Muskrat Guard Hair
This is from the McCrone Hair Standards set, Slide #35. This is near the root of the hair. The root of the hair is on the left.
Definition/Function:
KINGDOM: Animalia PHYLUM: Chordata CLASS: Mammalia ORDER: Rodentia SUPERFAMILY: Muroidea FAMILY: Cricetidae SUBFAMILY: Arvicolinae TRIBE: Ondatrini GENUS: Ondatra SPECIES: zibethicus
Significance in the Environment:
This is a common fur used in coats, wraps, and as trim on clothing. Its presence in an indoor environment is generally indicative of clothing rather than the presence of the animal. Muskrats are also a food source in some regions of the US, Europe, and Asia.Characteristic Features:
Muskrat guard hair is around 30 to 80 micrometers wide near the root and expands or decreases to about 50 for the next half of the length. It then expands to over 100 micrometers before tapering to the tip. The medulla of the guard hair begins as a multiserial discontinuous ladder and then becomes a continuous multiserial ladderlattice until the final expansion where it becomes a cross between a latice and a multiserial ladder. Toward the tip the medulla becomes discontinuous and then disappears. The cuticle in imbricate and crenate over most of the fiber length but may begin near the root as imbricate elongate. Pigment varies from dark and heavy to light.
The fleece hair is around 10 micrometers of its entire length. The cuticle pattern is coronal simple with a count of from 7 to 12 scales per 100 micrometers. There is a concentration of pigment in the medulla in the typical rodent pattern and the medulla is uniserial ladder for most if not all of its length. The rungs may become angled. Away from the proximal end of the fiber the cuticle may become pigmented as well as the medulla.
Muskrat hair has a refractive index along its length of about 1.56 and perpendicular to its length of about 1.55. It has a birefringence of about 0.01 and a positive sign of elongation.
