The Jack Chi, also called Jackahuahua or Jackhuahua, is a small mixed breed dog resulting from crossing a Jack Russell Terrier with a Chihuahua. It typically weighs between 8 to 18 pounds, stands about 12 to 15 inches tall, and has a lifespan of 10 to 18 years. This breed combines the lively, energetic temperament of the Jack Russell with the loyalty and affectionate nature of the Chihuahua, making it a playful, alert, and devoted companion.