evolutionary biology

Peto´s paradox is the lack of observed relationship between the size of an animal and the prevalence of cancer, despite the fact that the greater number of cells and divisions as they get larger should increase the likelihood of cancer. A new study disproves this paradox by finding that, at least in terrestrial vertebrates, larger species do develop more cases of cancer. In quite a few of them, however, the increase is less than would be expected, suggesting that they have evolved anticancer mechanisms that remain worth studying. The results are published in the journal PNAS.  

Some animal species, such as parrots or dolphins, appear to address each other by imitating sounds from the receiver. However, animals addressing each other by individual names has only been observed in humans. Now, an international team of researchers says that African elephants can communicate through name-like calls and do not appear to rely on imitation to do so. According to the authors, who publish their results in the journal Nature Ecology & Evolution, the finding would imply that they have some degree of symbolic thinking. 

Chimpanzees can learn a new skill by observing each other — a phenomenon known as social learning — according to a study published in Nature Human Behaviour. The findings suggest that chimpanzees may have the capacity for cumulative cultural evolution, which was previously considered to be an exclusively human trait.