Copy-pasted summary, with emphasis added:<p>&quot;The demise of the giant ape Gigantopithecus has been the focus of recent study, where researchers have reached the conclusion that the presumably largest apes in geological history died due to their <i>insufficient adaptability</i>. Analyses of fossil tooth enamel show that <i>the primates were restricted to forested habitats</i>.&quot;<p>So, the forest turned into savannah faster than they could adapt. Similar things happened and happens to zillions of species.