Animals are unpredictable creatures. With anything unpredictable (motion; changing light) you’ll want to keep timing in the front of your mind while photographing.
Animals, both willing and unwilling, have been the subject of photographs since the earliest daguerreotype in 1839. Capturing an image of an animal was a tricky business back then, when exposure times of 10 to 60 seconds were needed. These days digital cameras and smart phones make the process much easier, but getting a good photo is still tricky.
W.C. Fields famously said, “Never work with animals or children.” Photographer Elliott Erwitt, on the other hand, said, “I like working with children and animals. They are more obedient than most grownups. . . and they don’t ask for prints.” Erwitt has a unique way of getting humourous and idiosyncratic photos of dogs, yet manages to show our human connection with them. Many of his dog photos show people interacting with animals, and timing seems to be the critical component.
Photo tip: Try observing an animal for some time before taking a photo; often the interaction with people makes a great moment. Stay ready to press the button.