The Scottish Fold is a breed of domestic cat with a natural dominant gene mutation that affects cartilage throughout the body, causing the ears to "fold", bending forward and down towards the front of the head, which gives the cat what is often described as an "owl-like" appearance.
Originally called lop-eared or lops after the lop-eared rabbit, Scottish Fold became the breed's name in 1966. Depending on registries, longhaired Scottish Folds are varyingly known as Highland Fold, Scottish Fold Longhair, Longhair Fold and Coupari.
All Fold cats are affected by osteochondrodysplasia (OCD) a developmental abnormality that affects cartilage and bone development throughout the body. This condition causes the ear fold in the breed and studies point to all Fold cats being affected by it. Fold cats therefore have malformed bone structures and can develop severe painful degenerative joint diseases at an early age. Due to these health conditions, breeding Fold cats is prohibited in several countries and some major cat registries do not recognise the cat breed.
The original Scottish Fold was a white barn cat named Susie, who was found at a farm near Coupar Angus in Perthshire, Scotland, in 1961. Susie's ears had an unusual fold in their middle, making her resemble an owl. When Susie had kittens, two of them were born with folded ears, and one was acquired by William Ross, a neighbouring farmer and cat-fancier. Ross registered the breed with the Governing Council of the Cat Fancy (GCCF) in the United Kingdom in 1966 and started to breed Scottish Fold kittens with the help of geneticist Pat Turner. The breeding programme produced 76 kittens in the first three years – 42 with folded ears and 34 with straight ears. The conclusion from this was that the ear mutation is due to a simple dominant gene.
Susie's only reproducing offspring was a female Fold named Snooks who was also white; a second kitten was neutered shortly after birth. Three months after Snooks' birth, Susie was killed by a car. All Scottish Fold cats share a common ancestry to Susie.