Hello, my name is Mr. Hill. Please join me as I travel to Costa Rica to study sea turtles!

Monday, January 31, 2011

Day Two: Early Afternoon

Because I was assigned to the early morning (5 a.m. to 7:30 a.m.) beach shift today (more about that below...), I wasn't on the roster to go out last night. But out I went -- for half the shift (9:10-midnight), and I'm awfully glad I did! My group, assigned to north Playa Grande beach, didn't spot any leatherbacks, but we did get to see olive ridley hatchlings making their way from the nest to the water -- so cool. I'm guessing there were about 80 or so hatchlings -- about 2.5 inches top to bottom, crawling their way across the sand and into the surf. Two members of our group measured the hatchilings -- height, width, and size of head -- and recorded their findings while the rest of us made sure predators kept their distance. About 20 minutes later, we saw a black turtle come ashore to lay her eggs, but, alas, she had other plans, so no luck there: she did a U-turn and headed back into the water!

Another group -- sweeping south Playa Grande beach -- did get to see a leatherback, but, like our black turtle, she executed what they call a false crawl: in; change of mind; back out. These false crawls aren't uncommon, and the chances are good that the same turtle will return either later that night or the next night to lay her eggs.

Night patrol goes out three hours before high tide and stays out for three hours after -- 6 hours total. When high tide occurs before, right around, or very shortly after midnight (as it did last night), two people are assigned to the morning walk shift to see if there was any activity after the night patrol finished its sweeps. I went out this morning with one of the biologists, and we found two little olive ridley hatchlings doing their darnedest to get to the water -- yep, they were stragglers from the same nest that produced the large batch the night before! The biologist and I picked up the two tiny things and helped them get to the water a bit more quickly than they might otherwise have arrived there. They were very cute, I must admit: the one I held (remember: all of 2-2.5 inches long) took the opportunity to use its front flippers to wipe the sand out of its eyes -- a total 'awwww' moment.

This afternoon the project manager will give us a presentation on the leatherbacks, and then at 3:00 we're going to the hatchery to participate in the excavation of a nest.

I have beach patrol tonight, and high tide is later than it was last night, so I will be out from approximately 10:00 p.m. until 4:00 a.m. It's a late high tide (as I think it will be for the rest of the week), so there will be no morning walk for anyone tomorrow.

Some more Turtle Fun Facts 4 U:
  • no one knows for sure what the life expectancy is for a leatherback, but they estimate it to be about 80 years
  • olive ridleys lay approximately 100 eggs each session, and close to 80% of those eggs will hatch -- that's a higher percentage of hatchlings than the leatherbacks enjoy
  • leatherbacks crawl using both front flippers simultaneously -- they more or less 'swim' through the sand; olive ridleys alternate their front flippers, so they crawl -- who knew?

Lower schoolers: thanks for the questions! I will make sure to ask them at this afternoon's session with the project manager. Look for the answers in a later post.

3 comments:

  1. Hi Mr. Hill,
    This sounds like a ton of fun, and also really interesting! I have a few basic questions about your experience. Firstly, there are many endangered (or threatened) species that you could be working with - why did you choose turtles? Did you have prior interest in them, or a pet turtle as a kid? Secondly, why did these turtles become endangered (or threatened) in the first place? Was it because of human interference? And also, why can't they survive on their own (why do they need human help/hatchery duty)?

    Hope you encounter some cool animals and enjoy the warm weather, apparently you're going to miss some intense NY precipitation.

    raphael

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  2. Hey Mr. Hill,

    Hope you're enjoying the trip (it sounds like you very much are). I was wondering about the 'false crawls'. Do you know the reason behind these hesitations? Does the turtle not find the area habitable for her eggs? Does she not think the area is safe? Or is there no reason at all?

    That's basically it. Enjoy the rest of your trip, and I'll see you (probably only from the chest up) on Thursday at assembly.

    -rashaad

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  3. 4M Stripes in ScienceFebruary 4, 2011 at 9:30 AM

    Hi, Mr. Hill, from 4M Stripes in Science....

    Thanks for your great blog. We still have a few questions.

    1) If the babies hatch during the day, do they wait until night to come out of the nest?

    2) If you see a hatchling, why don't you just bring them to the water?

    3) How do leatherbacks eat jellyfish without being stung?

    Thanks, and have a great trip!

    4M Stripes in Science

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