The Leatherback Turtle, also known as the 'DaaraKasbawa' or 'Thel Kasbawa' in Sinhala, is the largest species of turtle amongst the extant modern species and is unique in its lack of a bony shell. Instead it has tough leathery carapace with several raised longitudinal ridges which run its length. Adults average between 1-1.75 metres and weigh between 250-600 kg in weight. The largest official recorded individual is 650kg found on Pakistani shores. However there exists a report of a turtle weighing 916kg known as the "Harlech Turtle". The weight is under speculation as the individual’s preserved carapace measures only 1.5m long.
The Leatherbacks also have white spots on their carapace and large front flippers, the largest fin to body ratio of any turtle. They are omnivores and their diet consists mainly of algae, shrimp and jellyfish. They have a unique circulatory system where they are able to maintain a high body temperature despite being cold blooded in cold waters enabling them to dive extremely deep (up to 1200m) in search of jellyfish. This is aided by constant generation of heat through muscle activity and a high body fat content which prevents heat loss.
Leatherbacks also happen to have the widest global distribution amongst all of the other sea turtle species. These turtles areconsidered to be a threatened species but can be rarely seen nesting on Sri Lankan shores.
They lay clusters of 80-100 eggs and re-nest about five times at 10 day intervals and return to nest again after a period of 2-3 years.
The Loggerhead turtle,also known as the 'OlugediKasbawa' in Sinhala due to its seemingly overproportioned head,is the largest hard shelled sea turtle and is slightly larger than the green turtle, weighing on average 100-200 kg and measuring 70-100cm in length. However much larger individuals exist. Their skin and carapace ranges in colour from a dusky yellow to reddish brown and their undersides are usually a light yellow.
The turtle shows sexual dimorphism at maturity where the males have broader heads, longer claws and a longer tail with a flatter shell that the females. The loggerheads have a gland behind the eye known as the lachrymal glad which helps it eliminate the excess salt in its system but gives a false impression that the turtle is crying when it comes on to land.They cannot retract their flippers or head into the shell.
The loggerheads are omnivores throughout their life and are thought to have the widest feeding range. They too, like the leatherbacks have a cosmopolitan global distribution and cover a larger total geographical area than the leatherbacks.
They lay clusters of 100-120 eggs and re-nest about four times at fortnightly intervals and return to nest again after a period of 2-3 years.
The green turtles,also known as ‘GalKasbawa’ in Sinhala,get their name from the greenish fat found just under their shell which is due to the high amount of plant matter which they consume and not due to their colour which ranges from a dark olive brown to a black. They start life as carnivores and as they grow, become omnivores and by maturity most are strictly herbivores. They feed off the top part of ocean grasses, keeping the grass healthy and thus maintaining the health of the ecological habitat amongst the ocean grass beds.
They have been the subject of poaching, exploitation, pollution and accidental entrapment and are now on the endangered list.
On average they weigh 70-190 kg and are 1.5 m in length and distributed mainly in tropical and subtropical waters.
They also lay clusters of 100-120 eggs and re-nest about four times at fortnightly intervals and return to nest again after a period of 2-3 years and their nesting sites are under protection by the law in most countries.
Known as the 'PothuKasbawa' in Sinhala, it stands distinct from other sea turtles thanks to its narrow beak and long head which it uses to remove sponges between ridges on the reef which it feeds on. They also feed on Jellyfish. Their average weight is 80kg in and are about 1 metre in length.
These turtles are considered to be critically endangered due entrapment of turtles in fishing nets, loss of nesting sites, predation, pollution and the fact that their shells were used extensively for decorative purposes and sold as tortoise shells since ancient times. These turtles are now aggressively protected under international laws. Import, export and trade of products belonging to this species is banned.
They lay clusters of 130-150 eggs and re-nest about four times at fortnightly intervals and return to nest again after a period of 3-4 years.
Known as the 'MadaKasbawa' in Sinhala, they are the smallest of the turtles usually seen in Sri Lanka with an average weight of 35kg and a length of 65cm. They are olive green in colour and adults exhibit sexual dimorphism with males having longer tails and claws than the females.
Though they were once known as the most abundant variety of turtle, they are now considered to be vulnerable. The reason being the harvesting of adults for hides and the collection of eggs which are highly sought after worldwide as a delicacy.
They lay clusters of 80-120 eggs and re-nest 2-3 times at 3-4 week intervals and return to nest again after a period of 1 year.