Goat wattles, often called tassels, are a common anatomical feature found on many domestic breeds. These small, pendulous appendages spark curiosity because they appear to serve no obvious modern purpose. Their presence is determined by genetics and evolutionary history, leading to ongoing scientific investigation into their origin. Understanding the science behind wattles requires examining their physical composition, inheritance, and the theories explaining their persistence.
What Goat Wattles Are
Wattles are small, paired appendages typically hanging from the throat area near the jawline or neck of a goat. They are flexible, hair-covered growths of skin and connective tissue present from birth. Anatomically, these structures are distinctive because they contain a core of ectopic cartilage tissue.
This underlying cartilaginous structure differentiates them from simple skin tags. They are considered benign growths that do not interfere with the goat’s health or daily functions. They are usually bilateral, appearing in a symmetrical pair, though occasionally a goat may have only one or none.
The Genetics of Wattle Presence
The presence of wattles is not universal across all goats; it is a heritable trait determined by specific genetics. Scientific studies confirm that the wattle phenotype is controlled by a dominant gene, often designated as the W allele. This dominant inheritance means a kid is likely to be born with wattles if at least one parent possesses the trait.
Genetic mapping has localized the wattle trait to a specific region on goat chromosome 10. This area contains genes, such as FMN1 and GREM1, which regulate limb development and outgrowth. While wattles are frequently observed in many dairy and pygmy breeds, the trait is not exclusive to any single breed.
Why Wattles Persist: Current Hypotheses
The primary scientific explanation for why goats possess wattles is that they are a vestigial trait. This concept suggests the structure is a non-functional remnant of a feature that was functional in a distant evolutionary ancestor. The complex anatomical composition, particularly the presence of cartilage, supports the hypothesis that wattles may be rudimentary developed extremities or regressed limbs.
The association of wattle-determining genes with limb formation pathways strengthens the theory that these neck appendages are an evolutionary leftover. Since the trait does not cause harm to the animal, there has been no selective pressure to eliminate it from the gene pool. It is considered genetically neutral, allowing the dominant allele to persist through generations.
While the vestigial theory is the most accepted, minor historical hypotheses have suggested roles in thermoregulation, scent dispersal, or sexual display. These ideas lack substantial supporting evidence. The consensus remains that goat wattles are a harmless, genetically determined curiosity, echoing a structure significant in the evolutionary past.