sea, where it can get quite dark even in the daytime.

Question: Is it possible to have twins in one egg?
Reina:Yes. This does occur, but it is very unusual, and the hatchlings that develop are smaller than the normal size. It will happen if there are two yolks in one egg. The twin hatchlings have less of a chance at survival because of their small size.

Question: Where do the sea turtles sleep? How do they breathe?
Reina:Turtles that live in shallow water — around a coral island — will dive to the bottom and jam themselves under a piece of rock or some coral and sleep there. They don't breathe while they sleep, but from time to time they wake up and swim to the surface to get air, and then go back down to sleep some more. They go up for air maybe once every one or two hours.

Turtles that live in deep water float at the surface to sleep. They sleep with their nostrils poking out of the water, so they can continue to breathe.

Question: Are there many encounters between swimmers and the turtles?
Reina:Around tropical islands, snorkelers and divers often see turtles, but in the deep water they are not seen very often. Leatherback turtles, however, are not seen frequently.

Question: How intelligent are leatherbacks?
Reina:It's hard to tell the intelligence of a leatherback turtle because they do not react very much to their environment. They can be frightened, but we don't see them doing very many unusual things. We do know that their brain is very small. Their nesting behavior is quite complicated.

Question: Do sea turtles communicate?
Reina:We don't know for sure if they communicate, but we think they probably communicate by sound and by sight. They make sounds that one another can hear, and they find each other by listening.

Question: Do leatherbacks get along with other sea creatures?
Reina:Yes, they get along with other sea creatures. They don't seem to have a particular relationship with any other animal, but they are certainly not aggressive or nasty.

Question: Do sea turtles bite?
Reina:No, I've never heard of anyone who was bitten. They do not react very much to people at all.

Question: We've read so much about the female turtle, but what role does the male have with the babies? Does he ever take care of them?
Reina:No, once the turtles have mated, the male has no further part in laying the eggs or the development of the hatchlings. The babies are completely independent once they're hatched.

Question: What time of year do turtles migrate?
Reina:The turtles that nest here migrate in September and October toward Playa Grande, and then in February and March away from Playa Grande. They are migrating from several thousand kilometers away, past the Galápagos Islands.

Question: At what age do turtles usually lay their eggs?
Reina:The first time they lay their eggs, they are probably between five and eight years old, but we haven't been able to identify this for certain.

Question: How often do the turtles lay eggs?
Reina:They lay eggs about seven times in one year, and then again two or three years later. They should be able to do this five or six times in their lifetime.

Question: We know that turtles come back to the same nesting beach, but do they pick the exact same area to build their nests?
Reina:No, the turtles will come up to many different places on the same beach — they don't appear to specifically choose one place.

Question: How deep in the ground do the turtles bury their eggs?
Reina:The eggs are in a hole about 70 centimeters deep, which is about 30 inches. And then they are covered with sand.

Question: What is the average distance between nesting sites?
Reina:I don't know what the average distance is — I'd have to calculate that on the computer. The sea turtles do seem to lay their eggs randomly in one particular suitable section of the beach, but they don't seem to keep any fixed distance between nests. They do nest on other parts of the beach, but most of the nests occur in that one-mile section. They prefer that section because of the slope of the beach, and so they have a wide area, but otherwise we don't know exactly what features they look for when choosing a section.

Question: Why do sea turtles nest only in tropical areas?
Reina:Most sea turtles live in warmer, tropical waters because they are cold-blooded. Living in warm water keeps their bodies warm. That's why they nest there, too. Also, because they lay their eggs on land, the eggs need to have a fairly warm temperature to develop. In a colder climate, the eggs wouldn't develop and the babies wouldn't be born.

Question: Do any other turtles lay eggs on the beach besides the leatherback?
Reina:There are also olive ridley turtles at the beach we're studying now. Different turtles nest in different parts of the world, but leatherback and ridley turtles are the ones generally found in this area.

Question: How can you tell when the sea turtle eggs are ready to hatch?
Reina:One thing we do find is that the temperature inside the nest increases because the hatchlings are moving around and generating heat. And just before they emerge from the nest, a sort of funnel shape forms, and then they come up. The babies dig upwards through the sand to get out.

Question: Do hurricanes affect the nesting process?
Reina:I think that if the storm produces very strong waves or currents, the turtles might wait until after the storm has passed before they come to nest. The other effect hurricanes have is they wash away thousands of nests when they hit the east coast of the U.S.

Question: How many baby sea turtles make it to the sea out of a nest?
Reina:If a nest has 100 hatchlings, at least 95 will probably make it to the water if they are born at night. But if the turtles come out of the nest during the day, most of them will get eaten. The five hatchlings that don't make it to the water at night are probably being eaten by a crab or a night bird. But even the ones that do make it to the water, their chance of survival is not great. There are many more predators in the water.

Question: How big are the baby turtles when they hatch?
Reina:Hatchlings are about 3 to 4 inches long, and weigh about two ounces. We believe that they grow quite quickly, and may reach adult size in as little as five years.

Question: How long does it take for a newborn turtle to develop its senses?
Reina:They are born able to see, hear, and move. Their senses are almost completely developed as soon as they hatch.

Question: Do the leatherback turtles know their babies?
Reina:No. After the mother lays the eggs and covers the nest, she returns to the water but does not come back to check on the nest. Leatherback eggs hatch after 60 days. The eggs are buried in the sand for protection and to keep them warm.

Question: How do baby turtles know they need to live in the sea?
Reina:Hatchlings are born with an instinct that makes them go straight to the sea, in the same way that many other animals know where they need to be. It's a fundamental question, like how do baby humans know that they need to walk, or how does a baby horse know that it can run? It's not a question of knowing that they need to do something — it's just an instinct that they're born with.

Question: How do you protect hatchlings from their predators?
Reina:We basically stand with them as they go to the water, so no predators can attack.

Question: How much do baby leatherback turtles eat?
Reina:We don't know what the exact quantity is, but we know that they must eat a lot in order to grow quickly. So they may eat their own weight every few days. They eat mainly jellyfish and other small animals.

Question: How much does a baby leatherback grow each day?
Reina:We don't know, because leatherbacks have not been kept in captivity. But they may grow one centimeter every couple of weeks, at a guess.

Question: Do you keep any of the baby sea turtles as pets?
Reina:No. We don't keep any as pets because they belong in the ocean. Also they would be enormous and require a huge swimming pool to stay in. It would be expensive. Leatherback turtles normally migrate very long distances, and so it would not be right to keep them in an enclosed area. But other sea turtles can be kept in a professional aquarium or a zoo.

Question: If the nests are underground, how do the hatchlings breathe?
Reina:There is enough air in between the grains of sand for hatchlings to survive without suffocating. It takes about 60 days for them to hatch, and once they're hatched, it takes an extra few days for them to dig out through the sand.

Question: Do some of the hatchlings not make it to the sea?
Reina:Yes. In each nest, a few hatchlings will probably not reach the surface of the sand. And under normal conditions, they will die in the sand. We do not dig up every nest, but if we find hatchlings that are stuck, then we will release them.

Question: What kind of a scientist are you?
Reina:I consider myself to be a conservation biologist. I have a Ph.D. in biology.

Question: Where did you first study sea turtles?
Reina:I started working at Heron Island on the Great Barrier Reef in Australia. There, I was studying sea turtles as well as helping to protect hatchlings from predators.

Question: What is the most difficult part of the work you are doing?
Reina:The most difficult part is spending all night on the beach in the pouring rain, and not getting very much sleep. For example, last night I started working at 10, and I went to bed at 5:30 this morning and got up again at 10:30.

Question: What is the most fun part of the work you are doing?
Reina:The most fun part is seeing a turtle lay a nest, and then two months later seeing the hatchlings come out of that nest. This year we are relocating nests to a hatchery because in the last couple of years, many of the nests have been destroyed by high waves.

Question: Does your family share your enthusiasm for sea life? Do they travel with you?
Reina:My family travels a lot — but they have not traveled to this project with me. They are also very interested in conservation in Australia. I'm going to see them at Christmas, when I go back to Australia. Frank Paladino will take over the project after I leave.

Question: What's the biggest sea turtle you've seen? How many pounds did it weigh?
Reina:The biggest sea turtle I've ever seen was a leatherback. She had a shell that was 180 centimeters long or 73 inches — that's just over 6 feet. She weighed about 375 kilos, which is over 800 pounds! I saw it here, in Costa Rica. Leatherbacks have been recorded that are much larger than that, but I haven't seen one.

Question: Do you study other animals besides sea turtles?
Reina:I have studied different animals in Australia including kangaroos, Australian lizards, and ants. But mainly I have concentrated on sea turtles.

Question: Why is this project so important to you?
Reina:I think that any animal that is in danger of extinction needs to be protected. For me, the leatherback turtles are special animals, and this project is important because it is something that I can do to directly protect and help them. By saving nests and studying the turtles' biology we can try to increase their numbers and understand better how to protect them. They are part of the entire ecological system of the earth, and so we must make sure that they don't disappear.

Question: How do you put the microchip in a turtle?
Reina:The microchip is injected into the muscle of a shoulder. First we clean the area with alcohol, and then quickly insert the tag. The tag then stays in the muscle without moving. The turtles do not react when we put the tag in. We also apply antibiotic cream to protect any infection.

Question: How do you weigh the sea turtles?
Reina:We let the turtles crawl into a big net, and then we build a tripod with a heavy winch to lift them off of the ground. We don't generally pick up the animals because they're too heavy.

Question: Will you control the temperature in the nests (or in the hatchery) to produce more females?
Reina:No. We are allowing the temperature to remain at its natural level, and to produce the sex that would naturally occur. We don't know what the best sex ratio is, so we don't want to control the temperature for that reason.

Question: Have you ever gone out in boats and/or submarines in search of leatherback turtles?
Reina:I wish I had submarines! I think that would be fun. I have been out in a boat looking for leatherbacks, but it is very difficult to find them. I have seen some from an airplane flying very low. But usually they are too far from shore to find them easily. It's hard for the boat to go out as far as they live, and plus they avoid the boat. All they have to do is dive under the water, and we can't see them anymore.

Question: Are you putting any satellite transmitters on the turtles?
Reina:We plan to put some satellite transmitters on turtles in January 1999, and hopefully this will tell us where the turtles go after they finish nesting. We'll be able to track them all over the world as they swim. The satellites are very expensive, so we are very happy to have them. I won't be here for that study — Dr. Frank Paladino will be here then.

Question: How do scientists use available technology to help save the leatherbacks?
Reina:By using satellite tracking and devices that record information on the diving abilities of the turtle, we can better understand where leatherbacks go and what they do when they're in the ocean.

Question: Are people supportive of your efforts to save the leatherbacks?
Reina:Yes, there are many enthusiastic people here who are concerned about the environment, and who are also helping to save the turtles. They help in different ways — sometimes by politics, and sometimes by actually working on the beach. Those people who volunteer in the field help us take blood samples and relocate the nests.

Question: What are the goals for helping the leatherbacks?
Reina:Our goals are to increase the population of leatherbacks in the world so that they can continue to live and nest in the numbers they have done for millions of years.

Question: What can we do to help the turtles?
Reina:You can learn about turtles and about the importance of conservation. You can tell people about the importance of protecting the turtles' environment. Also, you can — through your school or with your local community — tell the government and the business world that you are concerned about the issues of protecting sea turtles.

Question: How many volunteers do you have? Where are they from? What do they do to help the leatherbacks?
Reina:There are usually eight volunteers on each team. They mainly come from the United States and Europe. They stay for ten days. Volunteers come from many different types of backgrounds, and we train them when they arrive on the techniques for handling eggs and working correctly with turtles. Volunteers help us with all the different activities in our project — digging nests, working in the hatchery, etc.

Question: How do you keep the turtles' nests safe from predators?
Reina:Not many animals can dig deep enough to dig up leatherback eggs. Perhaps the only ones that could would be large dogs. Or maybe a jaguar. The babies are mostly preyed upon after they're hatched. Once they've hatched, it's much more dangerous because they can be eaten by birds, raccoons, dogs, cats, coyotes, and fish.

Question: If an adult female is hurt, would you take her to the hatchery for first aid or would you leave her alone? How would you carry her?
Reina:We would not be able to move an injured turtle. If we could give some first aid on the spot, we would try, but it would depend on what kind of injury she had. We couldn't move the turtle because she is too heavy. We could treat minor injuries such as cuts or bites, but we wouldn't be able to treat bad infections or major injuries — nothing that requires special medication. Turtles that are hurt that badly have to heal naturally.

Question: Do you ever move the nests? Why?
Reina:We move nests that are in danger of being flooded by high tides.

Question: Can sharks bite through a turtle's shell?
Reina:It would take a very big shark to bite through the shell of a leatherback. A leatherback shell is actually not very hard — not as hard as some of the other species of sea turtles. However, there is still bone underneath.

Question: Are turtles' shells their only defense mechanism?
Reina:A leatherback turtle is very large, so its size also provides some protection. They are also able to change direction very quickly in the water, so they can avoid predators that way too.

Question: How long does it take a mother to lay her eggs?
Reina:The entire nesting process lasts about two hours. This is from the time that the female emerges from the water to the time that she returns to the sea. Once she finally gets to a nesting spot, it takes her about 20 minutes with her front flippers to dig a pit for her body. It takes another 20 minutes or so to dig the nest chamber with her rear flippers.

When the hole has been dug as deep as her flippers will reach, she starts to lay the eggs. This takes about 20 minutes. Camouflaging or covering up the nest may take an additional 15 or 20 minutes.

Question: Why do sea turtles bury their eggs in the ground or sand? Turtles must lay their eggs on land and they are safest if buried away from predators. The sand or earth provides an insulated and stable environment for eggs to incubate.

Question: How do turtles eat jellyfish? The jaws of a leatherback turtle have scissor-like edges that assist in cutting soft prey. Its throat is lined with long spines pointed backwards to keep squishy prey from escaping while expelling excess water. Different species of sea turtles eat different kinds of food and their jaws are specially adapted to their diets.

Question: What does the scientist learn from the blood samples taken from the sea turtles? A graduate student here is doing a genetic study with blood samples to learn about the reproductive biology of the turtles. She's finding out whether the hatchlings from the same mother all have the same father. Blood can also provide information about hormones and biochemistry of the turtles.

Question: Are Costa Ricans supportive of your efforts? In general most Costa Ricans want to preserve their environment and are supportive of conservation programs. Some people have different ideas on what is the best way to do this but still have the same general goal. There is pressure though from some tourism-based industries that see conservation work as obstructing the opportunities for business.

Question: How do leatherback turtles communicate? We don't know for sure if turtles communicate, but we think they can probably communicate by sound with each other under water.

Question: How many of the leatherbacks' eggs survive? The number of eggs that survive varies, but usually 50 to 70 percent of the eggs hatch. However, last year only 8 percent of the eggs hatched at Playa Grande due to flooding from unpredictably high tides.

Hatching success varies from season to season and between individual females. The success rate is influenced by the condition the eggs are in when the embryo is developing. For example, the temperature and moisture levels of the sand play an important role.

Question: Why are leatherback turtles valuable to poachers?
Reina:Poachers can sell the eggs at high prices.

Question: How do sea turtles breathe under water?
Reina:The turtles comes up to the surface of the water to breathe. They take several quick breaths before they dive in again.

Question: How big was the largest leatherback you've ever found?
Reina:So far this season at Playa Grande, the largest turtle is 160 cm long by 123 cm wide. She came up on the beach on the night of October 31 to nest. The average turtle size in 1997 was 145 cm and the minimum was 129 cm.

Question: How deep can the leatherback turtle dive and how long does it stay underwater?
Reina:Sea turtles have been recorded as diving to more than 1,400 meters (4/5 miles). They have several special adaptations that allow them to stay under water for around one hour.

Question: How can you tell a male and female leatherback apart?
Reina:The males are slightly larger and have a longer tail, otherwise they look the same. Only sexually mature males have a longer tail — when the turtles are young it is impossible to tell them apart. It is more difficult to study males, as they do not come out of the water. Most studies have focused on nesting females.

Question: Is there a commercial use for the turtles?
Reina:People sell the turtle eggs to be used in cooking. Their blubber is also used for various oil products — lamp oil, skin lotions. Leatherback meat is not supposed to taste good, so they are not generally killed to eat.

Question: How many eggs does a mother turtle lay?
Reina:A nesting female lays about 60-70 large, pool-ball-sized eggs and around 30 smaller eggs. The small eggs have no yolk in them, and so no hatchling develops. We are not completely sure what role the small eggs play.

Question: Are the turtles afraid of people?
Reina:The lights on a beach at night and the noise and activity of people can cause a nesting female to return to the water before she lays her eggs or even keep her from coming up on the beach at all.

Question: What is the main cause of death of leatherback turtles?
Reina:The main reason the species is close to extinction is because of human activity, such as beachside development, discarding of debris into the ocean, poaching of eggs, and capture by fishing vessel.

Question: How big are the babies when they first hatch out of their shell?
Reina:The hatchlings are about 75 to 85 millimeters long when measured along the shell. They weigh about 50 grams.

Question: Why are the sea turtles called leatherbacks?
Reina:The appearance of the turtle's shell is what gives them the name "leatherbacks." The shell looks like leather. It is actually a layer of thin, tough, rubbery skin. The leatherback is the only turtle without a hard shell.

Question: How can you tell the turtles apart?
Reina:It is difficult to tell most leatherback turtles apart. There is a pink spot on the turtle's head unique to each individual. Flippers may be scarred or missing, or there may be evidence of shark bites. The way biologists identify different turtles is to use an electronic microchip tag like the ones used to identify dogs and cats. This is put into the muscle of the shoulder and is read with a small scanner.

Question: Do you think turtles make good pets?
Reina:Many turtles are endangered and are going extinct because of the pet trade. So it is important to find out as much information as possible about the kind of turtle that you want. Is the turtle endangered or restricted?

Go to the library, talk to people who own turtles, join a club. The easiest turtle to have as a pet is the slider turtle, but they also frequently carry salmonella, a bacteria that can make you very sick. Turtles such as Chinese box turtles make good pets, but they can get very big. Turtles have very different requirements. They eat different things, need different kinds of spaces. It also takes a lot of work to keep them clean.

Question: Do you use a spotlight at night to help the baby turtles as they hatch so that birds don't eat them?
Reina:No, we don't use a spotlight. Actually the hatchlings are safest from natural predators when they are under the cover of darkness.

Question: What made you interested in sea turtles? I find sea turtles to be very mysterious animals. They lead secret lives, which lead to great opportunities of discovery. I am also interested in learning about how marine animals are able to dive to such great depths.

Question: What is the most endangered turtle in the world?
Reina:Kemp's ridley is the most endangered sea turtle.

Question: How old do leatherback turtles get?
Reina:That's a hard question to answer. We estimate that leatherbacks are sexually mature when they are less than 10 years old, and we think that they may live to be 40 or 50 years old.

Question: Is it true that you can tell a turtle's age by the number of squares on its shell?
Reina:As turtles grow, their shells grow along the edge of the scutes (the square parts). Sometimes thin lines can be seen that indicate age — like the rings of a tree.

Question: Do males and females differ in their behavior other than egg laying?
Reina:The males are slightly larger. They have a tail that is three to four times longer than females. Otherwise there are few differences. It is more difficult to study the males, as they do not come out of the water. Most studies have focused on nesting females.

Question: Why do the turtles come back to the beach where they were born to lay their eggs?
Reina:One theory is that they navigate by the magnetic field. They may also use imprinting, where their sense of smell and taste guides them.

Question: Why do the nesting females return to the water, leaving their eggs on the beach?
Reina:Water is the natural habitat of leatherbacks. The nesting females are not able to stay on land for long. They will overheat. They can stay on land up to about four hours.

Question: How does Earthwatch help you with your studies?
Reina:Earthwatch helps our project by providing funding and volunteers to assist us.

Question: Do you have any final words for the audience?
Reina:Thank you very much for your interesting questions. I hope this project has motivated you to learn more about turtles and more about biology.