After the extinction of the dinosaurs, approximately 66 million years ago, the rise of mammals begun. There were mammals on earth before that date, but after the Cretaceous–Paleogene (K–Pg) extinction event (a mass extinction of some three-quarters of the plant and animal species on Earth—including all non-avian dinosaurs), mammals took over the medium- to large-sized ecological niches.
Some of them reached enormous sizes, usually they were larger than today’s counterparts (with the exception of whales). Here are some of the largest known prehistoric mammals.
Continue reading Largest prehistoric mammals