Mammals shared our planet with the dinosaurs throughout their long reign, from the initial split of our amniote common ancestor into synapsids (us) and diapsids (them), to their extinction at the end of the Cretaceous. Over the course of some 100 million years, a parade of lineages evolved—archaic mammals all—piecemeal developing the traits we recognize as mammalian today: pelycosaurs, therapsids, cynodonts, mammaliaformes, docodonts and gliding haramiyidans, multituberculates, and therians who gave rise to today's placentals, marsupials, and monotremes. However, the above must not be mistaken for a linear march of progress. "[M]ammals were a still unrealized concept, which evolution had yet to assemble" (p. 20). Simultaneously, it does not behove us to call these now-extinct groups evolutionary dead ends. "In their time and place, these mammals were anything but obsolete" (p. 88). A whirlwind tour of mammal evolution. … Brusatte’s deep knowledge of the fossil record creates a rich tapestry in which each thread is a mammalian lineage. These interwoven threads dip in and out intermittently and sometimes disappear altogether in the finality of extinction, but those that remain always unspool in a bright burst of color to fill the gap.” — Science There is plenty of science in this book, and Brusatte doesn’t skimp on the use of those incredibly complicated animal names, but he adds just enough personal anecdotes and downright story telling to keep the narrative going. His highly fictionalized but factual tale of the little pregnant mini horse who fell into a lake and became a fossil is a delight. So is his encounter with a legendary Polish bone digger. His explanation of the infamous asteroid extinction event 66 million years ago, and other less catastrophic but life altering incidents, are so well told I listened to them twice.

With the extinction of the dinosaurs, the rise of mammals turned into a reign. Isolated on various land masses after the supercontinent Pangaea had fragmented, they were poised for a slow-motion taxonomic starburst that would play out over the next 66 million years. In the northern hemisphere, placental mammals replaced multituberculates and metatherians and rapidly evolved into primates and the odd- and even-toed ungulates. The latter two evolved giants: brontotheres, chalicotheres, and cetaceans. I had a similar reaction to The Rise and Reign of the Mammals, paleontologist Steve Brusatte’s sweeping history of the animals that have, for the moment, inherited the Earth. Moving generally forward in time, the book describes how the mammalian line progressively acquired a range of features that have come to define what a mammal is. The epic story of how our mammalian cousins evolved to fly, walk, swim, and walk on two legs [...] [Brusatte's] deep knowledge infuse[s] this lively journey of millions of years of evolution with infectious enthusiasm." At some point, two populations of these lizard-like creatures became separated from each other. And the rest is history.Dr. Brusatte starts his book in the Permian Era with what used to be called the “mammal-like reptiles”, although he explains that term is no longer used as the animals concerned were not actually reptiles (although they certainly look like reptiles). “Stem mammals” is the phrase now favoured. Probably the spectacular looking predator Dimetrodon is the most famous of these animals, although its direct line did not survive, so sadly none of us can claim a Dimetrodon as one of our ancestors. Out of this long and rich evolutionary history came the mammals of today, including our own species and our closest cousins. But today's 6,000 mammal species – the egg-laying monotremes including the platypus, marsupials such as kangaroos and koalas that raise their tiny babies in pouches, and placentals like us, who give birth to well-developed young – are simply the few survivors of a once verdant family tree, which has been pruned both by time and mass extinctions.

A tour de force, charging through 350 million years of mammalian history. ... Brusatte is a great storyteller whose infectious curiosity permeates the book. He brings to life the often strange variety of early mammals." — The Explorers Journal Humans, too, offer much to marvel at: as Brusatte points out, we are sentient apes that have changed the world. But we are only a chapter in a far bigger story. Ice Age Mammals: the cooling climate would lead to various Ice Ages and ice age mammals like the mastodons and mammoths in North America. North and South America would meet during this time, leading to a major migration of species. Other megafauna like woolly rhino and sabre tooth cats could now be found. Beginning with the earliest days of our lineage some 325 million years ago, Brusatte charts how mammals survived the asteroid that claimed the dinosaurs and made the world their own, becoming the astonishingly diverse range of animals that dominate today’s Earth. Brusatte also brings alive the lost worlds mammals inhabited through time, from ice ages to volcanic catastrophes. Entwined in this story is the detective work he and other scientists have done to piece together our understanding using fossil clues and cutting-edge technology. Some of the moments of evolutionary invention that led to what we now think of as a mammal are remarkably subtle. There’s the hard roof of the mouth that created a dedicated airway to the lungs, allowing mammal ancestors to eat and breathe at the same time. There’s the change from a spine that bends from left to right (which produces the classically reptilian side-to-side gait) to one that enables bending up and down, which ultimately allowed mammals to take in more oxygen as they moved, helping them run faster. And there’s the variety of tooth shapes — incisors, canines, premolars and molars — that made it possible for mammals to eat many kinds of food. A reptile, by contrast, tends to have just one tooth type.

But some lived. “Those that did survive happen to be the ones that were smaller, the ones that could burrow or hide more easily, and the ones that had very generalist diets that could eat lots of things,” says Brusatte.

Beginning with the earliest days of our lineage some 325 million years ago, Brusatte charts how mammals survived the asteroid that claimed the dinosaurs and made the world their own, becoming the astonishingly diverse range of animals that dominate today's Earth. Brusatte also brings alive the lost worlds mammals inhabited through time, from ice ages to volcanic catastrophes. Entwined in this story is the detective work he and other scientists have done to piece together our understanding using fossil clues and cutting-edge technology.Steve Brusatte, the author of The Rise and Fall of the Dinosaurs, brings mammals out from the shadow of their more showy predecessors in a beautifully written book that . . . makes the case for them as creatures who are just as engaging as dinosaurs.’ – The Sunday Times, ‘Best Books For Summer’ What helps with these explanations are some excellent illustrations. B/w photos show amazing fossils, Todd Marshall contributes both decorative chapter headings and explanatory artwork, and Brusatte's former student Sarah Shelley adds b/w diagrams, illustrating for instance the remarkable changes in jaw bones and how some of these were repurposed to become our inner ear bones! Woven throughout are stories of the people behind the research. Brusatte introduces both young scientists and many past scientists that are not widely known. I can remember learning in grade school science that dinosaurs ruled the earth for a while until they disappeared; then the mammals took over. Years later that perception was reinforced while visiting the Smithsonian Museum of Natural History where I noticed a small model of a fur ball on the floor next to a display of a gigantic dinosaur skeleton. As I recall there was a label next to the fur ball indicating that it represented the typical mammal during the time of the dinosaurs. We humans are the inheritors of a dynasty that has reigned over the planet for nearly 66 million years, through fiery cataclysm and ice ages: the mammals. Our lineage includes saber-toothed tigers, woolly mammoths, armadillos the size of a car, cave bears three times the weight of a grizzly, clever scurriers that outlasted Tyrannosaurus rex, and even other types of humans, like Neanderthals. Indeed humankind and many of the beloved fellow mammals we share the planet with today—lions, whales, dogs—represent only the few survivors of a sprawling and astonishing family tree that has been pruned by time and mass extinctions. How did we get here? The manner in which he tells the story, our story, is nothing short of prosaic prose transformed into poetry. ... Brusatte presents a myriad of facts about todays’ mammalian cohabitors of our planet that will whet your appetite and fire up your imagination.” — Times of Israel