Coat characteristics of seasonal molting mammals reveal significant seasonal variation as an adaptive strategy to cope with seasonal climate changes. However, the adaptive significance of such morphological variation has not yet been addressed. We analyzed seasonal variation of microscopic indices of hair and skin of adult Siberian weasels (Mustela sibirica manchurica Brass) from the Tonghe forest area of the Xiaoxing’anling Mountains, Heilongjiang. Skins from 8 males and 8 females were collected from summer (July to September), and an additional 8 male and 8 females skins were collected from winter (November to December )(i.e., n=32). Morphological indexes included length and width of guard hair, cuticular scale patterns of guard hair, external and cross-section form of guard hair, and medullary characteristics. We found significant differences between winter and summer coat hair density, hair length, and proportion of medulla-absent part of guard hair. We discuss the adaptive mechanism of this seasonal variation.
Down hairs were sampled from twenty two winter skins of the Tibetan antelope (Pantholops hodgsonii). For each individual,5 down hairs were collected from each sampling site including vertex,scruff,mid-back,buttock,mid-belly,tail,forelimb and hindlimb and subjected to morphological examination. Morphological indices of the hairs were measured,including hair curled length,hair uncurled length,hair diameter,scale height,scale width,longitudinal scale density,and then crimp ratio and scale aspect ratio were calculated. The results indicated that scales throughout the hair shaft were coronal type,like overlay of cups. The hair diameter in all sampling sites was between 11.69±1.25 μm and 12.41±0.79 μm. Both the curled length and uncurled length of the hairs on vertex,scruff,mid-back,buttock and midbelly were significantly longer than on tail and limbs (P<0.05). Crimp ratio varied between 11.62±2.78% and 19.79±3.22%,and crimp ratio on vertex was significantly higher than on other sites (P<0.05). Scale height varied between 20.55±4.79 μm and 25.58±5.86 μm,and scale height on limbs was significantly lower than on other sites (P<0.05); Scale widths ranged from 10.09±1.49 μm to 11.33±1.98 μm amongst all sampling sites. Scale widths on vertex and hind limb were significantly lower than on other sites (P<0.05); Scale aspect ratio varied between 2.15±0.60 and 2.56±0.81,where the ratio on mid-back were significantly higher than on other sites (P<0.05); The longitudinal scale density ranged from 38±3 scales/mm to 46±9 scales/mm,where the tail was significantly higher than other sites except hind limb (P<0.05). Morphological characteristics of down hairs of Tibetan antelope and their differentiation in different body sites are to meet the different functional requirements.
