Enamel Hypoplasia as an Indicator of Nutritional Stress in Juvenile White-Tailed Deer

Cheek teeth of 343 white-tailed deer mandibles collected from the Piedmont National Wildlife Refuge, central Georgia, were examined for the presence of enamel hypoplasia, a permanent enamel defect associated with episodes of severe physiological stress. Hypoplastic defects were observed in 27% of the individuals, with no significant difference between females (26%) and males (27%). Pit hypoplasia occurred most frequently, with most defects located on the hypoconid of the first lower molar. In white-tailed deer, the first lower molars form as fawns transition into functional ruminants and are weaned at the approximate age of 10 weeks. The presence of enamel hypoplasia at this stage in development suggests that this nutritional transition results in severe physiological stress in a large proportion of fawns each year

Sexual Dimorphism within Canine Dimensions of Didelphis virginiana

Sexual dimorphism in canine size was analyzed from a sample of the Baldwin County, Georgia population of Didelphis virginiana (Virginia opossum). Where possible 6 measurements were obtained from 59 (47 males, 12 females) individuals collected as roadkill. Although range overlap exists for all measurements, males were found to be significantly larger for upper and lower canine length, width and height. The observed sexual dimorphism agrees with previously published analyses of cranial and post-cranial sexual dimorphism in this species and is likely related to intrasexual aggression between males during mating season

Determining the Prevalence of Trypanosoma cruzi in Road-Killed Opossums (Didelphis virginiana) from Baldwin County, Georgia, Using Polymerase Chain Reaction

Twenty-nine road-killed opossums (Didelphis virginiana) collected from Baldwin County, central Georgia, were tested for the presence of Trypanosoma cruzi with polymerase chain reaction (PCR) analysis. Utilizing a cell culture containing T. cruzi epimastigotes, a positive control was established by injecting parasites into opossum heart tissue. DNA was extracted from both the control and sample heart tissues using a proteinase K protocol. PCR analysis of the isolated DNA with T. cruzi-specific primers indicated the presence of parasite DNA in at least 10.3% of the opossums in the Baldwin County sample. This study demonstrates that PCR of extracted DNA from road-killed specimens is an effective method for detecting the presence of T. cruzi in opossums

Description of a Pathologic White-Tailed Deer (Odocoileus virginianus) Mandible from Central Georgia

A pathologic mandible was observed in a male white-tailed deer (Odocoileus virginianus) harvested in central Georgia during the 2015 fall hunting season. The deer was approximately four and a half years of age and displayed no outward indication of injury or evidence of irregular tooth attrition at the time of death. Upon soft tissue removal, the mandible displayed signs of premortem trauma. The pathology was consistent with secondary bone deposition associated with bone breakage. The nature of the fracture suggests that it may have been caused by antler impact during male-to-male sparring. A physical examination of 621 white-tailed deer mandibles from the Piedmont National Wildlife Refuge in central Georgia failed to provide additional examples of similar pathology

Preliminary Analysis of the Effects of Non-target Supplemental Feeding on Camera Trap Captures of Small Mammals in Central Georgia

Supplemental bird feeding is a widespread hobby throughout western culture. Although it brings joy to many people, bird feeding has been shown to have potentially negative effects on local bird populations and small mammalian species. To study the differences in local occurrence of native small mammalian species around bird feeders and in more distant settings, six camera traps were placed in a rural residential area in Putnam County, Georgia. Three cameras were placed facing bird feeders and three placed a minimum of 60 m away from the feeders. Species presence was recorded three days a week from 12:00 am Monday to 12:00 am Thursday between 11 November 2019 and 29 January 2020. We recorded 5,073 images of mammals during the 36 days: gray squirrels (4,264), eastern chipmunks (458), raccoons (113), Virginia opossums (65), domestic cats (54), white-tailed deer (36), gray foxes (35), field mice (22), armadillos (11), eastern cottontail rabbits (11), and domestic dogs (4). Pair-wise t-tests indicate a greater frequency of image-captures of gray squirrels, chipmunks, raccoons, opossums and cats near the feeders compared to the area away from the feeders. Foxes and deer were imaged more frequently in the area away from the feeders. Not only do bird feeders contribute to a higher visitation frequency in certain species such as gray squirrels and raccoons, species known to depredate bird nests, the elevated densities of birds and mammals in the area also attract more predators such as domestic/feral cats. This study suggests that future research is needed to investigate the effects of bird feeders on the behavior of small mammals and the magnitude to which excess predation at supplemental bird feeders affects the community structure

Declining Frequency of Road-Killed Rabbits in Central Georgia

Cottontail rabbits (Sylvilagus floridanus, Sylvilagus aquaticus, Sylvilagus palustris) are a common component of the mammal fauna of the southeastern United States, yet their numbers have been in decline for at least the past 40 years. Urban sprawl, land use changes, forest maturation, and increased predation have contributed to the decline in Georgia. In the current study we explore the proposition that long-term changes in roadkill frequency track changes in wildlife populations as a whole. Using comparisons of historical data collected by Georgia Department of Natural Resources personnel and recent roadkill census data from Baldwin County, it appears that the overall decrease in the rabbit population is paralleled by a decrease in rabbit roadkill frequency in central Georgia. Using this approach, additional roadkill studies may provide reliable estimates of population trends for other commonly observed wildlife in Georgia

Eocene Terrestrial Mammals From Central Georgia

Descriptions of fossils of Eocene terrestrial mammals from the southeastern United States are rare, and particularly so in the Eocene sediments of Georgia. Here we describe a small collection of fossilized teeth and tooth fragments representing four mammalian taxa. The fossils were recovered by surface collecting overburden sediments and screen washing in situ Clinchfield Formation sediments exposed in an inactive kaolin mine, Hardie Mine, in Wilkinson County, Georgia. The Clinchfield Formation has been described as a Late Eocene coastal unit with abundant gastropods, bivalves, sharks, and rays. This is the first detailed description of terrestrial mammals from this unit. Although limited in diversity, this collection represents the most diverse Eocene-aged mammalian fauna described for the state

Identifying Roadkill Hotspots Using a Running Average

The identification of roadkill hotspots is necessary prior to the consideration of wildlife road mortality mitigation measures. In a previous study, 178 roadkill specimens were tallied via a driving survey along 21.4 km (13.3 mi) on three connected roadways in Baldwin County, Georgia. Roadkill locations were recorded to the nearest 0.16 km (0.1 mi) using the vehicle odometer. In the current study, location data were used to generate three graphical displays of roadkill distribution: 1) a linear graph of roadkills per 0.16 km (0.1 mi) bin; 2) a linear graph of roadkills per 0.8 km (0.5 mi) bin; and 3) a linear graph with a continuous running average incorporating 0.48 km (0.3 mi). The number and position of the peaks on each graph were compared in relation to roadway features that may influence animal movement and mortality such as vegetative boundaries, stream crossings, hills, and curves. The running average plot provided the best visual illustration of roadkill hotspot locations in relation to roadside features. The running average is a good technique to quickly and accurately identify hotspot locations and could help resource managers plan mitigation strategies to decrease wildlife road mortality

#35 - Enamel isotopes reveal late Pleistocene ecosystem dynamics in southeastern North America

The end of the late Pleistocene (~10,000 years ago) witnessed the extinction of over seventy percent of North America’s megafaunal genera. Although this pattern has been extensively investigated, its causal mechanisms remain elusive. Much of this difficulty is related to the spatial and temporal discontinuity of sites dating to the period leading up to the extinctions. Due to its removal from glacial conditions, southeastern North America provides a unique window into ecosystem dynamics just prior to human arrival in the region. In this study, we present new stable carbon and oxygen isotope data from Mammuthus columbiand Bison latifronsteeth collected from a well-dated Last Glacial Maximum (~20,000 rcybp) locality called Clark Quarry in coastal Georgia, USA. We compare these data to those from similarly aged (middle and late Rancholabrean) localities from Florida and demonstrate the presence of a vegetation gradient with elevated levels of C3vegetation at higher latitudes. We hypothesize that this pattern may have contributed to previously described migratory patterns of mastodon (Mammut) populations in southeastern North America. Serially-sampled δ13C and δ18O values suggest that Clark Quarry Mammuthus and Bison changed their diet seasonally with the incorporation of elevated quantities of C4vegetation during warmer periods. Our data indicate more exaggerated seasonal dietary variability in these taxa at Clark Quarry relative to those collected from the interglacial locality of Waccasassa River in Florida, providing additional evidence for the significant influence of glacial dynamics in structuring North American ecosystems

Risk of diabetes after para-aortic radiation for testicular cancer

Background: While the risk of diabetes is increased following radiation exposure to the pancreas among childhood cancer survivors, its association among testicular cancer (TC) survivors has not been investigated. Methods: Diabetes risk was studied in 2998 1-year TC survivors treated before 50 years of age with orchidectomy with/without radiotherapy between 1976 and 2007. Diabetes incidence was compared with general population rates. Treatment-specific risk of diabetes was assessed using a case–cohort design. Results: With a median follow-up of 13.4 years, 161 TC survivors were diagnosed with diabetes. Diabetes risk was not increased compared to general population rates (standardised incidence ratios (SIR): 0.9; 95% confidence interval (95% CI): 0.7–1.1). Adjusted for age, para-aortic radiotherapy was associated with a 1.66-fold (95% CI: 1.05–2.62) increased diabetes risk compared to no radiotherapy. The excess hazard increased with 0.31 with every 10 Gy increase in the prescribed radiation dose (95% CI: 0.11–0.51, P = 0.003, adjusted for age and BMI); restricted to irradiated patients the excess hazard increased with 0.33 (95% CI: −0.14 to 0.81, P = 0.169) with every 10 Gy increase in radiation dose. Conclusion: Compared to surgery only, para-aortic irradiation is associated with increased diabetes risk among TC survivors