Classroom lesson · Wildlife · 🇸🇹 São Tomé and Príncipe

Green Sea Turtles

Ancient ocean travellers that return to the same beaches to nest

A green sea turtle swimming just below the surface of clear blue water

Photo · Wikimedia Commons

What is it?

Green sea turtles are large, graceful reptiles that spend almost their entire lives in the ocean - but the females come ashore every few years to lay their eggs on the same beaches where they were born. The quiet beaches of São Tomé and Príncipe are among the most important nesting sites for these turtles in the whole of West Africa.

Tell me more

Green sea turtles get their name not from the colour of their shell (which is usually brown or olive), but from the greenish colour of their fat, which comes from the sea grasses and algae they eat. They are powerful swimmers with large flippers that sweep them through the water almost like wings.

Every few years, a female green sea turtle makes a remarkable journey - sometimes thousands of kilometres across the ocean - back to the very beach where she was born. She crawls ashore at night, digs a hole in the sand with her back flippers, lays around 100 eggs, covers them up, and returns to the sea. She may do this several times in one season.

The eggs incubate in the warm sand for about two months. When the tiny hatchlings are ready, they dig upward through the sand and scramble toward the sea - usually at night, guided by the brightness of the open horizon over the water. Many local people feel a great pride and responsibility for looking after the nesting beaches.

The beaches of São Tomé and Príncipe are carefully monitored during nesting season. Community members and scientists work together to count nests and make sure the turtles are not disturbed. The turtles have been swimming these waters for millions of years - they are living links to prehistoric times.

In the classroom

Walk your class through this in 15 minutes.

Talk together

Discussion prompts

  1. 01A sea turtle travels thousands of kilometres back to the beach where it was born. How do you think it knows which beach to return to?
  2. 02The hatchlings head toward the light of the open horizon. What could happen if beaches have too many bright electric lights nearby?
  3. 03Why might local communities on São Tomé feel proud to protect the nesting turtles on their beaches?
  4. 04Green sea turtles have survived for over 100 million years. What does that tell us about them?
Try this

Classroom activity

Map the life journey of a green sea turtle. Draw the turtle's path from hatching on a São Tomé beach, through years of ocean swimming, and then back to the same beach to nest. Mark the ocean in between. Write one sentence for each stage of the journey explaining what the turtle is doing and why.