It thus is important that an antelope be so marked that another antelope will recognize him at long range. Each flock of antelope watches the distant surrounding flocks, and each flock thus mutually aids the others by acting as an outlying sentinel for it. If a flock sees an object approaching that may be an enemy it strikes attitudes which proclaim alarm, and, definitely marked, their actions at once give eye messages of alarm to all flocks in view and close enough to make out what they are doing. It would thus seem that the revealing colours of the antelope have been of help in protecting--that is, perpetuating, the species. The antelope is nervous and is easily thrown into a panic. Though it is often canny and courageous, it lacks the coolness, the alertness, and the resourcefulness--that is to say, the quick wit and adaptability--of the mountain sheep. In the Yellowstone and the Wind Cave National Parks are numbers of antelope. Many of these have readjusted themselves to the friendly conditions and have lost most of their nervousness and fear of man. They have a bump of curiosity. I paused one afternoon to talk to a homesteader on the prairie. He was fencing, and presently commenced stretching a line of barbed wire. The penetrating squeaks of the wire reached the ears of several unseen antelope and appealed to their curiosity. They came close, about the distance from third to home plate. Well might they have shown concern at barbed wire! It has wrought terrific destruction to the species. A generation or so ago it appears to have been easy for the hunter by displaying a red flag or some partly concealed moving object to rouse antelope curiosity and to lure numbers. I have repeatedly seen this trick tried and a few times I have patiently endeavoured with this appeal to bring a flock within range of my double-barrelled field glass, but I didn’t succeed. They promptly went over the horizon. They are curious still, but have become wiser. I suppose it will never do to reach final conclusions concerning what an animal will do under new conditions. After a few years of intimate acquaintance with the plains antelope I visited the Yellowstone region, thinking that I was well grounded in all antelope habits. One day I came upon a flock in a deep grassy forest bay in the edge of a dense woods. Thinking to get close I walked in behind them. To my amazement they darted into the woods, dodging trees right and left like lightning, and hurdling fallen trees as readily as any deer or mountain sheep that I have seen. They well illustrated a phase of animal behaviour called ecology, or response to environment. The pronghorn or antelope is distinctly American. Fossilized antelope bones have been found in western Nebraska that are estimated to be two million years old. This antelope family is not related to the African or Asiatic antelope, nor to any American mammal species; it is alone in the world.