In 1983, paleontologists gave an odd, now-extinct cousin of the wildebeest the name Rusingoryx atopocranion (Greek for “the strange-skulled antelope from Rusinga”). But at the time, they had no idea how strange the beast truly was. Turns out, it had an S-shaped tube in its skull—a feature known from no other mammal, living or extinct—that may have allowed it to bellow at unusually low frequencies. The finding, reported online today in Current Biology, comes from CT scans of several more-complete skulls of the species (artist’s concept, above) also unearthed on Kenya’s Rusinga Island, a near-shore landmass in the northeastern corner of Africa’s Lake Victoria. The newly described fossils, entombed in sediments deposited on a floodplain sometime between 40,000 and 285,000 years ago, include the skulls of both adults (which are about the same size as today’s wildebeest) and juveniles. Using computer analyses, researchers suggest that airflow through the bony tube would have generated sound with a frequency somewhere between 248 and 746 cycles per second—a range that encompasses the droning tone of the South African vuvuzela, which became notorious during soccer matches held during the 2010 World Cup. Yet when soft tissues of the throat and windpipe are also considered, the tone could easily have dropped below 20 cycles per second, a frequency that most humans—and more importantly, most predators on the arid African savanna—couldn’t have heard. Besides helping the creature avoid predators, the low-frequency bellows (which could possibly have been heard 10 kilometers away) may have enabled herds to communicate surreptitiously with each other, or for males to attract females. The odd tube, although absent in all living animals, has been found inside the skull crests of certain species of dinosaurs—which also might have used the feature for low-frequency communication.