The colorful sea slug known as Chromodoris reticulata (center image) boasts the ultimate throwaway culture. Researchers report online today in Biology Letters that the animal, found in the Pacific and Indian oceans, sloughs off its penis after sex (left)—then grows a new one. Scuba-diving researchers collected slugs from a coral reef off the coast of Okinawa, Japan, then watched as the animals mated in a tank (right). The animals shed their outer male organs 15 to 30 minutes after mating, but they were equipped for love again after roughly 24 hours. This is the first known case of copulation with what the researchers call a "disposable" penis. Dissection revealed a coiled and compressed stretch of reproductive tissue inside the slug's body. The researchers think this tissue elongates into a new penis, allowing a superstud slug to have as many as three hookups in 3 days. Good news for the slugs, and for those of us who remember the 90s .
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