Fighting for survival: context and extent of intraspecific killing among endangered Florida panthers

Context: Competition for resources (e.g. food, habitat, mate) are wide-ranging ecological circumstances that motivate life-threatening conflicts amongst wildlife, including intraspecific killing. Florida panthers are geographically isolated, endangered, and intraspecific killing risk is ubiquitous throughout a lifespan. However, little is known about the inherent range of intraspecific killing among the individuals themselves. Understanding the drivers and magnitude of intraspecific killing is necessary for resolving questions about the species’ survival in relation with the life history, population dynamics, and resiliency to environmental change. Aims: Here, I examine the cause-specific mortality and survival among independent subadults and adults to evaluate the individual-specific context and population-level extent of intraspecific killing. Methods: Using long-term cause-specific mortality data sourced from radio-collared individuals and multi-model inference, I ascertained the perpetrators, victims, motives, and evaluated the effects of intrinsic and extrinsic predictor variables on intraspecific killing risk. Key results: Irrespective of sex, intraspecific killing was the predominant fate perpetrated by both immigrating subadult and resident adult males. The intraspecific killing risk was greater for males than females and affected by life stage and reproductive status. Subadult males, females with dependent offspring, and the oldest adults were most at-risk. Conclusions: Intraspecific killing was primarily motivated by intrasexual competition to reproduce, secondly for obtaining food, and inadvertently protecting offspring from infanticide. Male victims were mainly rivals fighting to acquire or defend a territory with resident females and monopolize grouped resources. Most female victims were mothers fighting infanticidal males evidently seeking to increase breeding opportunities. The oldest victims indicate weakening in fighting ability. Implications: My results highlight a pervasive predisposition to intraspecific killing which limits the spatiotemporal coexistence and vital rates of at-risk conspecifics. Recognising intraspecific killing enhance our knowledge for evolutionary theory, conservation planning, and population management.