Female caribou chew shed antlers to get calcium and phosphorus. These minerals help them produce milk after giving birth.

Learn how the answer behind why female caribou have antlers lies in how shed antlers provide a nutritional lifeline to a famous migratory group of Arctic caribous.

Female bees and wasps are the real defenders. Only females can sting, because stingers are modified egg-laying organs. Males do nothing in defence. Females guard nests, food, and colonies with extreme ...