Now for another weird and wonderful beast! Trotting daintily out of a thicket on our left is a herd of something you might think were deer or pronghorn. But if you look closely you’ll see that they have two pairs of curving, unbranched horns on their heads, not the single pair of prongs you’d expect on a pronghorn. These are _Syndyoceras_ (“together horn”), members of a family of mammals found only in North America and now extinct. Even on the Early Miocene day we’re visiting, they are scarce, moving only in small herds. The rear pair of horns is not remarkable, but the front ones, which rise from a large bump near the nose, curl up and away from each other, ending in blunt tips.
The first member of this family was _Protoceras_, which lived in the hills and mountains of western South Dakota during the Late Oligocene, just a few million years before the day we are visiting at Agate. Paleontologists have found battered scraps of its skeletons in the White River Badlands where perhaps they were washed by heavy spring rains running off the hills to the west. _Protoceras_ had six bony bumps on its head that presumably bore short horns; one pair was over the nose, another was over the eyes, and a third was near the back of the skull. Probably it was the direct ancestor of _Syndyoceras_.
If _Syndyoceras_ fails somehow to qualify as grotesque, let’s jump a few million years into the “future” and look at his Late Miocene descendant, _Synthetoceras_ (“combined horn”). Here was an animal on a par with unicorns and cyclopses. Like _Syndyoceras_ he had two tall horns at the back of his head; but something had happened to the curved ones on his nose. They had, during several million years of evolution, grown together into a single shaft and then spread out again to the sides and up. What a pity there were no little boys then, for here we have the world’s first and only self-propelled slingshot! Tie a rubber band to the tips of his nose horns, fill your pocket with pebbles, and saddle up.
You may be wondering by now about the smaller animals—the rodents and small carnivores. We have not seen any of them so far. Most carnivores work at night, but there should be a few about. Down by the river is a pair of _Oligobunis_ (“little cusp”) hunting near the water’s edge. They look something like modern badgers but are really more closely related to the weasels. If you look just to the right of the herd of _Stenomylus_ we were following earlier you might be able to catch a glimpse of a stalking cat about the size of a mountain lion. It’s probably either an advanced _Nimravus_ (“ancestral hunter”) or an early _Pseudaelurus_ (“false cat”), but we’ll have to get a closer look before we can be sure. Whichever it is, it’s on the main line of cat evolution and will eventually end up in our familiar _Felis_ and the other living cats. There should also be some sabretooth cats lurking about; they are found in nearby deposits of the same age, though not at Agate itself.