Marey's chronophotographic gun was made in 1882, this instrument was capable of taking 12 consecutive frames a second, with all the frames recorded on the same picture. Using these pictures he studied horses, birds, dogs, sheep, donkeys, elephants, fish, microscopic creatures, molluscs, insects, reptiles, etc. Some call it Marey's "animated zoo". Marey also conducted the famous study about cats always landing on their feet. He conducted very similar studies with a chicken and a dog and found that they could do almost the same. Marey also studied human locomotion. He published another book "Le Mouvement" in 1894.