After the extinction of non-avian dinosaurs at the end of the Cretaceous period, many mammals underwent a rapid increase in size. Several hypotheses for this change have been put forward, with much debate about the drivers. In new research, a team of scientists in Spain looked at the record of body size in brontotheres (thunder beasts), an extinct lineage of large herbivorous rhinoceros-like mammals (though more closely related to horses) from the...
