The fearsome weapon above was used in the mid-19th c. by natives of the Gilbert Islands (now part of Kiribati) in the South Pacific. In addition to using sharks for household items and food, the islanders would edge swords, spears, and daggers with their razor-like teeth, attaching them with coconut fiber, human hair, and stingray skin. The historic weapons had been languishing in the collections of Chicago's Field Museum of Natural History until Columbia University biologist Joshua Drew and his colleagues decided to identify which shark species had been used. They cataloged 17 species and determined that 2 of them—the spotfin shark and the dusky shark—are no longer found in the local reefs. Remarked Drew, "Had we never done this work, nobody would have ever known that these things ever existed there. It had been erased from our collective memories that these sharks once plied these waters."