Your patronus form is highly personal. I've offered a general overview of animal types, and you are free to use it as a guide to picking your own patronus. As a reference for this list I've used samples from the HP canon, cultural views of animals, and my own interpretations. Have fun!

• Canine | Wolf, Fox, Dog, etc
  • When you use your patronus, you are usually trying to protect the ones you love. When you get into trouble you can rely on the friends around you to help you, just like they can rely on you. Your patronus reflects this sense of loyalty and community.
• Feline | Tiger, House Cat, Cheetah, etc
  • You are usually on a solo adventure when it's time for you to call on your patronus. You rely on your own cleverness and strength to get out of trouble. Like your patronus, you find power in independence.
• Bird | Owl, Hawk, Sparrow, etc
  • It is a rare occassion that you need to use a patronus. Usually you are outside of the line of fire, keeping yourself out of trouble. When you are in trouble, though, you are a quick thinker and you move fast, a quality you share with your patronus form.
• Deer | Elk, Red Deer, Caribou, etc
  • You often find yourself in the middle of some sort of drama, usually on accident. Like your patronus, you are quick on your feet and dangerous when cornered.
• Lesser Weasel | Ferret, Fisher, Marmot, etc
  • When you're in trouble, it's because you stuck your nose into somebody else's business. You and your patronus are curious, and you and your patronus are clever. You have confidence in your abilities, and can wiggle your way out of any situation.
• Greater Weasel | Badger, Otter, Wolverine, etc
  • Like the Lesser Weasel, you are very clever and usually find trouble through your own curiosity. However, you and your patronus are able to handle any threats through force. Physical and willful, you find it very easy to defend yourself when your back is to the wall.
• Lesser Rodent | Rat, Mouse, Squirrel etc
  • You adapt easily and roll with the punches. You're as good at getting out of trouble as you are at getting into it, and like your patronus you know when to stand your ground and when to run for cover.
• Greater Rodent | Porcupine, Capybara, Beaver, etc
  • You don't go looking for trouble -- trouble comes looking for you. You and your patronus are normally quite gentle and reserved, but when threatened you are a dangerous person. You are happy with who you are and are unbothered by threats or criticism.
• Reptile | Alligator, Snake, Turtle, etc
  • You don't mind a little trouble, and have plenty of experience with making trouble sorry it ever found you. Like your patronus, you may sometimes be misunderstood or have your motives questioned, but you don't let that sort of thing bother you.
• Amphibian | Frog, Toad, Salamander, etc
  • You rarely find yourself in serious trouble because you adapt so quickly to new situations. You enjoy learning new things and having new experiences. You and your patronus may not look like much, but you never go down without a fight.
• Genus Equus | Horse, Donkey, Zebra, etc
  • When in trouble, you draw strength from the people around you. You are social and can be stubborn, and you learn quickly from your mistakes.