An animal painter, “animalier” is an artist who specializes in or is known for their skill in the portrayal of animals, essentially up to about 1900. During the last century “wildlife artist” became the preferred term for contemporary animal painters.
Especially in the 17th century, animal painters would often collaborate with other artists, who would either paint the main subject in a historical or mythological piece, or the landscape background in a decorative one. Frans Snyders, a founder of the Baroque animal painting tradition, often provided the animals, and also still life’s of food, for Peter Paul Rubens; a different landscape specialist might provide the background.
Painting animals is done already for centuries. Some of my students prefer to paint animals. I think it’s the best to paint what you love or are interested in. It makes you work more personal.