Rat Terrier Chihuahua Mix
Rat Terrier + Chihuahua cross. Also called: Rat-Cha.
The Rat Terrier Chihuahua Mix typically weighs 5-15 lbs, needs 150-400 calories per day, and lives 13-18 yrs. Size, appearance, and temperament can vary widely depending on which parent's genes are more dominant.
Size and nutrition
The Rat Terrier Chihuahua Mix can weigh anywhere from 5-15 lbs (2.3-6.8 kg), a wide range that reflects the size difference between the Rat Terrier and Chihuahua. Because mixes are unpredictable, watch your dog's actual body condition rather than targeting a specific number on the scale.
Daily calorie needs for a Rat-Cha range from 150-400 kcal depending on their adult size, activity level, and whether they are spayed/neutered. Use our calorie calculator with your dog's actual weight for a personalized estimate.
Get your Rat-Cha's exact calorie needs.
CalculateHealth risks from both parent breeds
Mixed breed dogs can inherit health conditions from either parent breed. The Rat Terrier Chihuahua Mix may be susceptible to conditions common in both Rat Terriers and Chihuahuas. Mixed breeds often benefit from hybrid vigor, but this is not guaranteed, and responsible health screening of parent dogs remains important.
Look up the health profiles for both parent breeds for a complete picture of potential health concerns:
Exercise and activity
Rat-Chas are energetic little dogs that need more activity than their size suggests. The Rat Terrier's working heritage creates a high-drive dog in a compact package. Plan for 30-40 minutes of daily activity: walks, fetch, and training games. They excel at informal agility and earthdog-style activities.
Care and grooming
Short, smooth coat that needs minimal grooming; weekly brushing is sufficient. They are hardy, sturdy small dogs with fewer fragility concerns than some toy breeds. Dental care is important; brush teeth regularly. Their prey drive may make them incompatible with small pocket pets.
What to expect from a Rat-Cha
Alert, intelligent, and loyal. Rat-Chas combine the Rat Terrier's problem-solving ability with the Chihuahua's devotion to their person. They are confident dogs that may be territorial without proper socialization. They make excellent watchdogs with alert, persistent barking.
Frequently asked questions
Adult Rat-Chas typically weigh 5-15 lbs (2.3-6.8 kg). The wide range reflects the size difference between Rat Terriers and Chihuahuas. First-generation crosses (F1) are the most unpredictable for size. Looking at the parents' sizes gives the best estimate. Puppies that are larger at 8 weeks tend to be larger adults, but this is not guaranteed.
Daily calorie needs range from 150-400 kcal depending on your dog's actual adult size and activity level. Since mixes vary so much in size, use our calorie calculator with your dog's current weight rather than relying on breed averages. Weigh your dog monthly and adjust portions to maintain healthy body condition.
Mixed breeds often benefit from hybrid vigor, meaning their broader gene pool reduces the risk of conditions that concentrate in purebred lines. However, a Rat Terrier Chihuahua Mix can still inherit health issues common to either the Rat Terrier or the Chihuahua. Research both parent breeds' health profiles and ask the breeder about health testing of the parents. Regular veterinary checkups catch any inherited conditions early.
Tools for Rat-Cha owners
Disclaimer: Mixed breed characteristics vary significantly. The weight, calorie, and health information here represents the combined range of both parent breeds. Individual dogs may fall outside these ranges. Calorie estimates use the RER/MER formula (NRC 2006). Consult your veterinarian for advice specific to your dog. See our sources.
Last reviewed: April 1, 2026