Wilhelm von Osten

Wilhelm von Osten, was a german amateur horse trainer,   mathematics teacher,  phrenologist, and something of a mystic. Hans was said to have been taught the horse Clever Hans to add, subtract, multiply, divide, work with fractions, tell time, keep track of the calendar, differentiate musical tones, and read, spell, and understand German. Von Osten would ask Hans, "If the eighth day of the month comes on a Tuesday, what is the date of the following Friday?” Hans would answer by tapping his hoof. Questions could be asked both orally, and in written form. Von Osten exhibited Hans throughout Germany, and never charged admission. Hans's abilities appeared on page six of The New York Times. After von Osten died in 1909, Hans was acquired by several owners. It is believed that the horse was put to use in some capacity in World War I. After 1916, there is no record of him and his fate remains unknown.

The horses abilities were scientifically investigated for details see Clever Hans.