Life expectancy varies considerably among members of the animal kingdom; in general, large animals live longer than small ones. Not all animal species obey this rule, however. The naked mole rat is one of them: it can live up to thirty years, which is much older than its size would seem to dictate.
Relatively small bats, as well, live much longer than would be expected for their size. A group of researchers from Trinity College Dublin studied 1300 birds and mammals, relating the animals’ life expectancy to their size. Lifestyle turned out to be an important factor: animals living in trees or nests, or able to fly, were noted to live much longer than expected on the basis of size. These species reduce the risk of death by external factors such as drought or predation: they can escape! This research provides an explanation for the unusually long lifespan of many birds or bats. A good example is the oldest wild bird, Wisdom, an albatross 63 years old. Compared to other flying animals, most bats are actually not extremely long-lived.
The results of this research can help to identify extremely long-lived species more accurately.