But it is very rare, and even at best, there must be an obscure reason why they got cancer. Mamalian bodies were designed to deal with cancer on their own, provided that they have the nutrients to do so. I'm not sure you've seen the lengthy statistics of how in the US, in 1900 cancer ratio was 1:30, now it is 1:2. Obviously there is a correlation between modernization and cancer. The same can hold true for animals and has been displayed all over the world. Prime examples are aligators in florida getting cancer/ feminine characteristics/ lack of reproducing because of pollution. Also, the fish in the pacific are getting plenty of cancer due to the accumulated trash pile the size of texas. I agree with you animals can get cancer in their natural habitats away from cancer, but in my knowledge cancer in animals is very rare without human intervention.
The many sources and articles I have looked at refuting my stance say that animals do in fact get cancer in the wild, but it is largely correlated with air and water pollution. Also, much information is highly biased on this topic. There was a study I read that "proved" wild animals get cancer rates similar to humans. However, when digging up more on the study I found that the animals used in the study were animals from the zoo.
Also, many dissenters argue that tasmanian devils' cancer rates are threatening their species. However, what they dont say is that the whole thing started because humans attempted to breed groups of them to increase their population, however when in human care, tasmanian devils contracted a man made cancer causing virus. Now, after being let out in the wild tasmanian devils with the virus can cause others to contract it and get cancer as well. The information on that topic is extremely filtered because it is actually a huge problem in australia as scientists are trying to control the population of tasmanian devils from spreading the disease.
In theory, yes all animals can get cancer in the form of trophoblasts, however all wild animals have a mechanism to control that. Cancer should be looked at as a healing process gone wrong. Scientists are actually working right now to use and manipulate cancer in regenerating tissue.
I am very interested in studying the sources you looked at for this topic. This would help me in my writing of cancer. If you can't find them, its cool, but if you can, that'd be great.