From Sparklebox, print out animal masks to use in class, or for fun here.
From the Μαργαρίτα book series a unit on the Zoo here.
From Alphabet Soup, zoo animal coloring pages here.
From ESLjunction, animal images (can be used as flash cards, just remove english text) here
From Dover Publications, some cute zoo animals here
From Printables4Kids, print out this two copies of this zoo printable, color in the pictures and cut out. Use for a memory game.