Several animal species have been threatened by record-low temperatures in Texas this week, including about 3,500 sea turtles that were rescued and brought to the relative safety of dry land.

In cold temperatures, turtles can fall victim to a condition called a “cold stun,” when their body temperatures fall so low that they lose their ability to swim, eat or even hold their head above water.

“You could put a cold-stunned turtle in a half an inch of water and they’d drown,” said Wendy Knight, executive director of Sea Turtle Inc., a nonprofit group in South Padre Island, Texas, that is helping keep the turtles safe until they can return to the water.

Turtles that have been rescued by people on beaches or in boats are being put on plastic-covered pallets and allowed to warm for several days in the South Padre Island Convention Center.

Other animals in Texas have also been affected by the storm. A primate sanctuary in North Bexar County reported the cold-related deaths of a chimpanzee, several monkeys, lemurs and tropical birds, according to the San Antonio Express-News. And the El Paso Zoo found and rehabilitated a frigate — a type of sea bird — after it was blown off course.

Knight said the scale of the cold stun event for sea turtles was the largest in decades and could have a population-level impact. According to the U.S. Fish and Wildlife Service, five sea turtle species found in Texas are listed under the Endangered Species Act as “endangered” or “threatened.”

Also at immediate risk are a few dozen turtles housed at the Sea Turtle headquarters, where most are being rehabilitated for injuries. The facility is approaching its third day without power.