Ancient rhinos in Nebraska lived in large local herds and died slowly from volcanic ashfall, not sudden disaster. Credit: John Haxby/The University of Nebraska State Museum ************************************************************************* Volcanic eruption from 12 million years ago preserves a snapshot of extinct animal life. Rhinos that once roamed much of North America 12 million years ago likely lived in large herds, according to a new study by the University of Cincinnati. Researchers examined isotopes in the teeth of rhinos found in what is now northeast Nebraska. At this site, more than 100 rhinos died at a single water hole and were buried in...