In a cave in Australia, researchers from the University of New South Wales discovered giant fossilized sperm. The sperm were produced 17 million years ago by a group of tiny, shelled crustaceans called ostracods, making them the oldest fossilized sperm ever found. The results were published recently in Proceedings of the Royal Society B. The fossils were excavated in 1988, but it wasn’t known they contained sperm until they were studied in detail by an ostracod expert last year.