Artwork by Mike Yap |
To
develop an appreciation for something can take as little as a glimpse – an
instant connection – or sometimes a profound amount of time to see the beauty
within. In the life of James Spotila, a remarkable sea turtle biologist, it
only took a sighting of a healthy leatherback about to lay its eggs to be held
captivated by it forever. Such a moment held a big part of him, enough to
commit his lifetime into studying these wonderful, often miraculous sea
creatures.
Since
World Sea Turtle Day, June 16, is especially dedicated to the 7 sea turtle
species (Green turtle, Leatherback, Kemp’s Ridley, Olive Ridley, Hawksbill,
Loggerhead and Flatback) we have today, let us take the time to see how amazing
and resilient they really are.
1. Did you know that sea turtles don’t
have sex chromosomes? Instead,
sex is determined by temperature at which eggs incubate. In the case of green
turtles, at 28oC, hatchlings develop into
males; at 31oC the hatchlings grow into
females [1]. This has great implication in conservation [2].
2. The largest recorded leatherback
turtle weighs nearly a ton [1].
With jellyfish as its main food, it’s kind of hard to imagine how much it has
to eat to weigh that much.
3. Sea turtles have magnetite in their
brains; they use it as their internal magnetic compass [1]. They don’t have the
superpowers of Magneto but they are tuned to migrate thousands of miles in the
ocean and get back to the beach were they hatched.
4. Different species bury their eggs
in sand at varying depths. Don't
worry the eggs have porous shells so they can breathe. The
shallowest depth is observed for Olive ridley and Kemp’s rildey nests at 15
inches while the deepest is for leatherback eggs buried at 25 inches. The
deeper it is, the more stable the temperature [2].
5. Sea turtles have to spend at least
a decade or more in the open sea before going to back to mate and reproduce in
their natal beach [1].
Imagine that they are already independent from the time that they were
hatchlings, racing to the open sea. It only becomes tougher (and tougher) for
the succeeding years as they have to avoid being captured in destructive shrimp
trawls, longlines, and gillnets. What is more worrisome is their affinity to
ingest plastics which they mistake for a sumptuous jellyfish.
6. Sea turtles are excellent divers
and can prolong their breathing underwater for 45 minutes. The deepest dive a leatherback has
bagged is 4250 m [3], beating that of a sperm whale at 3686 m [1].
7. They have survived the mass
extinction which obliterated dinosaurs and so have lived for 110 million years
now [1]. And it is of course
in our hands to make certain that they get to be seen and conserved by the next
generations.
The list
of how beautiful sea turtles are goes on. Never cease to see and celebrate
what’s amazing.
We have considerable
information on the seven species of sea turtles. Feel free to visit us at
SeaLifeBase, or become a collaborator. Happy World Sea Turtle Day!
_________________________
[1]
Spotila, J.R. (2004). Sea Turtles: A Complete Guide to their Biology, Behavior
and Conservation. The Johns
Hopkins University
Press.
[2]
Spotila, J.R. (2011). Saving Sea Turtles. The Johns Hopkins
University Press.
[3] OBIS Search Interface. http://www.iobis.org/mapper/
[Accessed 6/8/2015].
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