Green Sea Turtle

Overview

The green sea turtle (Chelonia mydas) is the world’s most numerous hard-shelled marine turtle and — in Tortuguero — the reason this stretch of Caribbean coast became a national park. Adult greens are large (90–150 kg), strict herbivores as adults (seagrasses and algae), and famous for the breeding-migration loyalty that has them returning to the same nesting beach across decades.

The common name refers not to the carapace but to the greenish fat beneath it, a coloration absorbed from the algae diet.

Why Tortuguero

The 22-mile Tortuguero beach is the largest green-turtle nesting rookery in the western hemisphere. By the 1950s the rookery had been very nearly wiped out by industrial poaching. The recovery is one of the longer success stories in tropical conservation, anchored by the work of Dr Archie Carr and the Sea Turtle Conservancy (STC, founded 1959 in response to Carr’s The Windward Road). STC’s Tortuguero project is the longest continuously running sea-turtle monitoring program anywhere in the world.

In October 2025, the IUCN downlisted Chelonia mydas globally from Endangered to Least Concern, citing a 28% rise in monitored populations since the 1970s and ~538,000 clutches recorded worldwide in 2024. Tortuguero contributed materially to that recovery. Some local populations remain threatened (Mediterranean: Critically Endangered; eastern Pacific and Florida: Endangered) — the global LC tag does not mean the species is safe everywhere.

How to see them (honestly)

• Nesting: July–October, peak August. Authorized guided night-tours only; SINAC raffles 200 spots per night across 5 base points along the beach. Park rules are strict and worth knowing in advance — dark clothing, no flashlights, no flash photography, no scent (perfume, sunscreen, insect repellent all bother the turtles).
• Hatchlings: September–November. Best windows are dawn (5–6 AM) and late afternoon (4:30–5:30 PM) at the surf edge. No artificial light during nesting season — beach lights disorient both nesting females and the emerging hatchlings.
• At sea: adult greens forage in seagrass beds, occasionally surface near the river mouth. A boat tour at dawn can produce sightings.

Status note

The October 2025 IUCN reassessment is real but it’s species-level. The Tortuguero nesting population is regarded as recovered relative to its 1950s nadir but is still actively monitored: nest counts fluctuate, beach-erosion threats are ongoing, and the population is sensitive to light pollution and any return of large-scale take. Recovered and safe forever are not the same status.