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Once upon a Time In Riverbluff Cave...
...tens of thousands of years ago, Missouri looked much different than it does today. We were in the middle of an Ice Age, and much of the earth was cold and covered by snow and ice. However, during periods when the glaciers covering the area diminished and melted---the interglacial stages of the Pleistocene (1.8 million to 11,000 years ago)--the climate of Missouri and the rest of the Midwest was actually warmer at times than it is today. During these interglacial stages an ecosystem characteristic of lower latitudes shifted northward, and Missouri became the home of such animals as the peccary, snakes and other reptiles, and even giant turtles. When the climate turned cooler with the onslaught of another glacial advance, Missouri's Pleistocene ecosystem shifted to that characteristic of a colder climate and a higher latitude.
Many animals from both the warm and cold periods used Riverbluff throughout the years. Most of the animal findings within the cave, please remember, probably did not live there at the same time. Because of the variance in animals represented, the fossils and tracks found within the cave are potentially anywhere from 1 million to ten thousand years old.
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The Short-Faced Bear (Artcodus Simus)
The short-faced bear was the single most deadly predator of the Ice Age. It was bigger than the polar and grizzly bears, twice their weight, more carnivorous, and at the top of the food chain. The short-faced bear had a short, sleek, and stealthy body, with long, powerful legs, a short face, and a broad powerful muzzle filled with large piercing canines and jagged molars that could tear through the toughest hides and crush the thickest bones, including those of a mammoth or mastodon.
As you can see from the image, the short-faced bear stood almost ten feet tall--much larger than both modern polar bears or grizzlies. (One set of claw marks inside Riverbluff show the bear that made them was standing at least 12 feet tall on his hind legs.) The giant short-faced bear was most likely a rather solitary scavenger or predator, except for mothers with cubs and during the mating period. Although it survived the end of the last glaciation, it could not compete with the invasion of both brown and grizzly bears into the modern habitat. (If you wonder how a smaller bear could push out the dominant short-faced bear, remember this: a brown bear weighs about 300 pounds; a good sized short-faced bear probably weighed about 1400 pounds--which would make it much harder to get around and to catch fast prey like the brown and grizzly bears could.)
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Peccary
Peccaries are members of the artiodactyl family Tayassuidae (pigs/boars). Peccaries can easily be distinguished by the fact that their tusks point downward. In true pigs the tusks curve upward. In addition, peccaries have less complex cheek teeth, reduced side toes, and large, dorsal musk glands.
Two species of peccary were present in North America north of Mexico 16,000 years ago, and both are found in the midwestern U.S. The two species are the flat-headed peccary (Platygonus compressus) and the long-nosed peccary (Mylohyus nasutus).
Both the flat-headed peccary and the long-nosed-peccary stood about 30 inches tall at the shoulder and probably weighed around 110 pounds, much larger than this modern Chacoan peccary. Both were probably fairly omnivorous, although the long-nosed peccary utilized more browsing (trees and shrubs) than did the flat-headed peccary.
The flat-headed peccary apparently lived in herds. Sometimes these herds used caves as shelters. Large numbers of peccary bones have been found in several caves in Kentucky, Missouri, and Texas. In some cases, these finds probably represent long-term usage of a cave by herds of peccaries. Unlike the flat-headed peccary, Mylohyus was probably a solitary animal and did not frequent caves. In spite of that fact, occasionally long-nosed peccary remains are found in caves.
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