Monkey jockeys race greyhounds

In the early 1930s, a new feature was introduced at some greyhound races: monkey jockeys. Apparently the crowds loved the idea. The problem was, the monkeys had trouble staying on the backs of the greyhounds. Animal trainer Rennie Renfro came up with a solution — a special harness that would tie the monkey onto the back of the dog. Renfro patented his invention in 1933.

It probably made him some money, because I can find descriptions of races with monkey jockeys for decades afterwards.

Rennie Renfro (left) and his wife
St. Louis Post Dispatch - July 2, 1933

image source: Greyhound Articles Online