Common Rat Breeding: Complete Guide for Responsible Breeders

Breed Overview: The Intelligent Common Rat

Common Rats (Rattus rattus), also known as Black Rats or Roof Rats, are highly intelligent, social rodents that have been domesticated as pets for over 100 years. These remarkable animals are known for their problem-solving abilities, trainability, and affectionate nature. Their intelligence rivals that of dogs, making them exceptional companion animals.

Essential Breed Characteristics

Size and Weight

Males (Bucks): 0.5-1.2 pounds, 9-11 inches body length

Females (Does): 0.4-0.8 pounds, 8-10 inches body length

Life Expectancy

2-3 years with proper care and nutrition

Temperament Profile

Intelligent, social, trainable, affectionate, curious

Coat Varieties

Standard, Rex (curly), Dumbo (large ears), Hairless, Satin

Health Considerations for Breeding

Respiratory Infections (Mycoplasmosis)

Most rats carry Mycoplasma pulmonis, which can cause respiratory infections when stressed. Breeding stress can trigger infections. Maintain excellent ventilation, minimize stress, and avoid dusty bedding. Early treatment essential.

Mammary Tumors

Common in female rats, especially unbred does. Can be benign or malignant. Early spaying reduces risk significantly. Check breeding does regularly for lumps. Genetic component means affected animals should not be bred.

Pituitary Tumors

More common in older rats. Causes neurological symptoms. Hereditary component exists. Select breeding stock from lines with longevity and no tumor history.

Parasites (Mites and Lice)

External parasites common in rats. Can cause severe itching, hair loss, and stress. Regular health checks essential. Treat before breeding to prevent transmission to pups.

Megacolon

Genetic condition associated with certain color patterns. Fatal if untreated. Avoid breeding high-white blazed rats together. Screen breeding lines carefully.

Breeding Guidelines and Best Practices

Optimal Breeding Age

Bucks: 10-12 weeks to 18 months. Full sexual maturity at 10 weeks. Fertility declines after 18 months.

Does: 12-16 weeks to 12 months. First litter should be before 8 months for safety. Peak fertility 4-8 months.

Heat Cycle and Mating

Does cycle every 4-5 days. Estrus lasts 12-20 hours, typically evening/night. Post-partum estrus occurs within 24 hours after birth - separate buck immediately. Successful mating confirmed by vaginal plug.

Gestation and Birth

Gestation: 21-23 days (average 22 days). Shortest gestation among common rodent pets. Pups born altricial - hairless, eyes closed, helpless. Birth usually occurs at night. Labor typically 1-2 hours total.

Breeding Frequency

Does: Maximum 3-4 litters per year. Allow 6-8 weeks recovery between litters. Career total 4-5 litters maximum. Bucks: Can mate year-round but limit to maintain quality.

Temperament and Behavioral Considerations

Common Rats are highly social animals requiring companionship. Breeding pairs should be compatible and calm. Bucks may become territorial during breeding. Does often more accepting of breeding when housed with other females. Intelligence allows for training and handling ease.

Whelping and Pup Care

• Gestation: 21-23 days average
• Litter size: 6-12 pups typical, range 2-20
• Birth weight: 5-7 grams
• Birth type: Altricial - helpless, hairless
• Eyes open: 14-17 days
• Ears open: 2-4 days
• Weaning age: 4-5 weeks
• Sexual maturity: 5-6 weeks (separate by sex)

Market Demand and Pup Placement

Rat pups command $20-$60 pet quality, $60-$150 show quality. Rare varieties (Dumbo, Rex, Hairless) command premium prices. Demand strongest for friendly, well-socialized pups. Pet stores often seek regular suppliers. Screening essential for proper homes understanding social needs.