from the book, "Petrified Lightning"
Many animals are able to feel vibrations at much lower energy levels than humans can. Scientists now know that some animals can feel earthquake vibrations long before humans even become aware that the ground is shaking. This provides a method of earthquake prediction, and much research on animal reactions to seismic activity is being carried out at leading institutions of higher learning.
Animal reaction to an earthquake preceding human awareness has been known for a long time. In March 1933, a young couple driving home to their farm located just outside of Long Beach, California, were amazed to see their cows all lying flat on the ground, with heads outstretched in a wheel—like pattern. The couple stepped into the circle and tried to nudge the animals to their feet, but to no avail. The cows rigidly remained in this protective circle. A few minutes later the disastrous 1933 Long Beach earthquake struck with all its fury.
More recently, on August 6, 1979, the San Francisco peninsula was rattled by a moderate quake that added more credibility to animal prediction of earthquakes. Minutes before the quake struck, caretakers noted that zebras, ostriches, deer, and antelope, which normally intermingle in the African veld, separated themselves by species, each grouped and huddled together. It was as if the species were angry with each other. Within one half hour after the tremor, all animal behavior returned to normal as if nothing had happened.