Adopting or purchasing a puppy is a big undertaking that comes with big responsibility. New owners should research their breed of interest carefully, paying special attention to known disorders, special needs and overall breed disposition. Chihuahua babies are moderately "special needs," but what you give in extra effort is paid back a thousand fold in love and loyalty.
Chihuahuas are part of the American Kennel Club's Toy Group. The AKC specifies a maximum weight of 6 pounds for an adult show chihuahua, but non-show dogs can be as heavy as 10 pounds. There is no minimum weight standard. Baby chihuahuas are typically less than a pound at birth.
Chihuahuas are fairly hardy and susceptible to no known pathogens, but they can develop patella luxation and eye problems. Patella luxation is a popping in the knees. If it is going to appear in a particular dog, it is usually present from puppyhood. It's not painful, but the knee joints can become arthritic later in life.
Chihuahuas are high-metabolism animals that release a lot of body heat, so they get cold easily. Baby chihuahuas are especially prone to the cold, so keep plenty of soft, warm places available in the early going. Clothes are recommended for adult chihuahuas in temperatures below about 70 degrees F.
Baby chihuahuas bond quickly with their owners, and they often remain specifically loyal to one person. They can be a little skittish around new people or pets, but they are sweet once a relationship is established. Despite their small size, they actually make excellent watch dogs since they are wary of strangers, are territorial and can be a little barky.
Baby chihuahuas are born with a molera, or a soft spot on the crown of the skull. This is partially due to their size, as the incomplete skull makes it easier for the mother to birth them. The spot fills in after about six months, but in their early days, Chihuahuas should not be "wrestled" with or left in areas that could lead to a fall and potential head injury.