Bonnet Cavy Breed: History and Genetics

Bonnet Cavy Breed History and Genetics

Bonnet Breed History

The history of the Bonnet cavy began as a complete accident in the late 1990s.  The late New Zealand cavy judge and breeder, Ethel McKeown of Nemora Cavies based in Whangārei, paired two standard self-cavies together.  To her surprise, the resulting litter was born with a distinct, recurring coat anomaly.  Rather than dismissing these animals for their coats, Ethel was captivated by the unique look of this natural 'fur fault'.  Recognizing its genetic potential, she embarked on a meticulous program of selective breeding to isolate, stabilize, and intentionally develop the trait.

Ethel McKeown introduced her new creation to the New Zealand cavy fancy under the Rare Varieties exhibition section.  She officially debuted the breed at the 17th National Show in 1997, where three of her Nemora Bonnets successfully placed under the judges.  Following this breakthrough, a dedicated breed standard was drafted. Through continued stabilization of the complex modifier genetics, the Bonnet achieved formal status by the 20th National Show in 2000, where they were officially graduated out of Rare Varieties and moved into the competitive Rough-coat Group.

Despite their charismatic appearance and historic status as one of only five pedigree guinea pig breeds completely unique to New Zealand, the Bonnet faced a quiet decline.  As older fanciers retired and the number of local breeders dwindled, with no support in place when numbers become too low, the breed gradually vanished from exhibition tables.  Devastatingly, the Bonnet was officially declared extinct in 2024 by our club.  While the technical standard is permanently preserved within the New Zealand Show Standards, there are currently no known living animals or active studs remaining, cementing its status as a tragic 'lost breed'.

Bonnet Breed Genetics

  • The Dominant Gene (R): Controls the presence of rosettes in the coat (where (rr) results in a smooth coat).

  • The Modifying Genes (mm): Enhance the (R) gene effect.  Full, beautiful rosetted coats require an (RRmm) genotype.

  • The Reverse Hair Trick: When the genotype features (RrMM) or (RRMM), the cavy displays the characteristic backward-growing hair on its toes and feet, which was heavily tied to the development of the Bonnet's unique body ruffles.


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