Like modern elephants, Columbian mammoths were probably social and lived in matriarchal (female-led) family groups; most of their other social behavior was also similar to that of modern elephants. This is supported by fossil assemblages such as the Dent Site in Colorado and the Waco Mammoth National Monument in Waco, Texas, where groups consisting entirely of female and juvenile Columbian mammoths have been found (implying female-led family groups). The latter assemblage includes 22 skeletons, with 15 individuals representing a herd of females and juveniles that died in a single event. The herd was originally proposed to have been killed by a flash flood, and the arrangement of some of the skeletons suggests that the females may have formed a defensive ring around the juveniles. In 2016, the herd was suggested to have died by drought near a diminishing watering hole; scavenging traces on the bones contradict rapid burial, and the absence of calves and the large diversity of other animal species found gathered at the site support this scenario. Another group, consisting of a bull and six females, was found at the same site; although both groups died between 64,000 and 73,000 years ago, whether they died in the same event is unknown. At the Murray Springs Clovis Site in Arizona, where several Columbian mammoth skeletons have been excavated, a trackway similar to that left by modern elephants leads to one of the skeletons. The mammoth may have made the trackway before it died, or another individual may have approached the dead or dying animal—similar to the way modern elephants guard dead relatives for several days.