Mary J. Wilson was born in Baltimore, Maryland in 1937. She graduated high school and realized she had a huge love of animals. She started out working at what was called The Baltimore Zoo (now the Maryland Zoo) in 1961. Before working she did not have much experience, but her hard work and enthusiasm led her to become the first Black senior zookeeper in Baltimore.
Most women at the time who were working at the zoo either worked with birds or baby animals but Wilson worked with mammals like gorillas and elephants. Sometimes she even brought work home with her – she would care for the baby animals at her home like monkeys, gorillas, and snakes. There are many stories about her even calming animals of all sizes and getting them back in their cages. She worked at the zoo for 38 years and retired in 1999.