Beasts Before Us

Title: Beasts Before Us – The Untold Story of Mammal Origins and Evolution

Author: Elsa Panciroli

Publisher: Bloomsbury Sigma, 2023 (First)

ISBN: 9781472983985

Pages: 320

 

We are really awed by our planet’s collision with an asteroid at the end of Cretaceous period 65 million years ago when dinosaurs became extinct. The demise of this predator group prepared the ground for mammals to explore and conquer all possible niches on earth. As a result, mammals grew in size, became more and more diurnal and won the competition for scarce resources. Eventually, a bipedal ape which developed a large brain size took over the world and assumed nature’s role in making several species go extinct. This has been the accepted lore regarding the development of mammals – and by corollary, of humans too. This book presents a different view, one in which it is conclusively shown that mammals existed and to a certain extent were spread over the face of the earth much earlier than thought. What it paints is the picture of a see-saw. Mammals proliferated in the Permian but were seriously put back by the mass extinction at the end of the era. Reptiles, which include dinosaurs, took prominence in the Triassic period which followed it. Then came the asteroid at the end of Cretaceous and mammals again held sway which still continues. This interesting story is told by Elsa Panciroli, who is a Scottish paleontologist who studies the evolution and ecology of extinct animals. She is an experienced science communicator and has written for mass-media houses.

 

The author discusses on the so called ‘success’ of a species in biological parlance. In fact, this is not to be confused with the dominance of a species on others. The term ‘success’ generally means only that it could propagate itself over time in an uninterrupted lineage. In that sense, all species living today are successful up to now. Moreover, while there are only 5,500 species of mammals, there are 18,000 species of bird and 35,000 of fish. That’s just vertebrates. There are over one and a half million species of beetles. So, who is the most successful? This should be kept in mind while making tall claims such as this was the ‘age of mammals’. The only thing is that mammals include the largest vertebrates and we are disproportionately focused on size. However, they originated much earlier than the current consensus. Paleontology suggests that they arose 350 million years ago in the supercontinent of Pangaea. Around 300 million years ago, mammals parted ways with reptiles. Mammals did not evolve from reptiles; they only shared a common ancestor. The belief that mammals followed reptiles in dominance of the world became prevalent as most of the early fossil evidence found in Europe came from secondary rocks and belonged to reptiles. After a catastrophe, they were wiped out and mammals appeared in the tertiary age. The first fossil of a mammal ever found was the jaw of an opossum-like animal discovered in 1820 in secondary rocks. With more evidence coming from all over the world, the scientific world has now conceded that mammals existed and flourished much earlier than the age of reptiles.

 

The author narrates personal experiences of prospecting for fossils in her native Scotland, Russia and South Africa. Mongolian expeditions of the pioneer paleontologist Zofia Kielan-Jaworowska are given in some detail as she had obtained the largest collection of Cretaceous mammals. The fossils demonstrated that the age spanning 250 million years before the collapse of dinosaurs which was the first age of mammals was ignored by scholars for a long time. Early mammals like pelycosaurs looked like reptiles. We continue to see descriptions like mammal-like reptiles to describe them. From among the ranks of the pelycosaurs, a new group emerged which developed the key traits we associate with modern mammals including warmer blood and higher energy lifestyles. They also established – for the first time – an ecosystem which we still recognize today as based on large numbers of herbivores fed upon by a smaller cohort of carnivores. These cyanodonts are the ancestors of mammals which looked more like compact dogs with increasingly enlarged and complex jaw muscles. This change is linked to chewing with more complex teeth. At the same time in the Late Permian, 252 million years ago, reptiles and other tetrapods were also proliferating. Some of them had also evolved into giants. They would get their lebensraum when mammals were most hardly hit by the end-Permian extinction event.

 

The Permian extinction was a great cataclysm in the life of biota on our planet. Around 250 million years ago, volcanic activity peaked in the region which is now in Russia which threw up volcanic ash and greenhouse gases in huge quantities as to alter the global climate for millions of years. Three quarters of life were wiped out and the next age – the Triassic – began with a slate wiped clean. Reptiles and dinosaurs gained prominence and grew to large body sizes. But the mammals were not always at the receiving end however. We have found evidence of carnivorous mammals of this era that ate baby dinosaurs for food. In late-Triassic, little mammals the size of a mouse spread across the globe. These little creatures are thought to be the ancestors of us all. Warm-bloodedness helped early mammals to become nocturnal and escape the unwelcome attention of larger predators. The coldness of night is no barrier to an animal carrying its own heating system. Most of the mammals (except humans, of course) have only mediocre ability to distinguish vivid colours and their eyes are more attuned to see shapes in the dark. It is surmised that humans and primates re-acquired the ability to see colours through a mutation in the genes, but their ability is still a far cry from the glorious visual world of birds. Because they adapted as nocturnal animals, the sense of smell and sound greatly developed in mammals.

 

Whether intended or not, this book not only fails to discredit Lamarck’s use and disuse theory as the reason for causing genetic changes in organisms, but on at least two occasions, it lends a gentle support to it. In a footnote on page 31, the author claims that ‘the characteristics that were used would be passed on, and those that weren’t would atrophy which isn’t all that far off the mark’. This is indeed far off the mark. Lamarck’s theory stayed afloat in the pre-genetics era when the mechanism of inheriting a parent’s characteristic by the offspring was unknown. I’m sure the author is well aware of this and obliquely suggests natural selection as the mechanism that helped propagate features advantageous to survive in a particular habitat, but some readers may get confused here and think that Lamarck’s idea must have something in it. Another argument on the same line is the adaptation of herbivores to digest plant matter by incorporating helper bacteria colonies in their guts. Panciroli argues that microorganisms may have initially been ingested by early tetrapods when they ate some decomposing plant matter. Eventually, some of the plant-processing bacteria survived in the gut and a symbiotic relationship developed. This too is a broad statement enough to perplex a reader on how this new feature persisted in a new generation of the animal. This book introduces flowering of plants as a novel mechanism of species propagation developed around 120 million years ago that helped in mammal evolution. Earlier, pollination was limited through wind and water. Another interesting feature is the remark on ancient human bones. Analysis of the bones between the Neolithic and bronze ages (which is just yesterday by paleontological timescales covered elsewhere in the book) shows that the intense manual labour of early farming lifestyles made the average woman develop upper body strength comparable to a renowned modern athlete. Life was really hard back then..!

 

It is asserted that we are seeing a radical transformation in the study of paleontology and that is part of the reason for writing this book. Use of statistical methods to analyse big data and the routine CT scanning of fossils have opened up entirely new fields of research. In fact, Panciroli is very forceful – even to the brink of obsession – in boasting about the use of modern technology and mathematical tools used by her and her colleagues around the globe. This may be an attempt to enhance the stature of paleontology in the minds of young readers and to attract them to its study. It’d be a good exercise for the readers to look up the mentioned animals on Google as the included photographs and illustrations are totally unappealing. A real turnoff is the author’s punctilious political correctness that often leaps off the pages to sting you in the eye. She frequently flays white European bias towards discrimination of local knowledge regarding finding fossils. She credits nameless native inhabitants, than the person who described it to the world. This is mere showiness. She accuses the big names in her specialty of research of having harboured racist views on ethnicity and a misogynist perspective of history. As a successful woman typically considers herself a feminist by right, the author stresses on the contribution of earlier women in elevating paleontology to a widely respectable avenue of study. She accuses male bias in history and science and goes as far as claiming the same bias in museum specimens since we often see the peculiar features of the male displayed in such institutions! At the same time, she points out amusingly that the term ‘mammals’ applied to a wide group of animals, is not gender-neutral.

 

The book is recommended.

 

Rating: 3 Star