AnimaliaHighest rank in taxonomy. Groups all life into domains: Animalia, Plantae, Fungi, etc.IUCN VUInternational Union for Conservation of Nature — the world authority on species extinction risk, using standardized criteria. — Vulnerable — at high risk of extinction if the current adverse conditions continue.In ProgressCurrent stage of this record in the editorial review workflow. Recent Sighting
Lepidochelys olivacea
Olive Ridley Turtle
Eschscholtz, 1829
Detailed Texts Multi-lang
The olive ridley sea turtle (Lepidochelys olivacea) is the second smallest sea turtle in the world, surpassed only by the Kemp's ridley (Lepidochelys kempii), and is currently the most abundant sea turtle species on the planet. Its name derives from the dark olive-green color of its smooth, heart-shaped carapace. A distinctive taxonomic feature is that it possesses a variable and often asymmetrical number of costal scutes on its shell (usually 6 to 9 on each side), making it unique among sea turtles. It has a medium-sized head and jaws adapted for crushing. It is world-famous for its spectacular synchronized mass nesting reproductive behavior, known as an 'arribada'. Its distribution covers tropical and subtropical waters of the Pacific, Indian, and South Atlantic oceans. In Costa Rica, the beaches of Ostional and Nancite in the northern Pacific are biological sanctuaries of global importance, hosting some of the largest and most consistent arribadas of the species.
Added by
Anonymous Curator
Reviewed by
Under Review
Last modified by
Julia Trouin
TaxonomyBiological classification ranks placing this species within the tree of life, from Kingdom down to Genus.
PhylumRank below Kingdom. Groups organisms sharing a fundamental body plan (e.g., Chordata = vertebrates and some invertebrates).Chordata
ClassRank below Phylum. Subdivides by structural traits (e.g., Mammalia, Aves, Reptilia, Insecta).Reptilia
OrderRank below Class. Groups related families sharing common ancestry (e.g., Carnivora, Primates).Testudines
FamilyRank below Order. Groups closely related genera (e.g., Felidae = cats, Canidae = dogs).Cheloniidae
GenusRank just above Species. The first word in the two-part binomial scientific name.Lepidochelys
Taxonomic AuthorityThe scientist who first formally described and published this species, followed by the year of publication.Eschscholtz, 1829
Record Completeness
94%Coming soon
Ecology & StatusHow this species lives: habitat preferences, diet, behavior, population status, and role in its ecosystem.
OriginWhether the species is native (evolved here), endemic (found only here), or introduced by human activity.
Native
Population TrendDirection of change in population size over time: increasing, stable, decreasing, or unknown.
Decreasing
Breeding SeasonTime of year when this species typically reproduces or flowers.
--
Trophic RolePosition in the food chain: producer, herbivore, carnivore, omnivore, decomposer, or parasite.
Omnivore
Recent SightingsWhether this species has been observed in the wild in Costa Rica within recent years.
Yes
Habitat SummaryOverview of the specific ecosystems and environments where this species is found in Costa Rica. Multi-lang
It is a predominantly pelagic (open ocean) species, spending most of its life foraging in the water column at great depths or drifting in surface ocean currents. It occasionally inhabits benthic neritic (shallow coastal) zones. For nesting, it requires dark sand beaches with a gentle to moderate slope and tidal and current influences, conditions perfectly met on the Pacific coast of Costa Rica. They have a strong preference for areas with warm waters and high upwelling nutrient productivity.BehaviourDaily activity patterns, movement, territory use, foraging style, and seasonal behavioral changes. Multi-lang
They are highly migratory turtles that travel thousands of kilometers across the open ocean. They spend the day feeding or basking on the water's surface (to absorb heat and allow birds to remove their parasites). They communicate mainly visually and chemically, lacking complex interactions. Although they spend most of the year solitary and dispersed throughout the ocean, females gather in a coordinated manner off nesting beaches. They remain floating in 'flotillas' at sea for weeks before synchronized nesting. Newborn hatchlings emerge almost simultaneously at night to avoid desiccation from the scorching sun and minimize visual predation.Social ActivitySocial structure: whether the species is solitary, paired, or colonial; hierarchy and communication. Multi-lang
Lacks a complex social structure. Its life is characterized by solitary pelagic foraging for most of the year. However, its nesting behavior (arribada) represents one of the most massive aggregation events of any vertebrate. During the spawning season, hundreds of thousands of individuals communicate through shared environmental cues (not directly with each other) to gather in very specific zones. Despite the extreme proximity on the beach, they show no parental care, defensive cooperation, or kin recognition.Feeding GuildWhat the species eats, how it forages or hunts, and its role as a consumer in the food web. Multi-lang
Opportunistic Omnivore/Carnivore (Benthic and Pelagic). The olive ridley possesses strong, beak-like jaws perfectly adapted for crushing hard shells. They feed by diving to the seabed to crush crabs, shrimp, lobsters, and snails. When in the open ocean, they supplement their diet by hunting jellyfish, tunicates, salps, fish eggs, and even macroalgae, showing great dietary plasticity depending on prey availability.Trophic Chain DetailsSpecific interactions in local food webs: prey species, predators, competitors, and scavengers. Multi-lang
It is a carnivore and omnivore with a key role as a consumer of jellyfish, tunicates, and benthic crustaceans, helping control marine invertebrate populations. Adults are preyed upon only by large sharks (like the tiger shark) and orcas in the open ocean, and by jaguars on beaches. Eggs form the staple diet of thousands of coastal organisms on beaches like Ostional, serving as a massive influx of nutrients for bacteria, fungi, beetles, crabs, seabirds, coatis (Nasua narica), raccoons, and feral pigs. Mortality of eggs and hatchlings is exceedingly high, but the arribadas ensure a portion survives to reach the sea, where they face predatory fish and birds.Reproductive BehaviourMating strategies, courtship displays, nesting or spawning behavior, and parental care. Multi-lang
During the arribada (which occurs once or twice a month in the rainy season in Costa Rica), females frantically emerge from the sea at dusk, covering the entire beach of Ostional or Nancite. Each digs a nest with her rear flippers, deposits an average of 105 spherical, soft eggs, covers the hole, and returns to the sea, all in less than an hour. The sex of the hatchling is determined by temperature (high temperatures generate females). Incubation lasts about 45 to 55 days. Upon hatching at night, the tiny 4 cm hatchlings must run a deadly marathon to the sea guided by the reflection of the stars and moon on the ocean, dodging hundreds of predators.Physical Measures
Length (cm)
60.0 - 75.0 cm
Weight (Grams)
35.00 kg - 50.00 kg
Offspring per cycleTypical number of young (live births, eggs, or seeds) produced by one adult in a single reproductive event or breeding season.90 - 115
Sexual DimorphismObservable physical differences between males and females of the same species (e.g., size, coloration, features).Yes
Lifespan
Sexual MaturityAge at which the individual becomes capable of reproducing for the first time.
13 - 15 Years
Gestation / IncubationDuration from fertilization to birth (mammals) or to hatching (egg-laying species).
45 - 55
Lifespan EstimatedExpected duration of life from birth to natural death under wild conditions.
Males30 - 50 Years
Females30 - 50 Years
Sexual DimorphismPhysical differences in size, coloration, or morphology between males and females of this species.
Males Multi-lang
Adult males maintain the same size and coloration as females, but develop a significantly thicker and longer tail that extends beyond the posterior carapace (used to accommodate the copulatory organ). The carapace has a slightly flatter and more hydrodynamic profile. They possess a single visibly larger and curved claw on the leading edge of each front flipper, a critical tool they use to grip strongly onto the edge of the female's carapace to stay coupled during copulation amidst the strong ocean swell.
Females Multi-lang
Adult females have a short, flattened tail that is barely visible beneath the posterior margin of the carapace. They lack the enlarged claw on the front flippers that males possess. Their most characteristic feature is that the upper carapace is higher and strongly domed, an evolutionary adaptation that provides greater volume and space in the internal body cavity, strictly necessary to simultaneously house and mature a large volume of eggs (over 100) prior to their arribada.
Evolutionary AdaptationsInherited traits and behaviors that improve the species' survival and reproduction in its specific environment. Multi-lang
'Arribada' survival strategy (Predator swamping): The most extraordinary evolutionary adaptation of this species is its nesting method. Thousands, or even hundreds of thousands, of turtles emerge simultaneously from the ocean over a few days and nights. By flooding the beach with adult females, millions of eggs, and later millions of hatchlings emerging at once, they overwhelm the consumption capacity of local predators (jaguars, coatis, birds, crabs, and fish). It is mathematically impossible for predators to eat everything, ensuring a percentage survives.
Pelagic diving capability: Unlike the green turtle which feeds in shallow coastal waters, the olive ridley is highly adapted for deep-water diving (up to 150 meters) in search of benthic invertebrates. Its blood and muscle tissue contain high concentrations of myoglobin, allowing it to store extra oxygen and withstand the frigid temperatures of the ocean floor.
Main ThreatsDocumented pressures reducing the population: habitat loss, hunting, disease, climate change, and invasive species. Multi-lang
Incidental capture in trawl nets and longlines: By actively foraging for shrimp and fish, and by aggregating massively near the coast before arribadas, thousands drown caught in the nets of trawling vessels (industrial shrimp fishing) and on longline hooks.
Ocean plastic pollution: They are highly susceptible to ingesting ocean debris, particularly pieces of ghost nets, plastic bags, and microplastics that concentrate in oceanic convergence zones where olive ridleys spend much of their pelagic stage, causing digestive obstruction and death.
Interesting FactsSurprising or notable facts that highlight what makes this species unique or ecologically important. Multi-lang
The Ostional National Wildlife Refuge in Costa Rica is famous for having one of the only legal turtle egg harvesting programs in the world. Due to the destructive nature of the arribada, turtles arriving later often dig up and destroy the eggs of turtles that arrived earlier. Therefore, under strict biological control, the local community is allowed to legally extract and commercialize the eggs laid during the first hours of the arribada, a model of sustainable use that protects the rest of the nesting and benefits the local economy.
The triggers for a massive arribada remain a partial scientific mystery, but they appear to be strongly synchronized with lunar phases (especially the last quarter), high tides, and strong offshore winds. An arribada in Ostional can last from 3 to 7 days and involve up to 500,000 turtles.