Leatherback turtles: going where few air-breathers dare

deep_turtle.jpg Story by Bryan Wallace, Duke University.
UW photo by Ed Standora.

Life in the deep sea is as far removed from a source of atmospheric oxygen as there is on Earth, but a select few animals do not let their need to breathe air limit the depths of their exploration. (No, I’m not referring to intrepid deep-sea human researchers.) These extraordinary critters frequently venture into the hostile conditions of the deep-sea, despite being vitally tied to air the above the ocean’s surface.

When you hear about deep-diving, air-breathing animals, you might first think of colossal sperm whales plunging over 1,000 meters to battle giant squid in the dark abyss. Or perhaps you think of massive elephant seals spending over an hour at depths over a half a mile down chasing prey. Maybe you’ve even heard of the deepest known diver of them all, the beaked whales, with recorded dives to over 2,000 meters. But what about turtles? Could a shelled reptile be suited for making dives where only a few whales and seals dare to go?


Leatherback turtles, like some whales and seals, possess remarkable adaptations for long and deep dives, with large onboard stores of oxygen in their blood and muscle, and special features like collapsible lungs (to avoid ‘the bends’), flexible shell (to respond to increased pressure at depth), and slowed heart rate (to conserve energy and oxygen stores). In fact, researchers have recorded leatherbacks diving to over 1,000 meters in different ocean basins (maximum reported dive was 1,230 m in the North Atlantic). Apparently, anything a whale can do, a turtle can, too.

To be clear, leatherbacks spend most of their time within the top 300 m of the ocean. These diving tendencies are likely due to leatherbacks’ air-dependence and because they feed primarily on jellyfish, like lion’s mane jellies and sea nettles, which tend to be concentrated at or near the ocean’s surface. However, leatherbacks are clearly capable of – and undertake – much more ambitious diving. The obvious question is: what are leatherbacks doing down there?

At this point, we aren’t sure what motivates a leatherback to plunge thousands of meters away from their most critical resource, but there are a few possibilities. Like other deep-divers, they might be pursuing prey. (Let’s face it; food is a strong incentive for any animal.) Perhaps they shuttle between different water temperatures in order to keep their body temperature stable, so an occasional deep dive into frigid waters could offset the heating effects of strenuous diving. Or maybe, like many other marine animals, they use the deep-sea as refuge to evade hungry predators, such as sharks and orcas.

Currently, we are using satellite telemetry to track several leatherback turtles migrating away from their Costa Rican nesting beaches to their high-latitude foraging grounds in the Eastern Tropical Pacific. Check out www.greatturtlerace.com to follow leatherbacks on their migration and to learn more about leatherbacks, the threats they face, and what is being done to protect them. Led by Stanford researcher George Shillinger, our group is analyzing leatherback dive profiles in relation to several oceanographic features to figure out just what drives leatherback diving. So far, all leatherbacks in our study have dived well beyond 300 meters on several occasions, and many have reached depths in excess of 1,000 meters. While leatherbacks have yet to reveal all of their secrets to us, hopefully our current efforts and those of our colleagues in other parts of the world will shed light on the dark side of leatherbacks’ deep-sea lives.

Tagged_turtle_w_ParkGuards_c_JBradley.jpg

© 2007 Jason Bradley • BradleyPhotographic.com

From left to right, pictured are Bryan Wallace (Duke University), Rotney Piedra (Director, Las Baulas National Marine Park), Carlos Diaz (Park Ranger), George Shillinger (Stanford University), and Guillermo Briseno (Park Ranger) aside one of the largest turtles in Great Turtle Race. This turtle weighs about as much as the 5 grown men sitting behind her. She laid 12 nests at Playa Grande this season before departing on her trans-Pacific migration.

Peter Etnoyer (406 Posts)

PhD candidate at Texas A&M University- Corpus Christi and doctoral fellow Harte Research Institute for Gulf of Mexico Studies.





80 comments on “Leatherback turtles: going where few air-breathers dare
  1. Sea turtles in the Gulf of Mexico are known to eat shallow benthic organisms like sea pens and sponges. These grow in deep sea environments, too. Is there any evidence suggesting deep diving turtles eat deep sponges?

  2. Great question, Peter. You’re correct that neritic sea turtle species (e.g. loggerheads, green turtles, ridley turtles) are known to go after invertebrates of all sorts. However, no one knows if leatherbacks (or maybe other sea turtles on a deep dive) are going after deep sponges. It’s possible, I suppose, depending on where they are. But often those really deep dives happen in REALLY deep water, where they never even approach the ocean floor.

  3. My Supervisor used to do quite some leatherback tracking work here in Malaysia but because they’re effective extinct these days, she now focuses her research (not tracking) on the green and hawksbill turtles (check out http://www.umt.edu.my/seatru).

    And we’re also trying to track a river terrapin (Batagur baska), a collaborative effort with Prof Herman from Acadia University, Canada.

  4. In response to Kiki’s question, collapsible lungs are made possible because of special cartilage that sea turtles and other air-breathing vertebrates have in their lungs that allow the lungs to be more flexible and collapse. Cartilage in our lungs is more rigid, hence no collapsing, at least not in beneficial ways. When a leatherback’s lungs collapse under pressure, the air in the lungs moves up into the trachea, which IS rigidly enforced by hard cartilage, but because no oxygen or CO2 is transferred across the walls of the trachea (like what happens in the lungs), the air just stays there until the animal ascends and the lungs reinflate.

    In response to ‘pelf”s comment, it is a shame about the Malaysian leatherbacks, and having learned that lesson, we are trying to make sure the same doesn’t happen to the leatherbacks in the Eastern Pacific. Check out http://www.greatturtlerace.com for more info on our efforts.

  5. Have you been able to identify or at least estimate the maximum dive depth for leatherbacks? If not, could you give us a hypothesis instead?

    Also, what is the average distance an individual you are tracking travels per day?

  6. In response to Heather’s questions, the deepest dive recorded for a leatherback is 1,230 m, recorded by Professor Graeme Hays of the University of Swansea, Wales, and his colleagues. As far as we know, leatherbacks can travel around 40-70 km/day (30-50 miles/day). The distances on the Great Turtle Race website are ‘retro-fitted’ to accomodate the 2 week lifespan of the site itself.

  7. Bryan, I’ve been to the site (www.greatturtlerace.com) and I just LOVE the cute turtles :)

    I’ll definitely blog about it as part of the awareness I’m spreading at my blog. In a while :)

  8. I’m glad you like the GTR site! Be sure to check out all the info on the site, including the education-related materials! And thanks for spreading awareness -that’s the goal!

  9. My son todd loves turtles they are his fav animal in the world he would like to know how big is this turtle u have displayed @ how old do u think she is
    thnku for yr time

  10. Thanks for your question, Liza and Todd. That turtle is about 150 cm long (> 5.5 ft), and we measure the curve of the top part of her shell (the carapace). She probably weighs about 250-300kg (600 lbs). As for her age, that’s one of the most important questions, but we have basically no idea! We wish they carried their driver’s license with them so we could find out! But seriously, size is not an indicator of age in these animals, and there are no other external traits that would indicate age. There are methods using bones to count rings that are formed over time (like counting tree rings), and those methods are not very consistent, and are giving us estimates of anywhere between 10-30 years to reach adulthood! So we like to say that any leatherback who is nesting is somewhere bewteen 10 and 1000 years old! That’s only kind of a joke…;)

  11. Hi:
    I’m a costarican biologist, getting my graduate degree in Louisiana. I love the picture of the leatherback in the beach! I worked with Rotney and his wife Elizabeth Velez, for six seasons at Langosta National Park and leatherback conservation is my life and passion. GREAT PAGE!!!

  12. what is the matter with you guys cant you see that your hurting the poor animal i hope you honestly get hurt like she did one day!!
    inconsiderate disguisting men!
    i despise you and your stpidity!

  13. hey guys i dont think that is right for you to take that turtle away from its home. i think you should put it back or put it in a new home for it and everybody can see it.

  14. Just one little question, but what are yall going to do with the leatherback sea turtle? Are yall going to let it go or keep it? I think that yall should let it go, because if you keep it than it might die,but if you let it go than it will probably live.

  15. Jordan, the leatherback sea turtle above was tagged with a satellite transmitter and released back into the ocean.

  16. I love turtles. I have on and i hope everyone can make a difference to the turtles!Alot of turtles need your help!

  17. I love turtles. I have one and i hope everyone can make a difference to the turtles!Alot of turtles need your help! You guys did a great job but if i were you i would let it go to the wild thankyou for the suport!

  18. Hi again everyone. It’s been a while since I responded to the comments to my article, and I’m thrilled to see all of the attention it has received! Thanks to everyone who has posted a comment, linked to the article, and shown interest in the story.

    To address the main questions about what happened to the enormous turtle in the photo, where is she now, etc., I’m putting together a new post. Stay tuned!

    bw

  19. I think that u should keep saving the turtles!!!!turtels Are one of my fave animals I LUV THEM!!! :) By the way #30 is right!!!!!!!!!!!!!!SAVE THE TURTLES!!!!!They need our help!!!!

  20. Wow, that is amazing. I have never seen a turtle that huge. I think they are the most fascinating animals alive. we need to stand and preserve the for the future for many more to see.

  21. Hello Turtle Lovers, I have just returned from Parismina, Costa Rica after volunteering with the local effort to save the leatherbacks. The island of Parismina is a beautiful place on the Carribean side of Costa Rica. My daughter Carin and I went there for a week as volunteers. we walked the beach at night looking for the turtles that have come ashore to lay their eggs. We participated in measuring, tagging, egg gathering, and some beach clean-up programs. It was an amazing experience that I will never forget. We stayed with a local family who fed us daily, invited us into their home and made us most comfortable while we were there. Poaching has decreased since the program started and the islanders show a respect for the turtles and the influx of funds that comes along with Ecotourism and awareness of the amazing resource that is the turtle population. Parismina is remote and wildlife of all kinds is abundant. Check it out! Sincerely, Dale

  22. That was horrible i mean who would hunt a turtle like that big it sucks THERE IS PROBABLY NOT THAT MANY OF THOSE ANIMALS LEFT.So please consider saving that turtle unless its already dead :-{…SAVE EVERY ANIMAL THATS ENDANGERED…THEY NEED OUR HELP!!!!!

  23. omg me and me friend r doing reaserch on turtles 4 our science project an i love thi info…….

    is there any other info on leatherback turles we could use..(mabe on classification)…????????

    coolio

    i

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