Sea Turtles — by Shekar Dattatri
About the Author
Shekar Dattatri is a well-known writer who writes popular articles on wildlife, conservation, and filmmaking. He has been interested in nature since childhood and is an award-winning wildlife and conservation filmmaker. His work focuses on raising awareness about India's rich biodiversity and the need to protect endangered species.
Summary of the Lesson
The lesson "Sea Turtles" introduces students to the fascinating world of marine turtles, their life cycle, and the conservation challenges they face. It begins by distinguishing sea turtles from their land-dwelling relatives, tortoises, and explains that sea turtles spend almost their entire life in the sea. There are seven species of sea turtles worldwide, and five of them — the Olive Ridley, the Hawksbill, the Green Sea Turtle, the Loggerhead, and the Leatherback — are found in India's coastal waters. The Olive Ridley is the smallest (up to 35 kg), while the Leatherback is the largest, growing up to 2.2 metres in length and weighing as much as 700 kg.
The lesson describes in detail the egg-laying process of the Olive Ridley turtle. Between January and March, female turtles come ashore at night, haul themselves laboriously onto the beach using their flippers, scoop out a nest cavity about 45 cm deep, and lay around 100 eggs (each the size of a table tennis ball). After laying, the turtle camouflages the nest by tossing sand on it and returns to the sea, leaving the eggs to incubate under the warmth of the sun. A special phenomenon called Arribada (mass nesting) takes place in Odisha, which is one of only three places in the world where thousands of female turtles come ashore simultaneously to nest.
The hatchlings emerge after 45–60 days, using a tiny 'egg-tooth' to slash open the leathery eggshell. They push through the sand and make a hurried dash to the sea. However, survival is extremely difficult — only about one in every thousand hatchlings survives to adulthood. They face threats from crabs, birds, and other sea predators. Interestingly, the temperature inside the egg determines the sex of the embryo: 27–28°C produces males, 30°C produces females, and precisely 29–30°C produces an equal mix. After many years, adult females return to the same beach where they were born to lay their own eggs. The lesson concludes by highlighting the threats from human activities — hunting, egg collection, pollution, plastic waste, and coastal construction — and urges the need for systematic conservation efforts.
Glossary
| Word | Meaning |
|---|---|
| Marine | Found in the sea |
| Species | A group of animals with common features |
| Coastal | Land by the edge of a sea |
| Flippers | Broad, flat limbs used for swimming |
| Haul | Pull with great force |
| Laboriously | With great effort |
| Cavity | A hollow space |
| Camouflage | Hide or disguise something |
| Incubate | Hatch eggs using warmth |
| Predators | Animals that kill other animals for food |
| Hatchlings | Young animals that have just come out of their eggs |
| Slash | Cut |
| Snout | Pointed nose of an animal |
| Emerge | Come out |
| Mysteries | Facts that are difficult to understand |
| Fascinating | Attracting greatly |
| Decade | A period of ten years |
| Survive | Continue to live |
| Arribada | Mass nesting event where thousands of turtles nest simultaneously |
Themes Covered
- Marine Biology: Introduction to sea turtle species, their physical characteristics, and life cycle
- Reproduction and Life Cycle: Egg-laying behaviour, incubation, hatching process, and survival rates
- Wildlife Conservation: Threats from human activities and the urgent need to protect sea turtles
- India's Biodiversity: Five species of sea turtles found in Indian coastal waters and the Arribada phenomenon in Odisha
- Environmental Awareness: Impact of pollution, plastic waste, and coastal construction on marine life
- Scientific Curiosity: Temperature-dependent sex determination and the mystery of how turtles navigate back to their birth beach