Ocean
Watch
Monday, September 4, 2000
Turtles find
propagating
hard labor
Labor Day means different things to different people.
The holiday was created to honor our country's workers. But since
organizers selected the first Monday of September as the official day of
rest, Labor Day also came to symbolize the end of summer.
To me, whose mother went into labor one long-ago Labor
Day, subsequently producing a baby brother, Labor Day is a reminder of the
pain most women endure to give life to their children.
Reproductive laboring is not restricted to humans, of
course, nor even to females. Some marine animals labor in extraordinary
ways to perpetuate their species.
Consider octopuses, which get only one chance to do it
right. A male octopus becomes sexually mature when he is a year or two
old. At that time, he seeks out a receptive female into which he delivers
his packet of sperm.
Having completed the one big job of his life, he dies.
Female octopuses don't have it any better. After
fertilization the female lays her eggs, then guards and tends them. The
mother octopus stops eating during this period and dies when the
youngsters are safely hatched.
This one-time, all-out reproductive burst is controlled
in both male and female octopuses by two round glands located near their
optic tracts. When researchers remove these glands in brooding females,
they leave their eggs, resume eating and live a longer life.
At the other end of the extreme are Hawaii's green sea
turtles. During a life span that may last 60 years or more (no one knows
exactly), a normal female turtle produces thousands of eggs, sometimes
laying up to five clutches of about 100 eggs each in just one season.
But before the females get to lay those eggs, most must
swim about 500 to 800 miles, one way, through open ocean to the northwest
islands of French Frigate Shoals. This atoll, located in the middle of the
Hawaiian Islands National Wildlife Refuge, is the last major breeding site
for Hawaii's green turtles. Because the turtles' feeding grounds are in
the main islands, reproducing for Hawaii's greens requires first a long,
rough journey.
Another form of labor for female turtles is getting
their eggs fertilized. Ardent males often hang onto the backs of females
turtles for hours, forcing them to swim around with the free-loading
inseminators on their backs.
Little wonder females reject all suitors after laying
that first clutch of eggs.
Once fertile and in the atoll, a female turtle then
must crawl high up a sandy beach and then haul herself around to search
for a suitable nesting spot.
This moving about on land is difficult for an animal
with flippers more suited for swimming than walking.
The turtle drags her heavy body through the sand one
lunge at a time, then often spends hours or even entire nights looking for
that perfect place.
When she finds it, the turtle painstakingly digs a hole
with her rear flippers, scoop after scoop, until finally, it's deep enough
to deposit her eggs.
I was once lucky enough to watch this remarkable event
and it is intense labor indeed. Female green turtles' reproductive effort
is so energy-sapping that they take two to five years off before migrating
north to do it again.
This Labor Day I'm appreciating a day off and
celebrating the end of a memorable summer.
But I'm also remembering all the moms and dads in the
world, human and non, who work so hard for their offspring.
Parents, have a restful day.
