Strange “snake skeletons” recently found coiled up on Outer Banks beaches have been identified not as animal remains, but as egg casings, according to the National Park Service.
What kind of animal lays eggs in the shape of a snake?
“These egg cases are laid by the Whelk..., a sea snail that eats crabs and other mollusks,” according to a Cape Hatteras National Seashore Facebook post. “Each small compartment of the casing can house 20-100 eggs and on average can reach 3 feet long!”
Park officials shared a photo of one of the casings, and it looked pretty much like a snake vertebrae, slithering across the beach.
Fall is among the times of year the casings are most apt to wash up, because it’s when whelks lay eggs, officials say. (Whelks also lay eggs in the spring, officials said.)
“I remember our first visit ever (to the Outer Banks) and seeing these on the beaches,” posted Tammi Bazyn Steffen on Facebook. “They freaked me out because they look like a spine... I didn’t go near it.”
The casings have long mystified beachgoers, resulting in centuries of odd interpretations. Among the many names folks used for the casings are “mermaid’s necklace” and ”fisherman’s soap,” park officials said.
“Females will lay a string of eggs in deep water twice a year and the babies will hatch out of the casing anywhere from 3 to 13 months,” the park posted.
The strangely shaped whelk egg casings provide much needed protection from predators as the drifting eggs mature, according to Acaquarium.com.
Commenters on the park’s Facebook post noted they had found whelk casings with the young still trapped inside. But in most cases, the “leathery” strands wash up after “the tiny whelks have already hatched and crawled away,” according to Tybeemarinescience.org.
“When whelk eggs hatch inside the capsules, the tiny whelks cannibalize each other before eating their way out of the casing,” Tybee Marine Science says.
Cape Hatteras National Seashore posted its explanation for the egg casings not long after warning visitors they could find all types of things exposed on beaches by the passing of Hurricane Dorian.