What do horseshoe crab eat? Horseshoe crabs feed on mainly insect larvae, worm, mollusks and sometimes small fish and crabs. How do I distinguish male and female horseshoe crab? In general, female horseshoe crabs are larger in size than male horseshoe crabs. Also, the mature male horseshoe crab will develop a modified first pair of … Continue reading Horseshoe crabs: Q&As