Oxydactylus
Let’s look at some of the individuals and small groups that are moving or resting within view. The camels with the very slender legs and long necks are called Oxydactylus (“sharp finger”). They are browsing on the willows where the herd of Nanotragulus ran to hide. Oxydactylus is an important camel, standing about at the midpoint in the evolution of this North American family of mammals. The camels will remain stay-at-homes in the continent of their origin until they spread into Eurasia and South America at the beginning of the Pleistocene Epoch, some 17.5 million years after the rhinos died out at Agate. There are many species of Oxydactylus; the one we are looking at stands about 1.2 meters (4 feet) high at the shoulder. Notice that they don’t have humps on their backs; in this lush land there is no need to store fat against a time of possible starvation.
Stenomylus
Speaking of camels, here comes a herd of Stenomylus (“narrow tooth”) bounding through the tall grass on the south bank of the river. This is a strange little long-neck camel that strayed off the main line of the family’s evolution. Less than 60 centimeters (24 inches) high at the shoulder, it looks very much like the living African antelope called the gerenuk. Stenomylus, with its long and delicate legs and tall cheek-teeth, is perfectly adapted for living in and eating the abundant grass which billows on this tree-dotted plain. Yet many of the little Stenomylus are going to share a tragic time with hundreds of Menoceras only a year or so from this day we are visiting. Later, we’ll move ahead to that time so you can see that natural disaster, now preserved in rock, as it happened.
When you travel back 20 million years in time you would expect to find unbelievably bizarre animals. So far, we’ve seen some offbeat specimens, but there has been nothing really out of this world. Now, if you look to the north by the lone oak tree, you will see a real prize. Do you see that hulk stepping out of the shade? No, it isn’t the Dragon of the Ishtar Gate, though it might pass for a mythical beast. What a wonderful animal! A head like a large horse’s, a neck somewhat slimmer, long front legs, sloping back, short hind legs, and a little switch tail. Watch with your field glasses when it moves out onto the bare ground. See the feet? They don’t have hooves; each toe ends in a great curved claw! This is one of the fabulous chalicotheres, a relative of the horses and the rhinos. There were never very many of them living at one time, but the family lived in Eurasia from the Eocene, some 55 million years ago, through the Pleistocene; and here in North America from the Late Eocene to the Middle Miocene.
Moropus
This chalicothere is named Moropus (“sloth foot”), and it is little wonder that when paleontologists first discovered his foot bones (without an associated skull) they thought they had found the feet of a ground sloth. Let’s watch Moropus as it ambles slowly across the plain, its strange stilted walk a little like that of the modern giraffe. Other animals move aside as Moropus strides through the grass. He’s a browser, an occasional grass-eater, and even a digger of easily accessible roots and tubers. Like his cousins the rhinos, he isn’t at all bright, and he has a very short temper. When he’s annoyed, he kicks out with those claws and every animal with good sense leaves him alone. He’s respected by meat-eaters and plant-eaters alike. He walks by himself and everything else detours around him.
