NEVADA STATE MUSEUM & HISTORICAL SOCIETY BIOLOGY GALLERY - Plants, Animals, and People In the Biology Gallery, see Mojave Desert cacti, safe to look at in exhibit cases.   Animals like the Bighorn Sheep, the Desert Tortoise, and butterflies and moths can be seen throughout the gallery.  The Spring Mountain exhibit goes from the valley's desert floor landscape up the mountains showing the different communities of plants and animals at different elevations.   A series of miniature dioramas depict the habitats of Nevada mammals from throughout the state.   Desert Bighorn Sheep   Anasazi (Ancestral Puebloan) Exhibit The story of the people who survived in the Las Vegas valley for two thousand years is told through pictures, text, and the tools and objects of daily life.  You can see the lifestyle and foods of these early Americans who  made their living in the deserts of southern Nevada.