At https://phys.org/news/2023-06-lost-giants-reveals-decline-abundance.html … the diversity and abundance of elephants in Africa was much greater in the past. Using fossil evidence a new study looks at past animal size and the number of animals alive and thriving. As such, they claim to challenge assumptions about the cause of megafaunal extinctions in Africa. By this phrase they mean the well drilled theory that it was all down to human hunters – especially at the end of the Ice Age. This idea is inextricably linked to the use of models – and the limited input into those models.
Fossilised teeth play a big role in the study. The researchers say they found evidence for decreasing number coinciding with increasing size, which appears to fit into pre-conceived opinion. It is known as ‘metabolic scaling’ and does have merit as large size is not a continuous process, but ebbs and flows. Some elephants reached a size of ten tons – unparalleled in the modern world. The loss of these large animals is coeval with the end of the Pliocene, and again at the end of the Pleistocene, for example. Today’s animals are miniaturised, it would seem.
The big surprise came with size abundance distribution and how it changed over time. Communities of animals living more than 4 million years ago had a higher number of large animals – and their disappearance did not just happen at the end of the Ice Age. The study outcome says the loss of African elephants took place long before humans played a significant role – although there was an extensive event in the Late Pleistocene that was followed by human expansion during the Holocene. Megafaunal losses occurred much earlier – in Lste Pliocene for example. However, at no point is catastrophism featured. It is as if it did not and could not happen. It would explain the end of Pliocene and end of Pleistocene die-offs.
In similar vein, at https://phys.org/news/2023-06-giant-tree-kangaroos-unexpected-australia-major.html … we have giant tree kangaroos living in wider regions of Australia, in what are now dry and desert like environments. Currently, these dimunitive animals live in the tree canopy of tropical forest in Queensland and New Guinea. However, they were once endemic right across most of Australia. They were also, very often, much greater in size. They too thrived in the Pliocene – and they too were effected by whatever brought the end of the Pliocene to a close. They, like African elephants, also survived into the Pleistocene – with modifications.