There's a surprising number of vegan options for pet food and pet treats. While most pet food stores don't carry them, you can always request them (especially at locally owned stores) or you can just buy them online. The links below will take you to the related category at the Vegan Products Guide website:

• Cat Food
  
• Cat Vitamins
  
• Cat Treats
  
• Dog Food
  
• Dog Vitamins
  
• Dog Treats
  
• Ferret Food