Hair whorls in the dog (Canis familiaris). I. distribution. "Hair whorl characteristics were assessed in the domestic dog (Canis familiaris) in the regions of cephalic, cervical (dorsal, ventral, and lateral), thoracic and brachial axillary regions, the chest, shoulders, elbows, ventral abdominal region, and on the caudal thighs (ischiatic). They were classified as simple or tufted, and their position was recorded as the distance between their centers and bony landmarks within each region. The distribution of whorls was explored in a cohort of domestic dogs (N = 120) comprising a variety of breeds and cross-breeds, sourced from shelters (N = 60) and the general public (N = 60). Whorls observed in the majority of dogs in this cohort typically occurred on the chest, brachial axillary region, elbows, and ischiatic region. Atypical whorls were present in fewer than 20% of the population, and included those on the head (cephalic), cervical regions (dorsal, ventral, and lateral), shoulders, thoracic axillary region, and on the ventral abdominal region. The majority of whorls on dogs were classified as simple. In contrast, those located on the elbows and the majority of chest whorls were tufted. The presence and position of whorls were often associated with several variables including coat length and thickness, and the sex and source of the dog. The palpation and hair-cluster method of whorl assessment described in this article is best suited to dogs with short-to-medium coat lengths. The current methodology developed to assess hair whorl characteristics provides a framework for future investigations into any associations between hair whorl characteristics and other canine traits such as temperament."
Hair whorls in the dog (Canis familiaris), Part II: Asymmetries. "In horses and cattle, hair whorls have been shown to act as a structural marker of reactivity and behavioral lateralization. Few studies on canine whorls have been reported and none have assessed whorl position or direction of flow. This study describes the distribution and characteristics of whorl in each of 10 regions in which whorls are typically located in dogs. Hair whorls were assessed in dogs (n = 120) and were recorded as clockwise or counterclockwise in the cephalic, cervical (dorsal, lateral, ventral), thoracic and brachial axillary, chest, shoulders, elbows, abdominal, and ischiatic regions. Bilateral whorls, including brachial axillary, elbow, abdominal and ischiatic whorls, rotated in opposing directions, allowing the dog's overall hair coat to be symmetrical. Cephalic, brachial axillary, and ischiatic whorls were consistent in their direction; cephalic and ischiatic whorls were clockwise on the right side of the body, and counterclockwise on the left, whereas right brachial axillary whorls were counterclockwise and left were clockwise. The central chest whorl was predominantly counterclockwise (91.21%). Direction of whorls was associated with several factors, including coat length, coat thickness, sex and source of the dog."
Photo: flickr/Laertes
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