1) Why do small mammals (eg, gophers, rats, mice, shrews) generally have a better fossil record than large mammals (eg. elephant, rhinos, horses)? 2) What is the common name for Mylagaulus? What do they look like? 3) What is the probable reason that the large Pleistocene mammals (eg. Mastodon, Mammoth, giant ground sloth) disappeared from Oregon 11,000 years ago?.