Coming across an animal skeleton in the wild will stop anyone in their tracks with awe and wonder. But when marine biologist Madison McKay saw a purple skeleton while exploring some California tide pools, she knew it was a “bucket list” find.
McKay shared the shocking discovery on Instagram with her followers, leaving viewers stunned to learn that not only is the creature a trippy color, it also belongs on the endangered species list.
“I could not be more excited! There’s bones everywhere!” she says, adding in the caption, “Seeing this almost complete skeleton was insane!!”
Finding a purple skeleton
In her video, McKay is clearly ecstatic as she comes across the purple skeleton. The post cycles through clips of McKay showing off a series of different bones (including a skull and long spine) from the animal, which have a “purple-pink hue.”
She explains that the color comes from the mammal’s diet, offering viewers a hint at what the animal is.
“If you guessed sea otter, you are correct!” she says. “Sea otters eat a wide variety of shellfish, but sometimes they specialize on a particular food source.”
The source? Purple sea urchins. “If that happens to be the source, their bones and teeth can turn purple,” McKay explains.
Why bones turn purple
McKay explains how a diet rich in purple sea urchins can slowly dye a sea otter’s bones. “Purple sea urchins are echinoderms, and they contain a pigment mostly in their spines and test (the sea urchin’s hard shell) called echinochrome,” she says. “The uptake of this pigment is called echinochrome staining.”
The California Department of Fish and Wildlife shares a short, downloadable infographic explaining that this can happen to sea otters only after years of eating purple sea urchins. From that, the pigment accumulates in the sea otter’s tissues. The purple color can impact as little as one or two teeth or the entire skeleton.
Now, if you’re wondering whether human bones can turn purple from eating purple sea urchins, the answer is no. McKay explains in another video that since humans don’t eat the part of the sea urchin with the pigment (the spikes and test), it’s not possible.
However, McKay shares an interesting tidbit on that front: the part of the sea urchin humans do eat, called the “uni,” is actually the sea urchin’s gonads. Fun.
Sea otters are endangered
McKay notes that it is “pretty rare” to find an “intact” sea otter skeleton—and even “more special” to find a purple one. That’s because sea otters are protected under the Marine Mammal Protection Act of 1972, which made it “illegal to ‘take’ marine mammals without a permit, and later the Endangered Species Act.
According to The Otter Project, sea otters weren’t officially protected under the Endangered Species Act until 1977. The Center for Biological Diversity notes that sea otters once lived in various areas, from Baja California, Mexico, to Alaska. However, between 1741 and 1911, sea otters were hunted nearly to extinction because of the maritime fur trade. In California alone, sea otters were believed extinct until a small group was found near Big Sur in the early 20th century.
The protections sea otters are now under mean “it’s illegal to possess any part of a sea otter, including their bones,” shares McKay. “If you do come across something like this, the only thing you should take are pictures,” she concludes.
