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Natural
Threats
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Over the millions of years of their existence,
turtles have survived major changes in the world's climate
and coastlines. Beaches around volcanic islands have exploded
into oblivion, coral reefs have provided cays and atolls
with new beaches, and huge changes in sea level have left
present nesting beaches either tens of meters above or beneath
the sea. They also face a host of other less catastrophic
natural threats to eggs, hatchlings and adults.
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Hatchlings
predated by fox (Vulpes vulpes)
Photo: © 1991 R. Salm |
This
sea turtle has lost a flipper to a shark, and cannot dig a nest
to lay its eggs. |
In fact, the odds are so heavily stacked
against turtles that only one or two of the many thousands
of eggs laid by a female through its lifetime will produce
a breeding adult.
Considering the great odds against their survival, it is remarkable
that turtles have survived successfully for so long, seeing
countless other species lapse into extinction along the way.
Some examples of the natural threats faced by turtles include
predators (e.g. foxes, raccoons, rats), flooding of nests
by high seas and rain water run off, and washout of egg clutches
from natural seasonal beach erosion.
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Nest predated by fox (Vulpes vulpes) |
Hatchlings
must run a difficult gauntlet on their way to the sea, with
seagulls, ravens, ghost crabs, feral dogs and foxes. In the
sea many a carnivorous fish or seabird will make a tasty meal
of them. It is thought that only about two or three hatchlings
in 10,000 actually survive to maturity at about 30 to 50 years
of age. As adults their only predators are sharks, humans and
sometimes seals.
Text adapted from "Sea Turtles in the Sultanate of Oman",
with kind permission of Rod and Susan Salm.
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