What are tailless rats called? - briefly
The condition is identified as the tailless (tl) phenotype, so affected rodents are referred to as tailless rats or tl rats. In scientific contexts they are listed as Rattus norvegicus tailless.
What are tailless rats called? - in detail
Rats that naturally lack a tail are most commonly referred to as tailless rats or rat‑tails mutants. In scientific literature the condition is described as “tailless phenotype” and the animals are designated by the strain name “tailless (tl) rat”.
The tailless phenotype appears in several laboratory strains:
- tailless (tl) rat – a spontaneous mutation first recorded in the 1930s; the mutation is autosomal recessive and results in complete absence of the vertebral column that would form the tail.
- Short‑tailed (stk) rat – a separate mutation that produces a markedly reduced tail rather than total loss; sometimes grouped with tailless varieties for comparative studies.
- Nude (nu) rat – primarily known for hairlessness, but some colonies exhibit a secondary tailless mutation when cross‑bred with tl individuals.
The genetic basis involves disruption of the Hox gene clusters that regulate axial skeleton development. The tl allele interferes with the expression of Hox10 and Hox11 paralogs, preventing formation of caudal vertebrae. Homozygous tl/tl individuals display a smooth dorsal surface where the tail would normally arise, while heterozygotes retain a normal tail.
Researchers employ tailless rats for several purposes:
- Neuroanatomical studies – the absence of a tail simplifies access to the spinal cord and facilitates implantation of recording devices.
- Developmental biology – the mutation provides a model for investigating axial patterning, vertebral segmentation, and the role of Hox genes.
- Behavioral testing – altered balance and locomotion due to the missing tail allow assessment of compensatory motor strategies.
Breeding programs maintain the tailless line by pairing homozygous carriers. Genetic screening confirms the presence of the tl allele through PCR amplification of the mutated region. Colony management includes monitoring for associated anomalies such as reduced body weight and occasional skeletal deformities in the lumbar region.
In summary, rats without a tail are identified as tailless rats, specifically the tl strain, characterized by an autosomal recessive mutation that eliminates caudal vertebrae. The phenotype serves as a valuable tool in multiple biomedical research fields.