What is a rat with round ears called? - briefly
Such a rodent is called a fancy rat, the domesticated variety of the brown rat (Rattus norvegicus).
What is a rat with round ears called? - in detail
The animal commonly identified by its distinctly circular ear lobes is a variety of the domesticated fancy rat. Breeders refer to this form as the “round‑ear” rat, a subset of Rattus norvegicus selected for a compact auricular shape that contrasts with the typical pointed‑ear phenotype.
Physical characteristics
- Auricles: nearly spherical, without the tapering tip seen in standard specimens.
- Fur: similar texture and coloration to other fancy rats; ear shape does not affect coat quality.
- Size: average body length 20‑25 cm, weight 300–500 g, matching the species norm.
Genetic basis
The round‑ear trait results from a recessive allele influencing cartilage development in the pinna. Homozygosity for this allele produces the rounded appearance; heterozygous carriers display intermediate ear shapes. Selective breeding maintains the allele by pairing two round‑ear individuals, ensuring a 100 % probability of offspring expressing the trait.
Breeding considerations
- Pairing two round‑ear rats eliminates the need for genetic testing of offspring.
- Maintaining genetic diversity requires occasional introduction of unrelated stock to prevent inbreeding depression.
- Litter size averages 6–12 pups; ear shape is fully expressed by three weeks of age.
Care and health
Rounded ears do not impair auditory function, but the reduced surface area may affect temperature regulation. Owners should monitor ear temperature, especially in cold environments, and keep the ear canal clean to prevent wax buildup. Standard rat husbandry applies: balanced diet, enrichment, and regular veterinary checks.
Recognition in the hobby
The round‑ear type is prized for its novelty and aesthetic appeal. Show standards often award points for ear symmetry, smooth curvature, and absence of visible cartilage folds. The phenotype distinguishes the animal in exhibitions and pet trade listings, where it is marketed as “round‑ear fancy rat” or simply “round‑ear rat.”