Free Pass Fridays Answer: Jan. 18

The blood of horseshoe crabs is used to ensure that pharmaceutical and medical devices like intravenous drugs and vaccines are free of bacterial contamination. Luckily, scientist can remove some of the horseshoe crab's blood and then return the animal back to the water. The crab's blood levels rebound in about a week. To learn more, check out the Ecological Research and Development Group's website.