They who?
People started keeping animals because they noticed that they can be helpful. Example: back in the day horses used to run wild( they still do, some) then the Indians started usin g them to carry foodect the ifrench saw that and noticed that horses are smart and can pull wagons and Can be ridden. I hope this answered your question, sorry if it's wrong, oh a and if your using this for a progrect for school, don't use wiki answer, some are not 100% accurate.go to your public library and read you lazy bum. If your curious, what ever.