A few turtle facts.  Turtles are reptiles with a small brain.  They nearly impossible to train and therefore have little “learnt” behaviors.  During the last part of the quarter moon turtles start to arrive to lay eggs.  A few at first, but at it’s height there will be thousands at a time in one location.  One square meter of beach at Ostional will have as many as 16 nests. Generally, the turtles come in at the dark of night, and will pick a location close to the shore, mid beach, or high near the vegetation line.  They then start to dig with their back flippers.  The alternate, they jam their flipper down straight, curl it to scoop sand, then place it outside the hole, then brush it away.  This will repeat until a maximum depth is found.  She then will place both back flippers over the hole and start to lay.  Eggs come out, 1,2,3, and sometimes 4 at a time falling into the hole.  The species I observed (Olive Ridley) laid between 80 and 110 (The max number I observed).  When done, she fills the hold, then rocks her shell back and forth to pat down the sand, then move around to camouflage the nest.  They then return to ocean, where they live a solitary life.  A mother may return 2-3 times a year to lay eggs.

The scooping of sand out is a very complex behavior.  It is used nowhere else in their natural life.  Moreover, they are not raised by a parent, so turtles are on their own from day 1 until they lay eggs again.  How do they know how to do this?  There is no Lamaze class for expectant turtle mothers, and there is no evidence of communication.  If missing a flipper, the turtle will still attempt to dig.  She will continue to cover and camouflage the next if the eggs were taken while laying — essentially covering an empty nest.  In the the words of a Phd student I met there (Christina), they are “pre programmed” to do this activity.  It is an “instinctual activity” she said.

To me this falls short.  Where did the instinct come from?  Evolution says that over millennia, turtles that did not bury eggs in the sand died out, thus building a genetic memory to dig and camouflage.  However, there must have a been a group that did it first, so how did they figure it out?  Going back to the same beach where they were born is understandable to me (Although I wonder what would happen if eggs were transplanted to another beach).  Religious folk would call this “instinct” programmed by a creator.   It seems mysterious and wondrous to me!

A couple of quick notes about what pictures don’t show.  The beach is littered with broken shells from millions of hatching.  There are more turtle shells than sea shells.  Vultures, dogs, and crabs are plentiful, predating on newly deposited shells.  At night we would patrol the beach.  Measure and count turtles, their eggs, nest depth, and location.  During the morning we would do  a census.  One morning I did census prior to the arribada and found 36 exits from the ocean and only 5 nests remained in tact.  The rest were poached by people to sell turtle eggs on the black market, by dogs to eat, or were false exists where the turtle was unsuccessful in making a nest or was frightened off.

Some of my favorite non visual memories of this event was 1) The labored breathing of the turtle while laying eggs.  2) The group of people supporting turtle.  At times we would sit there quietly at 2 in the morning, under the milky way, listening to the waves and turtle, until our measurements were done.  Earlier in the evening 8-12 shifts are crowded with people and frequently with obnoxious people.  3) One job was little pick up, which entailed removing trash, moving large wood to the vegetation line, and filling in holes so turtles don’t get stuck.  It felt great, after doing this, to then see 15 turtles use the section of the beach that I cleared.