Crictor by Tomi Ungerer is about an old woman who is given a boa constrictor by her son. Initially shocked by the gift she does the right thing, studies up on boas and sets out to provide a good home for snake, whom she names Crictor.
There are a few oddities to the book, like the woman feeding a milk bottle to Crictor. Snakes aren't mammals and don't drink milk. But it's a minor point in an otherwise delightful book.
The illustrations are primarily done in green, white and black. The lady gets a few red highlights, like her hat. The line drawings are humorous and more comic than realistic. They remind me a bit of the style used for The Plant Sitter by Gene Zion but it's not the same author or artist.
The book was first released in 1958 and re-released as a Reading Rainbow book in 1983. It's on ALA's Notable Children's book list 1940-1959 and is on Horn Book fanfare honor list.