Abstract
Transverse lines, called Harris Lines (HL), osteological markers of recovery from growth arrest episodes, are visible in radiograms of recent and Pleistocene fossil bones. Since on the one hand they mark stressful episodes in life, and on the other are mainly used to trace health fluctuations in prehistoric human communities, I used a cave bear population to check if the processes that could affect the specie’ condition were in any way reflected in the bone structure. 392 bear bones from Bear Cave in Kletno (collection: Department of Palaeozoology, University of Wrocław), dated as 32 100 ±1300 to >49 000 years BP, were radiologically examined. The bones were found in a non-anatomical position; morphological analysis indicated that they belonged to different individuals. HL shadows were observed on 9 tibiae and 3 radii: 8.8% out of the 59 tibiae and 77 radii and 3.1% of all the bones. At least 3 transverse lines were recognised in those cases; the specimens were histologically examined. The bear individuals in question experienced regular malnutrition periods during their ontogeny. Starvation resulting in growth inhibition involved young individuals, aged 1 to 4 years. Juveniles aged 6 months, i.e. before weaning, or younger, showed no signs of nutritional stress. Starvation periods associated with seasonal food deficit were not long or common and had no significant effect on the development and welfare of the species. This is the first description of the occurrence of transverse lines in the Pleistocene bear.
Highlights
Wegner [1] studied fossil human bones and observed lines of increased tissue density
The shadow of transverse lines identified as Harris lines was observed on 9 tibiae and 3 radii: 8.8% out of the 59 tibiae and 77 radii and 3.1% of all the bones
Though the studies on bone structure disturbances in the form of Harris lines are rendered difficult by an array of associations with individual morphological characters and with the environment, it is possible to assess the health condition of fossil populations based on transverse lines on the bones [31]
Summary
Wegner [1] studied fossil human bones and observed lines of increased tissue density. The interest in those lines grew with the advent of the Roentgen technique, and first attempts were made to explain such a pathological picture in human bones. It was thought to be associated with diet-induced disturbances in bone growth which led to scar formation in the spongy tissue [2]. The lines may be of different shape, thickness and course. Different definitions were proposed in the course of studies on transverse lines.
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