In a warming world, many species, including modern-day humans, could become smaller to survive.
“That’s not to say every species of mammal would get smaller, but it seems to be a common survival trick of mammals when temperatures spike pretty quickly,” Brusatte told The Guardian. “Which does raise the question: if temperatures do spike really quickly might humans dwarf, might humans get smaller? And I think that’s certainly plausible.”
A 2021 study found relationships between temperature and body size, although it also found that temperature had no effect on brain size. Still, some experts are skeptical that warming temperatures will cause humans, or even other mammals, to evolve to be smaller, noting that resource availability is more likely to have an impact.
“We are not really controlled by natural selection,” said Adrian Lister, a palaeobiologist at the Natural History Museum in London. “If that was going to happen, you’d need to find large people dying before they could reproduce because of climate warming. That is not happening in today’s world. We wear clothes, we have got heating, we have got air conditioning if it is too hot.”
Whether or not humans shrink, Brusatte says our species has been detrimental to other animals. “I think if you were a rhino, an elephant, a lion, a platypus, a koala, you probably would want humans to be gone,” he said. “But hopefully that’s not going to happen.”
Source: The Print