The horseshoe crab can still live after taking blood. The horseshoe crab has experienced four mass extinctions and is called a "living fossil" in the sea. Since its birth 406 million years ago, the horseshoe crab has experienced the Devonian mass extinction (365 million years ago), the Permian mass extinction ( 250 million years ago), the Triassic mass extinction (200 million years ago), and the Cretaceous mass extinction (65 million years ago).

Each horseshoe crab can receive 50 ml of blood. 50 ml of blood is necessary for There is almost no impact on the life safety of horseshoe crabs. They can recover within 7 days, but there are also 5%-20% of horseshoe crabs that die because their blood is drawn.