New research from the University of Southern Denmark shows that carnivores are less likely to get cancer than herbivores. The research was published in Nature Journal.
However, it is not known how many animals are exposed to cancers or how often their health is affected by this disease. This is not surprising as any serious illness in wild animals can lead to untraceable deaths due to starvation and predation. Cancer is an age-related disease. Older people are more likely to get the disease. It is therefore difficult to estimate the risk of developing cancer in wild animals as it is not easy to determine their age. This research was done to determine how often animals are exposed to cancer in wild animals.
This research analyzed data from 191 species and 110.148 individual mammals to show that cancer is a common disease in mammals. It can also emerge anywhere along the mammalian tree. Research also showed that cancer risk is not evenly distributed across the mammalian phylogeny. Carnivores are especially susceptible to being affected by cancer (e.g. Carnivores are particularly susceptible to cancer (e.g., over 25% of Clouded leopards and Bat-eared Foxes die from the disease), while ungulates have shown a consistent resistance to the disease.
The research also explored whether diet differences could explain the observed phylogenetic pattern of cancer risk. The results showed that eating animals, particularly mammalian prey, increases cancer risk in all mammals. The high cancer risk among carnivorous mammals could be due to their low microbiome diversity and limited physical exercise under human care. The study also addressed a fascinating evolutionary issue. Tumors are a form of disease of mutational origin. Mutations often arise during cell division. The risk of developing cancer is higher in animals with longer lifespans and larger bodies.
Multiple studies have supported this theory in humans. For example, a higher body size (or height) is associated with a higher chance of developing cancer. These correlations do not hold across species. For example, an elephant and mouse have the same likelihood of developing breast cancer, despite having different lives expectancies and body sizes. Peto’s paradox is the name for the discrepancy between the effects of body size and life expectancy upon cancer risk. This research provided clear evidence of Peto’s paradox’s validity. It proved that cancer risk was largely independent from body mass and the life expectancy of all mammals. This result supports the idea that evolution has created more effective tumour suppressor mechanisms, along with longer life expectancies and larger bodies.
Fernando Colchero, University of Southern Denmark, co-author, said, “Overall, our work highlights the fact that cancer might pose a serious, significant threat to animal welfare. That needs considerable scientific attention, particularly in the context of recent environmental modifications caused by humans.” A better understanding of the risk and resistance of different animal species to cancer can make it possible to make major advances in the search for natural anticancer defenses. This could also revolutionize cancer medicine. For example, research on species that are highly resistant can help to develop bio-mimetic natural treatment options for cancer. These treatments are not toxic to the host, contrary to many other cancer treatments. (ANI)