New research shows bigger animals get more cancer, defying decades-old belief

A longstanding scientific belief about a link between cancer prevalence and animal body size has tested for the first time in our new study ranging across hundreds of animal species. If larger animals have more cells, and cancer comes from cells going rogue, then the largest animals on Earth—like elephants and whales—should be riddled with tumours. Yet, for decades, there has been little evidence to support this idea. Many species seem to defy this expectation entirely. For example, budgies are notorious among pet owners for being prone to renal cancer despite weighing only 35 g. Yet cancer only accounts for around 2 percent of mortality among roe deer (up to 35 kg). Peto’s paradox is that bigger, longer-lived species should have higher cancer prevalence, yet they don’t seem to. Back in 1977, Professor Sir Richard Peto noted that, on a cell-by-cell basis, mice seem to have much higher susceptibility to cancer than humans. This has led to speculation that larger species must have evo ... Read full article.