Micrograph of ground section, showing the basal region of the smaller exostosis (asterisk) on the left antler of the white-tailed buck (<i>Odocoileus virginianus</i>) (for location see Fig 1) and the underlying antler bone (A).

<p>Linearly polarized light plus full wave retardation plate. Note the change in collagen fiber orientation between the two portions as evidenced by the interference colors, and the continuity of the cancellous bone of the exostosis with that of the antler bone.</p

Stitched pseudo-color BSE image of the proximal portion (stalk region) of the smaller exostosis arising from the right antler of the white-tailed buck (<i>Odocoileus virginianus</i>).

<p>For location see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0173775#pone.0173775.g002" target="_blank">Fig 2A</a>. The gray levels from black (0) to peak white (255) obtained in the SEM were sequentially combined into16 bands of equal width, each represented by a different color (see inserted color bar). Higher values indicate higher degrees of mineralization. Note increasing tissue porosity and decreasing degree of mineralization of trabeculae in distal direction.</p

Images showing mineralized cartilage (asterisks) and bone (B) in the exostoses on the left zygomatic bone and right antler of the white-tailed buck (<i>Odocoileus virginianus</i>).

<p>(<b>a</b>) Micrograph of ground section, showing the central portion of the exostosis arising from the left zygomatic bone; plain transmitted light. (<b>b</b>) Pseudo-color BSE image of the tip region of the smaller exostosis arising from the right antler (depicted in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0173775#pone.0173775.g002" target="_blank">Fig 2A</a>). The gray levels from black (0) to peak white (255) obtained in the SEM were sequentially combined into16 bands of equal width, each represented by a different color (see inserted color bar). Higher values indicate higher degrees of mineralization. The mineralized cartilage shows a higher degree of mineralization than the adjacent bone. Note also the larger size, more variable shape and more irregular arrangement of the chondrocyte lacunae compared to the osteocyte lacunae. Arrows: resorption pits in mineralized cartilage.</p

Antlered cranium of the white-tailed buck (<i>Odocoileus virginianus</i>), rostro-dorsal view.

<p>The antlers exhibit several pedunculated exostoses of different size. The surface of these exostoses is rugose and characterized by crevices and some deep crater-like depressions (arrowhead). Arrow: small, sessile exostosis on the left zygomatic bone.</p

Breeding chronology and social interactions affect ungulate foraging behavior at a concentrated food resource

<div><p>Prey species must balance predator avoidance behavior with other essential activities including foraging, breeding, and social interactions. Anti-predator behaviors such as vigilance can impede resource acquisition rates by altering foraging behavior. However, in addition to predation risk, foraging behavior may also be affected by socio-sexual factors including breeding chronology and social interactions. Therefore, we investigated how time-of-day, distance-to-forest, group size, social interactions (presence of different sex-age class), and breeding chronology (pre-breeding, breeding, post-breeding seasons) affected probability of feeding (hereafter: feeding) for different sex and age-classes (mature males, immature males, adult females, and juveniles) of white-tailed deer at feed sites. We developed a set of candidate models consisting of social, habitat, reproductive, and abiotic factors and combinations of these factors. We then used generalized linear mixed models (GLMMs) to estimate the probability of feeding and used model averaging of competing models for multimodel inference. Each adult sex-age class’ feeding was influenced by breeding chronology. Juveniles were more likely to be feeding than adults in all seasons. Feeding increased with group size for all sex-age classes. The presence of a mature male negatively influenced the feeding of immature males and juveniles were more likely to be feeding when an adult female was present. Feeding decreased with increasing distance-to-forest for mature males but not for other sex-age classes. Our results indicate that each sex-age class modulates vigilance levels in response to socio-sexual factors according to the unique pressures placed upon them by their reproductive status and social rank.</p></div

Parameter estimates for generalized linear mixed model predicting the probability of feeding for immature male (≤2.5 years-old) white-tailed deer in Harris County, GA, USA, September−January, 2013−2014.

<p>Parameter estimates for generalized linear mixed model predicting the probability of feeding for immature male (≤2.5 years-old) white-tailed deer in Harris County, GA, USA, September−January, 2013−2014.</p

Influence of breeding chronology on proportion of time-spent feeding for white-tailed deer.

<p>Each sex-age class showed unique response to breeding chronology.</p

Habitat selection and diurnal refugia of gray foxes in southwestern Georgia, USA

<div><p>Understanding habitat selection of gray foxes (<i>Urocyon cinereoargenteus</i>) is essential to evaluate their potential response to changes in land use and predator communities. Few studies have evaluated temporal habitat selection or explicitly identified habitats used by gray foxes for diurnal refugia. We used GPS collars to obtain location data for 34 gray foxes (20 males and 14 females) from February 2014 to December 2015 to evaluate temporal (seasonal and diel) habitat selection and selection of diurnal refugia in southwestern Georgia, USA. We analyzed habitat selection at 2 levels, selection of a core area within the home range and selection of locations within the home range. Habitat selection was non-random (<i>P</i> < 0.001) but consistent among seasons, between day and night, and between sexes (<i>P</i> > 0.05). Hardwoods, human use (i.e., areas associated with regular human activity such as buildings, lawns, parking areas, etc.), and roads were selected (<i>P</i> < 0.05), whereas pine dominated stands were used randomly (<i>P</i> > 0.05). Selection of habitats for diurnal refugia did not vary seasonally or by sex (<i>P</i> > 0.05), with foxes selecting (<i>P</i> < 0.05) areas near hardwood forests, roads, agriculture, human use, pastures/food plots, and shrub scrub habitats. Gray foxes were observed on the ground while resting, and we found no evidence of gray foxes diurnally resting in trees. Our results suggest that on our study area, gray foxes are an edge species that prefer forests with a hardwood component in areas near human use and roads.</p></div

Candidate models used to predict the probability of feeding for mature male (≥3.5 years-old), immature male (≤2.5 years-old), adult female (≥1.5 years-old), and juvenile (<1.5 years-old) white-tailed deer at feeding sites in Harris County, GA, USA (September-January 2013 and 2014).

<p>Candidate models used to predict the probability of feeding for mature male (≥3.5 years-old), immature male (≤2.5 years-old), adult female (≥1.5 years-old), and juvenile (<1.5 years-old) white-tailed deer at feeding sites in Harris County, GA, USA (September-January 2013 and 2014).</p

Parameter estimates for generalized linear mixed model predicting the probability of feeding for juvenile (<1.5 years-old) white-tailed deer in Harris County, GA, USA, September–January, 2013–2014.

<p>Parameter estimates for generalized linear mixed model predicting the probability of feeding for juvenile (<1.5 years-old) white-tailed deer in Harris County, GA, USA, September–January, 2013–2014.</p