Large Body Size Lowers Extinction Risk, Study Reports

Scientists at the Santa Fe Institute have discovered that increased body size may help certain species avoid extinction, according to a new study published in the journal Nature Communications.

Almost all current extinction models are simple in that they only compare reproductive rates to the amount of available resources. The team in the new study expanded on that by creating more complex ones that also account for body size. Such models managed to better simulate animals’ ecological fate, and gives a better reading of their extinction risks. 

Not only that, but they provided the team with a much more accurate depiction of ecosystems as well. In that manner, they revealed why most animals tend to evolve larger body sizes over time.

Species survival rates are typically predicted by an energy threshold. That is, if a species does not consume enough resources, they will have trouble increasing their population size. 

The new work built on that idea by showing that smaller animals can maintain larger populations, while larger ones are more stable in smaller numbers. As a result, larger-bodied creatures do better from an evolutionary standpoint. The team found that an animal 2.5 times the size of an African elephant would have the best chance of survival in the wild because it would be the least likely to starve.

While the models are not perfect — they do not properly account for predation — they do account for a wide range of ecological factors that other such models ignore. There is still room for improvement, but the team hopes that they will provide a baseline that future studies can build off of.