Sexual dimorphism is documented in 35 articulated adult skeletons, 24 females, and 11 males, of the Miocene rhinoceros Teleoceras major from Ashfall Fossil Beds, Nebraska. Morphometric analysis of 51 cranial, mandibular, forelimb, and hindlimb characters reveals larger male mean values in 50 of the 51 measurements, of which 23 are significantly different (p ≤ 0.01). The most clearly dimorphic feature is the i2 diameter. The dimorphism evident in additional mandibular and cranial characters is conservative when compared with the dimorphism present in the fore- and hindlimbs. Non-overlapping male and female ranges are recorded for humerus length, radius length, radius proximal width, and femur length, with corresponding dimorphism ratios (DR = male ÷ female) of 1.11, 1.12, 1.11, and 1.10. Maximum male longbone lengths exceed minimum female lengths by an average of 24% (20–29%). Developmental maturity is apparently asynchronous in T. major, with fusion of longbone epiphyses delayed a minimum of two relative adult age classes in males. Significant sexual dimorphism is evident in the radius (DR = 1.34) and femur (DR = 1.19) cross-sectional areas. Estimates of body mass suggest a DR value between 1.13 and 1.23. The cranial, mandibular, and body-size dimorphism in T. major approaches that seen in the extant rhinoceroses Ceratotherium simum and Rhinoceros unicornis. However, the apparent herd structure and breeding-age sex ratio for the Ashfall herd suggests a behavioral ecology for T. major different from that of extant rhinoceroses. Teleoceras was likely a herding polygynous species ecologically more similar to extant Hippopotamus amphibius of Africa.

Quarry samples of lower cheek teeth of the Miocene rhinoceros Teleocera s are analyzed for the presence of enamel hypoplasia using macroscopic, thin-section, and scanning electron microscopic techniques. The presence of enamel pits, furrows, and groove s is noted predominantly on, but not limited to, the buccal side of dp4s. The enamel defect is not as common on permanent teeth, but does occur with decreasing frequency on p4s, mIs, m2s, and m3s.Analysis of the formative sequence of deciduous cheek teeth in Teleoc eras and the extant rhinoceros Diceros bicornis suggests that the Teleoceras dp4 was developing in the alveolu s at the time of birth . Varying degrees of wear on the dp4s exhibiting enamel hypoplasia imply that the defect-producing stress did not result in immediate death . Isolation of the enamel hypoplasia to distinct bands on the Teleoceras dp4s suggests causes linked to non-lethal severe physiological stress due to metabolic disruption or nutritional deficiency occurring at or very near birth. The Teleocera s p4 was probably developing in the alveolus between three and five years of age. The observed p4-hypoplasias appear to reflect physiological stresses not related to weaning, but to some other stressful period such as cow-calf separat ion prior to the birth of the next offspring.

Skeletal injuries, especially broken bones, diminish physical mobility of animals, and they may affect an individual’s ability to obtain food and to evade predators. We quantified and compared healed fractures in two sympatric species of tree squirrels (Sciurus niger Linnaeus, 1758 and S. carolinensis Gmelin, 1788) that differ in body size (mass) and locomotor mode. We assessed the number and location of healed fractures in two urban populations of S. carolinensis and in individuals of both species from one rural location. We found a higher-than-expected proportion of healed fractures in older animals of both species. However, we detected no deviations from expected in the number of healed fractures between the two species or between sexes within a species. Urban populations of S. carolinensis exhibited significantly higher-than-expected proportions of healed fractures, and they were approximately 4.5 times more likely to have a healed injury as compared to rural S. carolinensis. Our findings suggest that S. carolinensis in urban populations experience a higher rate of injury and/or a higher rate of survival after injury than those in rural populations.

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