Do turtles get cancer?

Abstract

Turtles are renowned for their extreme longevity and tremendous range in body size. Theoretically, large, long-lived organisms should face higher cancer risks because of increased cell numbers and lifetime cellular turnover, yet cancer appears to be exceptionally rare in turtles. In the present article, we synthesize the current knowledge on cancer prevalence in turtles, drawing from zoo necropsies, pathology reports, and comparative oncology studies, and present new data spanning additional species that reinforce this pattern. Emerging molecular evidence suggests that turtles possess high resistance to oxidative stress and protein dysregulation, which may contribute to cancer resistance. Given their extreme lifespans and unique physiology, turtles represent a promising but underexplored model for studying the evolution of longevity and natural cancer suppression mechanisms.

Keywords: aging; body size; longevity; tortoises; tumor suppression.

Figure 1.

Evolutionary tree of all extant turtles based on molecular phylogenetic analyses (Thomson and Shaffer 2010). Species necropsy data included in our current study are represented by circles, with circle size proportional to the number of necropsies per species. All necropsy data shown are from the present study and are based on 290 necropsies from 64 turtle species across eight zoos in Europe, the United Kingdom, and the United States. Neoplasms (benign or malignant) detected in this study (supplemental table S1), as well as those previously reported (table 1), are marked by asterisks. The necropsy data were collected by zoo staff and retrieved from each zoo's centralized necropsy database.