Trainers for animals often appear in the photographs Muybridge took at the Zoological Society of Philadelphia. The activities performed by Denver the mule during different photographic sessions (below, left) are incorporated into one final print (below, right).

The cyanotypes pictured below allow the viewer to see the draped figure of the model, Mr. Tadd, in both lateral and side views. Mr. Tadd was one of the drawing instructors at the University of Pennsylvania at the time Muybridge made these photographs. The university provided a number of teachers, students, and other men, women, and children to participate in this study of “the movements of everyday life.” Records show that Muybridge also photographed Mrs. Tadd and the Tadd children.