Of Elephants and Other Mammals: A Comparative Review of Reproductive Tumors and Potential Impact on Conservation

Simple Summary Both Asian and African elephants are endangered, and conservation efforts aim to minimize negative impacts to each species, while increasing their population sizes. Understanding factors that impact reproduction are important for conservation. Tumors can negatively impact reproductive success, particularly when they are located in the reproductive system. This article reviews the prevalence of reproductive tumors in elephants and other mammals. The impact of human tumors and treatment options are also reviewed as a comparative approach to consider potential treatment approaches for elephants diagnosed with reproductive tumors. Future studies are needed to understand the impact of these tumors on elephant conservation and to establish fertility preserving treatments. Reproductive tumors can impact conception, pregnancy, and birth in mammals. These impacts are well documented in humans, while data in other mammals are limited. An urgent need exists to understand the reproductive impact of these lesions in endangered species, because some endangered species have a documented high prevalence of reproductive tumors. This article documents that the prevalence of both benign and malignant neoplasia differs between African and Asian elephants, with Asian elephants more frequently diagnosed and negatively affected by both. The prevalence of these tumors across mammalian species is compared, and impact plus treatment options in human medicine are reviewed to inform decision making in elephants. Evidence suggests that reproductive tumors can negatively impact elephant conservation. Future studies that document reproductive outcomes, including the success of various treatment approaches in elephants with tumors will benefit conservation efforts.