Wrinkly skin on an animal can make it seem be cute and endearing, or wise and worried--but what does it really mean? Here is a line up of some of the worlds wrinkliest breeds, how they got that way, and in some cases how this deviation for typical skin conformation affects their health and well-being.
Many breeds of dog are know for their wrinkled skin including the Basset Hound and Neapolitan Mastiff and a number of other Mastiff breeds. But perhaps most famous and most extreme in its wrinkles is the Shar Pei.
Originating as a farm dog in China, the AKC breed standard calls for loose skin and wrinkles which are most obvious in the puppy. The Shar Pei was originally a fighting dog and loose skin was thought to help the dog maneuver and strike back even when another dog had a grip on it.
In 2008 researchers from the Universitat Autònoma de Barcelona determined that these wrinkles are caused by a genetic disorder called mucinosis--where excessive production of hyaluronic acid under the skin produces loose folds and thickening of the skin. researchers think a similar gene may be responsible for an inflammatory condition (called 'periodic fever disorder') in humans.
Unfortunately shar peis now suffer from a number of congental disorders, some if which relate to the extreme wrinkling of the skin--for example they are susceptible to skin disorders such as dermatitis.Modern breeders are trying to strike a healthy balance that maintains the breed's distinctive appearance without exaggerating it to the point that it is damaging to the dog's well-being.
Pugs are also known for having wrinkles, especially on their face. When excessive these can lead to defects like impaired breathing and the development of corneal ulcers.
Meishan pigs, originating from China, are know for their wrinkled faces and long droopy ears. This breed was developed as a backyard or small farm pig. The genetic basis for the Meishan's appearance does not seem to be known and it is not a deliberately produced trait. Researchers are now investigating breeding Meishans with pigs used in large commercial farms because it has some important advantages such as becoming sexual mature and able to breed at a relatively young age and having large litters of piglets.
The Vietnamese pot-bellied pig is also know for wrinkled skin, especially on its head.
While hairless animals tend to look more wrinkled even when they are not (because the wrinkles are easier to see), some hairless lines of mice also have looser and more wrinkled skin--as do some transgenic rat lines.
The merino sheep produces a full, heavy fleece that is a valuable commodity for used in many different products. About 5% of merinos, called "A Type", carry extra wool because of extra skin that produces deep wrinkles. Wrinkles around the neck contribute to the very distinctive appearance of this breed.
Wrinkles in the rear (or "breech") of the sheep can make it susceptible to 'fly strike' when maggots live in the damp fleece and skin folds cause severe injury to the skin and pain to the animal. This issue has sometimes required a painful procedure called 'mulesing', which involves striping the skin from under the tails of lambs so it grows back smoother. This is often performed without analgesia and is a significant animal welfare concern.
While wrinkling can contribute to the appeal of a breed of domestic animal or contribute to important production traits--but when taken to the extreme it tend to lead to disease and infections risks and be detrimental to the welfare of the animal. Breeders and purchasers need to be aware that wrinkling, like any marked deviation from the healthy 'wild type', is a characteristic that should not be bred to extremes purely for novelty value or to benefit immediate profit at the expense of animal welfare.
- Asher, L., Diesel, G., Summers, J. F., McGreevy, P. D., & Collins, L. M. (2009). Inherited defects in pedigree dogs. Part 1: Disorders related to breed standards. The Veterinary Journal, 182(3), 402-411.
- BBC News - Shar-pei wrinkles explained by dog geneticists
The genetic cause of the Shar-pei dog's wrinkled skin is explained by scientists.