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Marine Turtles

By J. Fretey (National Museum of Natural History of Paris - Zoology Lab)

What size can they attain?
The Leatherback turtle is the largest of the Chelonian specie. The females seen in French Guiana have an average shell length between 1.5m to 1.9 m, the longest reaching about 2.4 m ( the famous Galapagos giant turtle mesures about 1.2m). The South American Green turtles are the biggest in the world with their shells measuring more than 1m in length. The Olive turtles are the smallest: from 0.6m to 0.75m.

How much do they weigh?
TurtleIt has been falsely written that the Leatherback turtles can weigh a ton or more. The average is more around 400kg and the maximum auround 650kg. The Green turtles and "Caouannes" can weigh more than 200kg.
What's their life expectancy?
No one is really sure. In order to know, one has to tag the newborn babies and study them until their death (which can take several generations of researchers). We have obtained several historical examples: certain specimens of land turtles have lived more than 150 years. A "Caouanne" has been kept in captivity for 30 years.

Where do they lay their eggs?
Leatherbacks: NE South america, Central america, SE Africa, SE Asia. Green turtles: NE South america, Indian ocean ilands, Australia, Borneo, Central America, West indies, New Guinea and Galapagos. Olive turtles: NE South America, Mexico, Costa Rica, SE USA. "Caouannes": Australia, Florida, Mediterranian. "Imbriques": Seychelles, Central america, Borneo, New Caledonia.

How many eggs does the female lay?
The leatherback lays between 50 to 150 eggs. 30% of theese are sterile. The fertile eggs, about 51mm in diameter, are spheric in shape with a soft and wrinkled membrane. The Green turtles lay around 120 to 200 eggs, the "Caouanne" 60 to 150 eggs and the Olive turtle 80 to 90 eggs.

How often does the female lay eggs?
According to recent reasearch results, we think that the Leatherbacks and the Green turtles lay 3 to 7 times per season, with a 12 day interval between these periods. The rhythm of the reproduction season is not yet known: perhaps from 3 to 4 years.

How do they build their nest?
They dig a hole with their hind legs. The sand dug out by a hind leg is swept off the side by the other hind leg. The finished nest takes the form of a boot. Their depth can reach about 80cm for the large species.

What happens during the incubation of the eggs?
Once they've laid, they cover the eggs with sand, and return to the ocean, leaving them to develop independently. The incubation lasts from 45 to 65 days, according to the species and the climatic conditions. The normal temperature of Leatherback nest is constant around 29°c. At some point of the incubation a tiny decrease or increase of this temparature defines the sex of the babies (which will therefore all be males or females).

What do we know about their migrations?
Very little actually. Tagged turtles found on the Surinam/ Guyana coast have been found later on the New Jersey & Texas coast. One of them, observed in 1970 was later captured in Ghana, about 6700km from departure point.

What do they eat?
They are essentially carnivorous (fish, jelly fish, mollusks, shellfish), with the exception of green turtles who, when adults principally eat algae.
 

Things to do and not to do while observing the turtles:

You can: get close to the turtles after they've started digging for a few minutes. Take pictures or film during digging, laying and departure, but never when the turtles land on the beach. Speak loudly but not during the arrival.

You must not: Climb on the turtles, disturb the arrival (by getting close, making noise or pointing a flashlight), light a fire, direct light towards the ocean or the eyes of the turtle (no flash in their faces), touch or take the eggs.
 

Where, how and when to go to see them:

The peek of the laying season goes from March to June.
The Ameridien village of "Awala-Yalimapo" is the place. Its beach is called "les Hattes". From Kourou you take "St-Laurent" direction and a few kilometers after "Organabo" you turn right, direction "Mana" town. In the middle of "Mana" turn left at the only town sign, direction "Awala-Yalimapo"/ "Les Hattes", and go to the end of the road. One way trip is 200 km.
You need to be there 2 hours before till 3 hours after high tide. And best is a day with a high tide very end of afternoon or beginning of evening.
You need to bring full gas tank, bug spray, long clothes, lamp, ID papers, some money and a hammock with a net if you plan to sleep there.

For Tide hours and further information don't hesitate to contact us...