The Chihuahua is a passive mob in the Copious Dogs mod. It is found in the plains biome. The Chihuahua does not attack any mobs.
Taming in the Copious Dogs Mod is very similar to the way wolfs are tamed, the biggest difference is that you use a dog biscuit instead of a bone. Once the dog is tamed it will not follow you directly. You have to give it a collar, and after that, use a leash on it.
The dogs must have a distance smaller than 15 blocks between them. When the requirements are met, just feed them both a cookie and let the magic happen.
When a dog loses health, you can not feed them directly. You have to place down a dog dish and fill it. When there is enough food in a nearby dog dish, the dog will come over and start eating. The dog only eats if there are enough food in a dog dish to heal it completely.