Even the biggest animals in the world today are no match for dinosaurs. But could land mammals evolve and get as big? In a new study, experts point out that these animals cannot develop bodies as large as the largest dinosaurs because they have to use so much of their physical energy.
The aim of the research was to revisit key questions about size, specifically in mammals. The researchers’ argument is that size impacts everything from reproduction to extinction, and mammals are a good test case, as there’s a lot of variation.
Researchers say that during the Mesozoic, mammals were small. After dinosaurs became extinct, mammals evolved to be much larger as they diversified to fill whatever ecological niches became available.
Having so many different lineages independently evolve to similar maximum sizes suggests that there were similar ecological roles to be filled by giant mammals around the world, and the biota in all regions were responding to the same ecological constraints.
However, scientists point out that mammals are called endothermic, which means that they regulate their own body temperature. A mammal of a given size expends ten times more energy than a reptile or dinosaur of the same size. Dinosaurs, like reptiles today, did not regulate their body temperature and the extra energy allowed them to grow.
Source: University of Georgia via IFL Science
