The sea turtle population champion in today’s oceans is the olive ridley sea turtle (Lepidochelys olivacea), a small, wide‑ranging turtle that still numbers in the millions despite major declines in the last century.wikipedia+2
Who the olive ridley is
Olive ridleys are one of the smallest sea turtles, with a roughly heart‑shaped shell and an olive‑green color that gives them their name.fisheries.noaa+1
They are also the most abundant sea turtle species globally, historically counted in the tens of millions, though their numbers have dropped by 30–50% from past levels.adfg.alaska+3
Why is the Olive ridley population larger than other species?
Where it lives
Olive ridleys live in warm tropical waters of the Pacific, Indian, and Atlantic Oceans, making them one of the most widely distributed sea turtles.seeturtles+2
They are primarily pelagic, spending much of their time in the open ocean, but they also use continental shelf waters, bays, and estuaries near coasts.wikipedia+1
This versatility has made it easier for Olive ridleys as a species to manage threats from one location to another.
Where it lays its eggs
Females come ashore on sandy tropical beaches to nest, often on just a few key beaches that host enormous nesting aggregations.fisheries.noaa+1
Some of the largest nesting sites are in Mexico, Costa Rica, Nicaragua, Panama, and parts of the eastern Atlantic and western Indian Ocean, where single beaches can host hundreds of thousands of nesting females in a season.wikipedia+1
This is another advantage the Olive ridley has over other species like the Kemps ridley, which only nests on specific beaches in the Gulf of Mexico.
photo by Dr Sandeep Das and Sanctuary Nature Foundation
The “arribada” phenomenon
Olive ridleys are famous for arribadas, mass nesting events where tens or even hundreds of thousands of females come ashore over just a few days.seeturtles+2
Beaches like La Escobilla in Mexico and Ostional and Nancite in Costa Rica can see hundreds of thousands of turtles nesting in synchronized waves, turning the sand almost completely gray‑green with shells.seeturtles+1
These arribadas are another characteristic that gives the Olive ridley a breeding advantage.
What the olive ridley eats
Olive ridleys are opportunistic omnivores, eating a mix of animals and plant material.wikipedia+1
Their diet includes jellyfish, shrimp, crabs, snails, fish, and sometimes algae or other marine plants, allowing them to exploit many different ocean habitats.seeturtles+1
How far they travel
Like other sea turtles, olive ridleys migrate between feeding grounds and nesting beaches, sometimes crossing entire ocean basins.ocean.si+2
Tracking studies of sea turtles show that individuals routinely travel hundreds to over a thousand miles between nesting and feeding areas, and olive ridleys likely match these long‑distance “commuter” patterns given their broad distribution.seaturtletrackers+2
Conservation status and threats
Despite being the most numerous sea turtle, olive ridleys are listed as threatened globally and endangered in some key breeding populations because of steep historical declines.oliveridleyproject+2
Major threats include entanglement in fishing gear, direct harvest of adults and eggs, and loss or disturbance of nesting beaches, especially at the few remaining large arribada sites.adfg.alaska+2
Other intriguing facts
- Olive ridleys can switch between solitary nesting and arribadas, an unusual flexibility among sea turtles.fisheries.noaa+1
- A single arribada beach can support hundreds of thousands of nesting females in a year, making these sites globally important “capitals” for the species.ocean.si+1
- Even with an estimated ~800,000–2,000,000 nesting females, their population today is far below historical levels, showing how vulnerable even an “abundant” marine species can be.oliveridleyproject+3