Living in the waters of the Atlantic coast, one prehistoric animal has played a key role in the fight against COVID-19.
The horseshoe crab is critical to the safety of human vaccines because its blood contains cells that the biomedical industry uses to test vaccines — including coronavirus jabs — to ensure they are not contaminated with bacteria.
They've existed for hundreds of millions of years. Having outlived the dinosaurs, horseshoe crabs face their ultimate challenge: humans. Loss of habitat and over-farming means that horseshoe crabs are now threatened with extinction.
"They haven't changed in 450 million years", says Laurel Sullivan, education coordinator at the Delaware Department of Natural Resources and Environmental Control's Coastal Programs."There's nothing about them to hurt us with, nothing threatening. They just live their lives."
But the discovery of their life-saving properties has given rise to a huge industry. More than half a million are caught along the United States' east shores every year.
Nevertheless, experts are holding out hope for the future of this life-saving living fossil.
"I think they will make it and they will survive", says Glenn Gauvry, president of the Ecological Research & Development Group.
"Other testing methods are being developed for medicine and fishermen can use other baits. So the animals are under less pressure."