Page 166 - The Miracle of Migration in Animals

THE MIRACLE OF MIGRATION IN ANIMALS

they receive and move up to some 100 kilometers (60 miles) to their
nesting beaches, where they fertilize the eggs with their stored sperm.
The production of a clutch of eggs takes about two weeks, after which

the female lays as many as 120 eggs. She will repeat this process
about ten times in the same nesting season. During the nesting sea-
son, the female stays in the sea close to the beach, and at the end of
the season she returns to the feeding area without waiting for the
eggs to hatch. While in the nesting ground, the turtles feed very little
and gain the energy they need from the fat reserves they stored up in
the feeding ground.

How do they find the same place,

after covering a distance of thousands of
kilometers?

Females do not usually breed in two consecutive years. Some
species maintain an interval of at least two years and a maximum of
eight years between breeding migrations. But when the time comes to

go back to the breeding ground, the turtle returns to the same beach
as before, almost 2,300 kilometers (1,500 miles) away. That these rep-
tiles can find their way to this place thousands of kilometers away is
one of the most miraculous aspects of migration.
The eggs laid on the nesting beaches hatch in 7 to 13 weeks. Here
too, a miracle takes place. Unlike humans, sea turtles do not carry sex
chromosomes. The temperature of the nest determines the gender of
the offspring, and this determination occurs during the incubation
period. Warm nests produce exclusively female hatchlings, while
cool nests produce all males.
From the moment sea turtles open their eyes, it is obvious that
they act under the inspiration of God. With no experience to benefit

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