Source checked by DailyFact editors
Horseshoe crabs are closer to spiders than crabs
Horseshoe crabs are more closely related to spiders and scorpions than to crabs.
Why it is true
They predate the dinosaurs by more than 200 million years. Their blue, copper-based blood clots around bacterial toxins, so medical researchers use it for testing.
Check the source
We keep the original reference beside the claim so you can inspect the evidence and surrounding context yourself.
Open NOAA Ocean Service
