First and foremost, you must choose a Chihuahua breed breeder that will provide health spaces for kneecaps and heart conditions. The Chihuahua is a long-lived breed, with an estimated lifespan of 18 years. Chihuahuas are prone to shivering when they are cold, excited or frightened. Give your Chihuahua a jumper or coat when going outside in cold or wet weather. Chihuahuas can be hostile towards other dogs if they are not socialised when they are young. Chihuahuas do not shy away from other dogs and this can cause a problem if they encounter a large, aggressive dog. Do not leave your Chihuahua unattended in the yard, it could be attacked by a hawk, other birds of prey, larger dogs or coyotes. Chihuahuas can be reserved with those they do not know, so it is recommended that you choose a puppy that has been raised in a home with a lot of human interaction.