Green Sea Turtle & Costa Rica

Although hatchling and juvenile green turtles are omnivorous, adult green turtles are the only fully herbivorous species among sea turtles. This species owe their name to the green hue their fat acquires from their plant-based diet, despite their primarily brown skin and carapace.

Historically, green turtle meat and eggs were vital protein sources for pre-Columbian peoples across the Americas. Their meat and fat also became prized delicacies among European aristocrats and were essential for sustaining nutrient-starved Conquistador sailors during European colonization.

However, unregulated harvesting and increased demand for green turtle products led to the extinction of green turtle populations in several Caribbean islands, pushing the species to the brink of extinction. Fortunately, Tortuguero, formerly known as the Turtle Bogue, emerged as a stronghold for Caribbean green turtles. Located in northeast Costa Rica, it became one of the last refuges for these graceful creatures as awareness grew about their conservation status.

Over the past 50 years, Tortuguero has seen a significant recovery in the green turtle population. Today, it proudly hosts the largest nesting population in the Atlantic Ocean, with approximately 100,000 green turtle nests and over 8 million hatchlings produced annually. Consequently, it remains the most abundant sea turtle species in Turtle Love’s research area.

In essence, green turtles embody resilience in the face of adversity. Despite the challenges posed by overharvesting and habitat loss, Tortuguero’s success story underscores the importance of conservation efforts. Through continued research and dedicated initiatives, we can ensure the survival of green turtles for future generations.

Scientific name

Chelonia mydas

Common names

English: Green turtle and Greenback turtle

Spanish: Tortuga Verde, Tortuga Blanca, Tortuga prieta

Portuguese: Tartaruga verde and Aruanã

Size and weight
Adult green turtles measure between 80 and 130 cm (30 to 50 in) in curved carapace length and weigh between 100 and 250 kg (220 to 550 lbs).

Green Sea Turtle Population

Green turtles inhabit tropical waters worldwide, with the Caribbean coast of Costa Rica standing out as the primary nesting area for this species in the Atlantic. Globally, it ranks second only to the green turtle population nesting in Australia. For more detailed information on the location of nesting beaches and foraging areas, refer to the SWOT map.

Reproduction

Female green turtles typically reproduce every two to three years, while males may do so annually. Each green turtle nest contains approximately 110 eggs, and on average, a female lays six nests per season. A 10 to 14-day interval between nests is customary for green turtles. Following nesting in Costa Rica, green turtles typically migrate north to Nicaragua, where their primary foraging grounds are located off the Miskito Cays.

Diet

The green turtle is the only fully herbivorous species among all seven sea turtle species, with its diet varying throughout its distribution range and life stages. While young green turtles are omnivorous, consuming both plant and animal-based food, they transition to a strictly herbivorous diet as they mature, primarily feeding on algae and seagrass.

Alike other vertebrates, green turtles lack specialized microbiota to digest the cellulose and lignin found in plant cells. Therefore, they rely on hindgut fermentation, a process similar to that of horses, to extract nutrients from plants. In the Caribbean Sea, green turtles predominantly feed on turtle grass (Thalassia testudinum), which forms a significant portion of their diet. This adaptation allows green turtles to thrive in their coastal habitat while fulfilling their nutritional needs solely from plant sources.

Identifying features

Color

Contrary to what their name might suggest, green turtles are primarily brown in color. Their name originates from the green hue of their fat, a result of their herbivorous diet.

Hatchling green turtles exhibit countershading, a common adaptation among species dwelling in the ocean’s water column. They possess a dark upper body and a white underside, aiding in their evasion of predators from both below, such as sharks, and above, such as seabirds. This coloration provides them with effective camouflage, helping them to blend into their surroundings and avoid detection.

Scales

Green turtles are characterized by four pairs of lateral scutes on their shells. Additionally, they possess a pair of pre-frontal scales located between their eyes, along with four preocular scales situated behind the eyes. These distinct features contribute to the identification and classification of green turtles within the broader spectrum of sea turtle species.

Conservation status

Green turtles are listed as globally Endangered by the IUCN Red List of Threatened Species. This is also the conservation status of the Northwest Atlantic Subpopulation of green turtles, which includes green turtles nesting at Turtle Love’s project site.