<P> Chihuahuas may tremble or shiver when stressed, excited or cold . Chihuahuas, especially the short coat variety, are less tolerant of cold than larger breeds, and require a sweater and / or boots in cold weather . They will seek warmth in sunshine, under blankets, or on furniture, or human laps . </P> <P> Some Chihuahuas may present separation anxiety as a result of being so close and loyal to their owner . This is a fairly common cause behind any pacing, excessive salivating, destructive chewing, or barking, howling or whining in dogs . There are many treatments and tips to help prevent separation anxiety in dogs . </P> <P> The average lifespan for a Chihuahua is between 12 and 20 years . </P> <P> Chihuahuas are also known for luxating patella, a genetic condition that can occur in all dogs . In some dogs, the ridges forming the patellar groove are not shaped correctly and a shallow groove is created, causing the patella to luxate or slip out of place, sideways . The knee cap sliding across the bony ridges of the femur can cause some pain . The affected chihuahua will hold its leg flexed, and foot off the ground until the quadriceps muscle relaxes and lengthens, after which the animal feels no discomfort and continues with activity . </P>

What's the average life of a chihuahua