In a previous post, I stated that the Mexican Hairless breed of dog (the Xoloitzcuintli) was the only dog that could sweat through its skin. An alert reader, Dr. Daven Presgraves of The University of Rochester, has written me to say that this is an error. He cites two references, one a scientific paper and the other Wikipedia (see below). Indeed, if you think about it, skin sweating as a unique feature of the breed seems unlikely. The feature is very unlikely to be a simple byproduct of the mutation that causes hairlessness itself, and it also seems unlikely (though not impossible) that natural selection on the hairless dogs after domestication would create a system of skin-sweating. Thanks to Daven!
(1) Spontaneous comedones on the skin of hairless descendants of Mexican hairless dogs.
Kimura T, Doi K.
Exp Anim. 1996 Oct;45(4):377-84.
In the first experiment, the skin sebum and humidity, perspiration ability of sweat glands, and histology of spontaneous comedones were examined in hairless descendants of Mexican hairless dogs. The skin of females showed lower humidity than that of males. Some animals with a large number of comedones exhibited remarkably high skin sebum scores. The comedones were distributed throughout the dorsal skin, and a cluster of lesions was found mainly in the limbs and prepuces. The sweat glands showed no perspiration in the sudorific test. Histologically, both infant and adult animals had lesions of micro- and/or “blackhead” comedones. Plugged follicles containing abundant keratic substances associated well-developed sebaceous glands. Spontaneous comedones in the skin of hairless dogs were grossly and histologically similar to the acne vulgaris observed in human beings. The skin of some adult animals showed a large number of protrusive comedones which were solid cystic structures containing organized substances. In the second experiment, three kinds of antiacne agents (sulfur and camphor, sulfur and resorcinol, and ibuprofen piconol) were applied daily to the test sites for one month. These antiacne agents caused prominent extrusion of keratin plugs from follicular sites. The results suggest that the hairless dogs are a predictive model for evaluating the efficacy of antiacne agents proposed for acne treatment.
“The breed ranges in size from about 10 pounds/4 kg to 50 pounds/20 kg. Contrary to popular myth, the breed does not have a higher than normal body temperature, does not sweat through its skin and contact with a Xolo cannot heal injuries or illness. These myths are based in the breed’s traditional ceremonial use.”