They come in a variety of colors - black, gray, cinnamon, white and a various mixes. There are long and short-haired breeds as well as some with rosettes. They are all fast and agile runners. They have a keen sense of sight with a well developed sense of peripheral vision.
Guinea pigs can recognize all the colors of the spectrum.
The guinea pig's hearing is very keen. It can detect high frequencies that life far beyond the range of the human ear. Their sense of smell is also highly developed. It is not as keen as a dog's, but it is still far superior to ours. In the wild, Guinea pigs stay close together in groups of as few as four or as many as twenty.