PhD student Silvana Tridico from Murdoch University has worked with international colleagues and A/Prof. Paul Rigby in the AMMRF (now Microscopy Australia) at the University of Western Australia to investigate the structure of woolly mammoth hair to understand how its structure could relate to its function in the living animal. The underhairs are very springy and coiled but smooth, which would have encouraged loose intertwining to give a puffy arrangement but prevented matting. This smoothness extended to the overlying hairs, also keeping them separate. Microscopy revealed that the hairs were unusual in having multiple cores, called medullae. This is thought to contribute to the stiffness of the hairs.
Multiphoton microscopy was particularly useful in analysing the multiple medullae as it makes it possible to look deep inside the hair without having to destroy it, keeping the sample intact for further analysis. It showed that structures previously seen in cross section are continuous in the longitudinal direction. The below video shows a 3D reconstruction of the multiphoton images of autofluorescent linear structures within a mammoth hair.
Ms Tridico also studied the preservation and colouration of the hairs. There was some insect and fungal damage but she could clearly see a variety of colouration patterns. These were compared to modern animal hairs, which suggested that mammoths probably appeared mottled or speckled rather than the rusty orange colour of common illustrations. This orange colour is probably due to breakdown products of the hair itself.
Light micrograph of a woolly mammoth hair showing the long central medulla and some fungal damage showing up as projections out from the central medulla.
Silvana Tridico et al. Quaternary Science Reviews, 83, 68-75, 2014 DOI: 10.1016/j.quascirev.2013.10.032
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October 23, 2015
