Stingrays have a secret weapon. They have two stinging spines on their tail which can grow up to 13 centimeters long. These spines are connected to poison glands and can cause painful and dangerous wounds. According to legend, the Greek sea hero Odysseus was killed by a sting from the stingray. However, these animals were not only feared. They were highly desired by fishermen for the oil in the liver, which supposedly helped ease muscle aches. It was even said that fishermen would dipped their underwear in the oil in order to help withstand harsh weather conditions.