During the Late Pleistocene the sticky mud around Lake Callabonna in South Australia became a death trap for thirsty megafauna. One of the victims was the giant flightless bird Genyornis, the last of a lineage of big birds that was endemic to Australia. These birds were initially thought to be close relatives of emus and cassowaries, but examination of their fossil skulls has since suggested that they are closer cousins of chickens or waterfowl.