In mid-September, a sea turtle crawled out of the surf in southern California one evening and began laying eggs in the sand, the first time any sea turtle has been recorded nesting on the US west coast.
Beachgoers on Huntington Beach were stunned, and so were scientists. "This is the first documented case of a turtle nesting on the west coast," said Justin Viezbicke, California stranding coordinator for the National Oceanic and Atmospheric Association (NOAA). Days earlier, another olive ridley sea turtle had nested nearby at Seal Beach. Researchers first suspected the same turtle had traveled between the two beaches, but photos of shell shape and barnacle patterns confirmed two separate turtles were involved.
Olive ridley turtles normally nest far to the south, in Mexico and Central America. What pushed them hundreds of miles north is, in Viezbicke's words, "the million dollar question." Scientists are weighing several explanations: unusually warm coastal waters, the effects of El Nino, or a hurricane that hit the region that month, which may have blown the turtles off course.
It could also be an early sign of something bigger. Lance Adams, a veterinarian at the Aquarium of the Pacific, said the nests might mark the start of a broader northward shift as the turtles' native waters keep warming. That shift carries its own risk: egg temperature determines a turtle's sex, and above about 87.8F almost all hatchlings turn out female. A cooler, more northern nesting range could help keep populations balanced, though Adams cautioned that two sightings are not enough to draw firm conclusions.
The nests are now fenced off, but officials can only do so much. The eggs take 45 to 60 days to hatch, and coyotes, curious beachgoers, and storm surges could all threaten them before then.
Anyone who spots a turtle should stay at least 50 feet away and call a lifeguard or NOAA's stranding hotline rather than approach, Adams said.
The turtles are not the only unusual visitors drawn north by warming waters. Sharks, rays, seahorses, and venomous yellow-bellied sea snakes have all turned up on California beaches in recent years. As Adams put it, people may simply need to get used to sharing the coast with new neighbors.