1. Welcome! Are you interested in tortoises? If so, we invite you to join our community! Our community is the #1 place for tortoise keepers to talk online. Once you join you'll be able to post messages, upload pictures of your tortoise and enclosure, and discuss any tortoise topic with other tortoise keepers. Get started today!

The science of giant tortoise flips

Discussion in 'Tortoises in the News' started by Mizcreant, Dec 5, 2017.

  1. Mizcreant

    Mizcreant Well-Known Member

    Joined:
    Nov 13, 2017
    Messages:
    940
    Likes Received:
    938
    Trophy Points:
    93
    Location (City and/or State):
    Cincinnati, OH
    Studying giant tortoise flips without tipping the animals over is a delicate business

    When getting back on their feet, shell shape matters for these reptiles
    BY
    SUSAN MILIUS
    9:00AM, NOVEMBER 30, 2017


    [​IMG]

    ROOM TO REACH An extreme shell form called a saddleback on some species of Galápagos giant tortoises raises questions about how shape matters.

    It would be a memorable sight. But it would also be so wrong to tip over Galápagos giant tortoises to see how shell shape affects their efforts to leg-pump, neck-stretch and rock right-side up again.

    Shell shape matters, says evolutionary biologist Ylenia Chiari, though not the way she expected. It’s taken years, plus special insights from a coauthor who more typically studies scorpions, for Chiari and her team to measure and calculate their way to that conclusion. But no endangered species have been upended in the making of the study.

    “They’re amazing,” says Chiari of the dozen or so species of Chelonoidis grazing over the Galápagos Islands. Hatchlings start not quite the size of a tennis ball and after decades, depending on species and sex, “could be like — a desk,” says Chiari, of the University of South Alabama in Mobile.

    Two extremes among the species’ shell shapes intrigue Chiari: high-domed mountains versus mere hillocks called saddlebacks because of an upward flare saddling the neck. Researchers have dreamed up possible benefits for the shell differences, such as the saddleback flare letting tortoises stretch their necks higher upward in grazing on sparse plants.

    [​IMG]
    CLASSIC DOME In a new analysis of shell shape as a factor in recovery from terrifying tortoise tipovers, it was domed shell (shown) versus saddleback as real-world possibilities.

    At the dryer, lower altitudes where saddleback species tend to live, fields of lava chunks and cacti make walking treacherous. “I fell on a cactus once,” Chiari says. Tortoises tumble over, too, and she wondered whether saddleback shells might be easier to set right again.

    She went paparazzi on 89 tortoise shells, taking images from multiple angles to create a 3-D computerized version of each shell. Many shells were century-old museum specimens from the California Academy of Sciences in San Francisco, but she stalked some in the wild, too. The domed tortoises tended to pull into their shells with a huffing noise during their time in front of the lens and just wait till the weirdness ended. A saddleback species plodded toward the interruption, though, butting and biting (toothless but emphatic) at her legs.

    To calculate energy needed to rock and roll the two shell types, Chiari needed to know the animals’ centers of mass. No one, however, had measured it for any tortoise. Enter coauthor Arie van der Meijden of CIBIO, Research Center in Biodiversity and Genetic Resources at the University of Porto in Portugal. With expertise in biomechanics, he scaled up from the arthropods he often studies. For a novel test of tortoises, he arranged for a manufacturer to provide equipment measuring force exerted at three points under a tiltable platform. As the first giant tortoise, weighing in at about 100 kilograms, started to lumber aboard the platform at Rotterdam’s zoo, Chiari thought, “Oh my gosh, it’s going to crush everything.” For a gentler and more even landing, four men heaved the tortoise into position.

    Calculating the centers of mass for Rotterdam tortoises, the researchers extrapolated to the 89 shells. The low, flattened saddleback shape actually made shells tougher to right, taking more energy, the team reports November 30 in Scientific Reports. Now Chiari muses over whether the saddle at the shell front might let freer neck movements compensate after a trip and a flip.

    Source: https://www.sciencenews.org/article/tipped-giant-tortoise-shell-shape-matters
    Oxalis, TammyJ, Bambam1989 and 2 others like this.
  2. Big Charlie

    Big Charlie Well-Known Member

    Joined:
    Jul 28, 2015
    Messages:
    2,629
    Likes Received:
    3,000
    Trophy Points:
    113
    Location (City and/or State):
    California
    (These ads do not appear for registered members.)
    I love this!
  3. TammyJ

    TammyJ Well-Known Member

    Joined:
    Jun 21, 2016
    Messages:
    1,800
    Likes Received:
    1,187
    Trophy Points:
    113
    Location (City and/or State):
    Jamaica
    It seems kind of obvious just looking at them that the more domed shell would better facilitate flipping/rolling back over.
    Also, I would think that pyramiding could actually totally prevent any tortoise from getting back upright?
    Maybe I am wrong? Maybe the pyramiding would give it more "traction" to start with?
    I would love to know which would be easier.
    TechnoCheese likes this.
  4. Oxalis

    Oxalis Well-Known Member 5 Year Member

    Joined:
    Jan 5, 2013
    Messages:
    2,703
    Likes Received:
    2,794
    Trophy Points:
    113
    Location (City and/or State):
    Michigan
    It's always good to have some follow-up questions for further research!! :cool:
Similar Threads: science giant
Forum Title Date
Tortoises in the News Don't Buy Sulcata Tortoises - Giants Overwhelm U.S. Rescues Feb 3, 2016
Tortoises in the News Yangtze giant soft-shell turtle --- 3 left Feb 2, 2016
Tortoises in the News Yangtze giant softshell turtle conservation Jun 6, 2015
Tortoises in the News Quick article and video of a giant tortoise eating some salad. Feb 3, 2015
Tortoises in the News Giant sea turtle photobombs wedding May 24, 2014

Share This Page