The Ice Age, or Pleistocene epoch, is known in Earth\u2019s history as the\nera when giant mammals (megafauna) dominated ecosystems. Animals such as\nthe woolly mammoth, woolly rhinoceros and steppe bison became icons of\nthe harsh, cold environment. This phenomenon of extraordinarily large\nbody size raises fundamental questions about the evolutionary factors\nthat drove their emergence.<\/p>\n
Palaeontological research reveals that gigantic body size did not\nappear instantaneously. This evolution was a long process that began\nafter the extinction of the dinosaurs around 66 million years ago.\nWithout the dominance of large reptiles, mammals began to diversify to\nfill the empty ecological niches. Studies show that the maximum body\nsize of land mammals increased gradually over millions of years,\nreaching its peak in the late Pliocene and Pleistocene periods.<\/p>\n
The environmental conditions of the Ice Age \u2014 which tended to be\ncold, dry and fluctuating \u2014 imposed certain evolutionary pressures. A\nlarge body offered several crucial biological advantages for\nsurvival:<\/p>\n
Although the climate at the time was extreme, Ice Age ecosystems were\nable to support a very high biomass of herbivores. Research on the Last\nGlacial Maximum period shows that large herbivores were able to utilise\ndry grasses as a food source efficiently. This created a cycle in which\nthe environment could sustain significant populations of large\nanimals.<\/p>\n
However, gigantic body size was also a double-edged sword. Large\nanimals required a very high energy intake to survive. Research on food\nwebs in the Americas shows that the largest species often lived at the\nthreshold of their energy requirements.<\/p>\n
This dependence on vast amounts of energy made them highly vulnerable\nto environmental change. Towards the end of the Pleistocene, a\ncombination of drastic climate change, habitat shifts and pressure from\nhuman activity caused population declines that ended in the mass\nextinction of megafauna. The evolution of gigantism proves that large\nsize was an advantage during periods of environmental stability, but\nbecame a fatal weakness when natural conditions changed radically.\n(Source: Nature Ecology)<\/p>", "url": "https:\/\/jawawa.id\/newsitem\/why-were-ice-age-animals-giant-sized-an-evolutionary-explanation-1788767462", "image": "" }, "sponsor": "Okusi Associates", "sponsor_url": "https:\/\/okusiassociates.com" }