Human evolution and paleoanthropology are tricky subjects, not just because of the rarity of these fossils, but also because human nature seems to be getting in the way of modern taxonomy. In a field that is generally governed by logical rules when it comes to identifying new fossils, scientists are noticed there are some peculiarities applied to our own genus, Homo.

Between Utah and Colorado, there is a geographical diamond in which lies a rich collection of fossils and dinosaur footprints recording the history of when dinosaurs inhabited this region. All major ages of dinosaur life are recorded here, and for more than a hundred years, paleontologists have busily been debating which dinosaurs existed based on bones and abundant dinosaur tracks, the latter of which provide clues that allow geoscientists to interpret dinosaur daily life.

While expanding a reservoir in Snowmass Village, Colorado, workers stumbled upon a big bone. And then another, and another, and another. Realizing they found something special, the workers called in the experts at the Denver Museum of Nature & Science (DMNS), who drove several hours to examine the site. Scientists quickly realized that this was no ordinary boneyard. Work on the reservoir halted, as DMNS scientists called in dozens of volunteers and experts from around the country to help excavate the site before construction continued. In a few weeks of excavating, the scientists and volunteers of the Snowmastodon Project uncovered an entire Pleistocene ecosystem, including fossils of giant ground sloths, long-horned bison, North American camels, mammoths, mastodons, insects and ancient plants.

In a Utah cave, paleontologists are exploring the fossil record preserved in owl pellets since the Pleistocene glaciation. The fossils in the pellets are giving the scientists a glimpse of how the ecosystems have changed over time both from natural variation and more recent changes brought on by human settlement.