How does a Dumbo rat differ from others? - briefly
Dumbo rats are distinguished by oversized, low‑set ears that give them a characteristic “elephant‑ear” appearance, and they generally exhibit a calmer, more docile temperament than typical laboratory rats. They also tend to reach a larger body size and have a slightly longer lifespan.
How does a Dumbo rat differ from others? - in detail
The Dumbo rat is a laboratory strain selected for its unusually large, low‑set ears that give the animal a distinctive silhouette. The phenotype results from a spontaneous mutation that alters cartilage development, causing the pinnae to grow outward and downward rather than upward as in standard rats.
Physically, the strain exhibits:
- Ear pinnae that may exceed 30 mm in length, positioned near the base of the skull.
- A slightly broader skull and more rounded head profile.
- Normal body mass and length compared to other outbred or inbred lines, indicating that the mutation primarily affects auricular structures.
Genetically, the trait is linked to a recessive allele on chromosome 2 that disrupts the normal signaling of fibroblast growth factor pathways during embryogenesis. Homozygous individuals display the full ear phenotype, while heterozygotes appear phenotypically normal but can transmit the allele to offspring.
Behaviorally, Dumbo rats do not differ markedly from typical strains in activity levels, learning capacity, or social interaction. However, the enlarged ears can predispose them to:
- Increased susceptibility to otitis externa due to reduced airflow.
- Higher risk of ear trauma when housed with aggressive conspecifics.
From a breeding perspective, maintaining the line requires careful pairings to avoid inadvertent introduction of other mutations. Health monitoring should include regular ear inspections and prophylactic cleaning to mitigate infection risk.
Key distinctions from other laboratory rats:
- Ear morphology: dramatically enlarged, low‑set pinnae.
- Genetic basis: specific recessive mutation affecting cartilage growth.
- Health considerations: ear‑related pathology more common.
- No significant differences in size, metabolism, or cognitive performance.