Disease is increasingly recognized as a threat to the conservation of wildlife, and in many cases the source of disease outbreaks in wild carnivores is the domestic dog. For disease to spill over from a domestic to a wild population, three conditions must be satisfied: susceptibility of the wild species, presence of the disease agent in the domestic population, and contact between the two populations of interest. We investigated the potential for disease spillover from the domestic dog population to the wild carnivore population in the Isoso of Bolivia, an area of tropical dry forest contiguous with a national park. Using questionnaires and discussions with residents, we gathered data on the demography of dogs in the Isoso, including adult and neonatal mortality, litter size, and hunting frequency. We analyzed a large data set containing self-recorded information on hunting in various communities of the Isoso to determine the extent of dog participation in hunting and the duration of hunting trips. Finally, we took blood samples from dogs in the Isoso for a serosurvey of common canine pathogens. More than 95% of dogs had positive titers to canine distemper virus and canine parvovirus. There was also a high seroprevalence in dogs for other pathogens, a high population turnover of dogs (which may allow diseases to be maintained endemically), and frequent opportunities for contact between domestic and wild carnivores. Based on our results and the susceptibility of wild species previously reported in the literature, domestic dogs represent a disease risk for wildlife in the Bolivian Isoso.

Change in developmental timing is one source of heritable variation upon which selection can act. However, the amount of variation possible in ontogenetic trajectories is often unknown. We used three different-sized conspecific breeds of domestic rabbits to investigate the extent of variation in growth trajectories of craniofacial morphology. The growth and adult morphology of several structures (one soft tissue and 15 skeletal) were quantified and analyzed. We took two views of radiographs at close time intervals throughout ontogeny, from one week of age through adult size. Measurements from the radiographs were analyzed using a Gompertz growth model. Between-breed differences in model parameters were tested using one-way ANOVA. Few significant differences existed between the white and giant rabbits, but several differences were found between the white and dwarf breeds. Similarly, comparisons of adult morphology showed that white and giant rabbits are the same shape, while dwarf rabbits have shorter and broader snouts than white rabbits. The variation in size among breeds appeared to be due to differences in the length of time spent growing at rates near the maximum growth rate. While no one parameter of this model quantifies this pattern, differences in duration of maximum growth rate can be seen in the first derivative of the growth trajectory. Small changes in the model's parameters that measure rate and timing of growth have large morphological consequences, indicating that heterochronic changes are important sources of variation.