Abstract: Translocation programs for endangered mammalian carnivores face numerous challenges, including the potential for lethal interactions between releasees and resident conspecifics. Here we evaluate whether familiarizing residents with the scent of releasees might be an effective strategy for reducing aggression following Tasmanian devil (Sarcophilus harrisii) translocation. Tasmanian devils live in loose social networks in which residents have overlapping home ranges and use communal latrines. In a controlled ex situ experiment, we first found that devils readily distinguished between the feces of familiar and unfamiliar conspecifics. Next, we swapped feces between devils slated for release and wild resident devils, seeding a random half of communal latrines in the wild with the feces of releasee prior to their release, and used motion-activated video cameras to record devil visits. Wild resident devil visitation frequency and olfactory communication behaviors initially increased at experimental latrine sites where feces were deposited but not at control sites. After release, the translocated devils used both types of latrine sites and spent more time investigating experimental sites, but investigatory and scent-marking behaviors of the wild resident devils decreased, suggesting that they had become familiar with the releasees through scent. We further show that Tasmanian devil latrine sites are strongly associated with ecotones and the presence of shrubs. These findings contribute to our understanding of Tasmanian devil scent ecology and suggest that devil translocations conducted into existing populations would benefit from familiarization through latrine scent manipulation. More broadly, our results suggest an important role for scent ecology in carnivore translocation programs. Significance statement: A conservation management action that is being trialed for endangered Tasmanian devils is to breed devils in human care and reinforce dwindling small resident populations through translocation. However, with limited social interactions, unfamiliar devils may interact aggressively, increasing injury and reducing translocation success. Scent communication is nearly ubiquitous in mammals and may be a prerequisite for management of social aggression. Almost nothing is known about devil scent ecology. Our discovery that devils become familiarized with conspecifics through feces, combined with findings that wild devils that are exposed to translocated devil scent in advance of release show reduced interest in scent-seeded latrines, even after new devils are released, suggests that devils familiarized through scent in advance of relocation may exhibit reduced aggression. These results provide an avenue for improving the success of translocations for devils and other at-risk solitary mammalian carnivores.

Identifying the genetic architecture of complex phenotypes is a central goal of modern biology, particularly for disease-related traits. Genome-wide association methods are a classical approach for identifying the genomic basis of variation in disease phenotypes, but such analyses are particularly challenging in natural populations due to sample size difficulties. Extensive mark-recapture data, strong linkage disequilibrium and a lethal transmissible cancer make the Tasmanian devil (Sarcophilus harrisii) an ideal model for such an association study. We used a RAD-capture approach to genotype 624 devils at ~16,000 loci and then used association analyses to assess the heritability of three cancer-related phenotypes: infection case-control (where cases were infected devils and controls were devils that were never infected), age of first infection and survival following infection. The SNP array explained much of the phenotypic variance for female survival (>80%) and female case-control (>61%). We found that a few large-effect SNPs explained much of the variance for female survival (~5 SNPs explained >61% of the total variance), whereas more SNPs (~56) of smaller effect explained less of the variance for female case-control (~23% of the total variance). By contrast, these same SNPs did not account for a significant proportion of phenotypic variance in males, suggesting that the genetic bases of these traits and/or selection differ across sexes. Loci involved with cell adhesion and cell-cycle regulation underlay trait variation, suggesting that the devil immune system is rapidly evolving to recognize and potentially suppress cancer growth through these pathways. Overall, our study provided necessary data for genomics-based conservation and management in Tasmanian devils.