Jack (died 1890) was a Chacma baboon who was an assistant to a disabled railway signalman, James Wide, in South Africa.

Jack was the pet and assistant of double leg amputee signalman James Wide, who worked for the Cape Town–Port Elizabeth Railway service. James “Jumper” Wide had been known for jumping between railcars until an accident where he fell and lost both of his legs below the knee.^[2] To assist in performing his duties, Wide purchased Jack in 1881, and trained him to push his wheelchair and to operate the railways signals under supervision.

An official investigation was initiated after someone reported that a baboon was observed changing railway signals at Uitenhage near Port Elizabeth.

After initial skepticism, the railway decided to officially employ Jack once his job competency was verified. He was paid twenty cents a day, and half a bottle of beer each week. It is widely reported that in his nine years of employment with the railway com