Jack Russell Terrier puppies have many distinctive characteristics, including: Size: Jack Russell puppies are small but sturdy, with a compact, muscular body. They are usually 10–15 inches tall at the shoulder and weigh 13–17 pounds. Coat: Jack Russell puppies have a dense, coarse coat that is predominantly white with tan, brown, or black markings. Their coats can be smooth, broken, or rough, with broken coats having patches of both smooth and rough fur. Eyes: Jack Russell puppies have dark brown eyes. Ears: Jack Russell puppies have ears that fold over in a "V" shape. Tail: Jack Russell puppies have a short tail that is constantly wagging. Temperament: Jack Russell puppies are alert, happy, and fearless, but can also be a little nervous. They are also very vocal and tend to bark when they're excited. Energy level: Jack Russell puppies are high energy and need a lot of exercise and mental stimulation. Shedding: Jack Russell puppies shed moderately year-round, but they shed heavily during the spring and fall seasons. Grooming: Jack Russell puppies need to be groomed regularly to keep their coats healthy and shiny. Socialization: Jack Russell puppies should be socialized between 8–14 weeks old to help subdue their instincts.