Sounds like the environment of humans is the explanation. If you were to put a whale in a human city, eating and working there, maybe the whale would have the same rate of cancerous cells
The effect isn't due to humans being an outlier, it can be seen across a range of species.
> A 2015 study, the San Diego Zoo, surveyed results from 36 different mammalian species, ranging in size from the 51-gram striped grass mouse to the 4,800-kilogram elephant, nearly 100,000 times larger. The study found no relationship between body size and cancer incidence, offering empirical support for Peto's initial observation.[8]
> A 2015 study, the San Diego Zoo, surveyed results from 36 different mammalian species, ranging in size from the 51-gram striped grass mouse to the 4,800-kilogram elephant, nearly 100,000 times larger. The study found no relationship between body size and cancer incidence, offering empirical support for Peto's initial observation.[8]