Book review – Page 2 – Hoopoe

Book review: The Rise and Reign of the Mammals

***** Epic in scope and majestic in execution
Leon Vlieger, NHBS Catalogue Editor

Imagine being a successful dinosaur palaeontologist and landing a professorship before you are 40, authoring a leading dinosaur textbook and a New York Times bestseller on dinosaurs. Imagine achieving all that and then saying: “You know what really floats my boat? Mammals.” After the runaway success of his 2018 book The Rise and Fall of the Dinosaurs, palaeontologist Stephen Brusatte shifted his attention and now presents you with the follow-up, The Rise and Reign of the Mammals. Taking in the full sweep of mammal evolution from the late Carboniferous to today, this book is as epic in scope as it is majestic in execution.

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 recognise 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 unrealised 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).

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.

Brusatte’s strength is to bring to life the above flurry of names. What kind of creatures were they? And how can we deduce this from fossil evidence? Somewhere between chapters 6 and 7, I became awestruck by his narrative as the enormity of the mammalian evolutionary trajectory started to come into full view: bats, elephants, South American native ungulates (origins: uncertain), metatherians migrating to Australia and spawning a spectacular marsupial radiation, grazers diversified as grasses went global, and somewhere at the end, hominins evolving and repeatedly spilling out of Africa, contributing significantly to recent megafauna extinction. What a wild ride!

The macroevolutionary story is fascinating in itself, yet Brusatte makes it even better with some interesting observations of his own. We usually think of the dinosaurs as dominating the mammals, but, he suggests, this went two ways: “While it is true that dinosaurs kept mammals from getting big, mammals did the opposite, which was equally impressive: they kept dinosaurs from becoming small” (p. 95). Furthermore, DNA studies suggest that many modern mammal lineages originated back in the Cretaceous. But where are the fossils? Could some of the poorly understood archaic placentals such as condylarchs, taeniodonts, and pantodonts be the missing fossils that we have not yet been able to link to modern groups because of the lack of signature anatomical features? Excitingly, Brusatte is part of a research consortium that is building a master family tree based on both anatomy and DNA.

As in his last book, Brusatte excels at explaining complex research methods and scientific concepts. One example is Tom Kemp’s concept of correlated progression. Several times during early mammal evolution, a whole suite of anatomical, behavioural, and functional traits were changing together, making it hard to unravel what was driving what. For instance when cynodonts shrunk in size and changed their growth, metabolism, diet, and feeding styles. Then there is the revision of the mammal family tree based on DNA sequencing. The classic tree, championed by zoologist George Gaylord Simpson in 1945, was based on anatomical features. By the early 2000s, DNA-based genealogies suggested that many supposed relationships were actually cases of convergent evolution, resulting in a new classification that reflected geographical patterns rather than anatomy. The new groupings came with some tongue-twisting names: Afrotheria, Xenarthra, Laurasiatheria, and Eurarchontoglires. A final example is tooth morphology, an important diagnostic trait in this story.

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.

In what is surely a hallmark of his love and enthusiasm for the field, Brusatte’s bibliography has again been written as a narrative. It is like a chatty literature review in which he recommends books and papers, indicates where literature has become outdated, adds more technical details or clarifications, discusses where there is active debate and disagreement, and shortly touches on topics that he had to omit from the main narrative. Yes, this takes up more space than a regular reference section, and I am sure it is more time-consuming to write, but it is ever so useful. You could not wish for a better starting point if you wanted to read deeper into the technical literature.

Finally, you might be left wondering how this book compares to Elsa Panciroli’s Beasts Before Us which covered early mammal evolution up to the K–Pg extinction. There is overlap here in more than one way; Brusatte co-supervised her PhD project describing the docodont Borealestes from a Scottish fossil. I was therefore mildly surprised that he does not mention her book. There is some inevitable overlap as both books walk through the same groups, though Brusatte provides a fuller picture by covering mammal evolution up to today. Panciroli’s book stands out for its fantastic writing, though, so you cannot go wrong by reading them both.

The Rise and Reign of the Mammals is a more-than-worthy successor to The Rise and Fall of the Dinosaurs. Brusatte convincingly shows that the evolutionary story of mammals is just as fascinating—if not more so—as that of the dinosaurs.

Book review: What an Owl Knows

***** A hoot of a book
Leon Vlieger, NHBS Catalogue Editor

Owls are one of the most enigmatic groups of raptors, in part because there is so much we still do not understand about them compared to other birds. Nature writer Jennifer Ackerman previously wrote the critically acclaimed The Genius of Birds. In What an Owl Knows, she reveals the creature that hides under that puffy exterior, peeling back the feathers layer by layer to show our current scientific understanding of owls. She has interviewed scores of scientists and owl aficionados as part of her background research, making this as much a book about owls as about the people who study and love them. A captivating and in places touching science narrative, this book is a hoot from beginning to end.

Owls are everywhere in the human imagination and, Ackerman argues, have always been: “We evolved in their presence; lived for tens of thousands of years elbow to wing in the same woods, open lands, caves, and rock shelters; came into our own self-awareness surrounded by them; and wove them into our stories and art” (p. 235). For all that, their nocturnal lifestyle makes them hard to study and they have long been—and in many places still are—wrapped in superstition. Ackerman dedicates a chapter to such beliefs and the harms that frequently flow from them. Fortunately, the tide is turning. Thanks to the tireless efforts of a dedicated cadre of scientists, conservationists, and numerous volunteers, a far more fascinating creature emerges from the contradictory tangle of ideas that humans have held about owls.

A red thread that has been subtly woven through this book is the importance of understanding animals on their terms. Ed Yong’s An Immense World is one recent example of this welcome trend amongst science writers and Ackerman appropriately starts with a chapter on owl sensory biology. What is it like to be an owl? Though this question can never be fully answered, that should not stop us from trying our hardest. Vision and hearing are obviously important to owls but the book has plenty of surprises up its sleeve once you start digging into the details: from the magnificent facial disk that acts somewhat like a parabolic reflector to gather sound, a hearing system that does not seem to age, to the fact that owls can see ultraviolet light. At night. With rod rather than cone cells (like pretty much every other bird).

The same question motivates research on owl vocalisations as “a hoot is not just a hoot” (p. 81). Owls utter a profusion of yaps, squawks and warbles and Ackerman paints a lively portrait in words. Barn owls have “a raspy hiss that sounds like a fan belt going out on your car” (p. 82), while the tiny Flammulated Owl breaks the link between body size and vocal pitch, sounding like “a big bird trapped in a small body” (p. 82, quoting ornithologist Brian Linkhart). These sounds can reveal an awful lot about the individual owl and its relationship with other owls in the landscape. Ackerman criticises some of the research on owl intelligence. They cannot pass the string-pulling test, a common test in ethological research in which an animal has to pull on a rope to reel in food that is out of reach. The idea is that it tests an animal’s understanding of cause and effect. But is this a fair test or does it “point to the limitations of our definitions and measures of intelligence” (p. 261)?

The most intimate insights have come from rescued owls that can no longer be returned to the wild. Many researchers have ended up caring for an individual and becoming intimately familiar with them. Gail Buhl, a leading authority on training rehabilitated captive owls, here explains five important things that she has learned. One particularly poignant observation is that owls might appear calm and stoic around humans, but having paid close attention to their body language, Buhl concludes that “they’re experiencing the same stress as other raptors, but they’re internalising it” (p. 228). This has major consequences for how even well-intended trainers and rehabbers ought to behave around owls. “We need to treat them not as mini-humans in feathers, but as their own entity” (p. 231), Ackerman writes, before throwing in a beautiful quote from naturalist Henry Beston. In his words, wild animals “are not brethren, they are not underlings; they are other nations, caught with ourselves in the net of life and time” (pp. 231–232).

Following on directly from her last book on bird behaviour, there are fascinating chapters here on the behaviour of owls: their courtship and breeding, their parental behaviour, their roosting, and their migration. Yes, many owls are migratory and some species can cover surprising distances. Ackerman makes a fantastic case for the value of long-term monitoring programmes to establish reliable population estimates. This is vital data for conservation efforts and is often missing. And sometimes what we think we know is wrong, as in the case of the Snowy Owl. Where initial estimates put the global population at some 200,000 birds, satellite tracking has revealed that they are actually a single population moving around the whole Arctic Circle, resulting in duplicate counts. Revised estimates now put the figure at a mere 30,000 birds.

Ackerman relies on the input of numerous scientists and volunteers. As such, this is as much a book about the people who study owls. I was delighted to hear more from Jonathan Slaght (his book Owls of the Eastern Ice is magnificent). Other stories tug on the heartstrings and none more so than that of Marjon Savelsberg. A Dutch musician trained in baroque music, her dreams came crashing down when she was diagnosed with a heart condition that consigned her to a mobility scooter. When she stumbled on the website of the Dutch Little Owl Working Group, she quickly became one of their most active volunteers, revealing a skilled ear for analysing owl calls. Suddenly, she had a new career and a new group of appreciative ecologist colleagues: “[I] realised I was still a musician. All the skills that I learned, all the talent I have, I can still use, just in a different way” (p. 105). It is a powerful story of redemption-by-owl.

Ackerman carefully balances these two facets: the scientific insights that she has carefully distilled from research papers and interviews, and the personal stories of those who study and love owls. As a result, What an Owl Knows is compulsively readable and readily accessible for those who lack a scientific background in ornithology.

You might also be interested in reading our Q&A with Jennifer Ackerman in which we discuss owls’ reputation for wisdom, the incredible research that is shedding more light on their lives, and the mysteries that still remain.

Book review: Otherlands

***** A spine-tingling debut
Leon Vlieger, NHBS Catalogue Editor

Our planet has been many different worlds over its 4.5-billion-year history. Imagining what they were like is hard – with our limited lifespan, deep time eludes us by its very nature. Otherlands, the debut of Scottish palaeontologist Thomas Halliday, presents you with a series of past worlds. Though this is a non-fiction book thoroughly grounded in fact, it is the quality of the narrative that stands out. Beyond imaginative metaphors to describe extinct lifeforms, some of his reflections on deep time, taxonomy, and evolution are simply spine-tingling.

The 16 chapters in Otherlands, each accompanied by a gorgeous illustration from Beth Zaiken, step back in time by millions or even tens of millions of years to visit a place on Earth and describe its ecosystems and organisms. Halliday includes well-known sites such as end-Cretaceous Hell Creek (66 million years ago, or mya) or Lagerstätten such as the Cambrian Chengjiang biota in China (520 mya). Far more interesting are the little-known eras and places such as the Italian promontory of Gargano during the Miocene Messinian Salinity Crisis (5.3 mya), the sweltering warmth of Seymour Island in Antarctica during the Palaeocene-Eocene Thermal Maximum (41 mya), or the underwater life around the Silurian Yaman-Kasy vent in Russia (435 mya).

Stylistically, Otherlands is a narrative non-fiction book. What that means is that, though everything is grounded in fact, Halliday does not get lost in the details. Where competing hypotheses exist he picks one and runs with it, rather than detailing the academic debates and different schools of thought. It is a stylistic choice that I can get behind given the quality of the writing that follows.

Because make no mistake, Halliday knows how to craft captivating prose. He won the Hugh Miller Writing Competition in 2018 and the John C. Marsden Medal from the Linnean Society for the best doctoral thesis in biology in 2016. Reading Otherlands, it is easy to see why. I do not know what they feed Scottish palaeontologists, but I was reminded of Elsa Panciroli’s Beasts Before Us. Let me back up my enthusiasm with some quotes that can only touch on a fraction of what is on offer.

There are the obvious imaginative metaphors to describe animals. The Triassic gliding reptile Sharovipteryx mirabilis (225 mya) is imagined looking rather inelegant once landed “with its membrane retracting and limbs thrown all directions like a collapsing deckchair” (p. 159), while the Ediacaran sedentary animal Dorothy’s Rope (550 mya) resembles upright towers “composed of bulges like knotted rope, as if Gaudi had designed an industrial town” (p. 277). Other descriptions are more poetic. Basilosaurids, the first fully aquatic whale ancestors in the Eocene (41 mya), have yet to evolve the melon organ. They “can listen to the music of the oceans, but they have not yet learned to sing” (p. 86).

Particularly powerful are his reflections on deep time. A recurrent theme in this book is that of impermanence: “gatherings of species in time and space may give the illusion of stability, but these communities can only last as long as the conditions that help to create them persist” (p. 18). Some ecosystems never return. The long-lived Jurassic crinoid colonies (155 mya) that made a home on floating logs blown into the sea during storms disappeared when the evolution of shipworms made “this way of life impossible, something that can and will never be replicated in quite the same way again; wood just doesn’t float for as long as it used to” (p. 151). And while the world feels old in our day, it is easy to forget the world was already old in the deep past. The mountains of the Triassic (225 mya) “are built from the deep sea”, within which can be seen “the coils and shapes of the long-extinct creatures of the Carboniferous seas, well over 100 million years old even now” (p. 158).

What made my hair stand on end were Halliday’s reflections on phylogenetics, the evolutionary relationships between animals. I love how he drowns scientific concepts in poetic language. Take the Paleocene Baioconodon (66 mya). Beyond one of the earliest placental mammals, we do not really know what it was. “Their anatomy is too non-committal, too similar to and yet too distinct from too many living orders to be placed with confidence. […] They are an unspecialised, Platonic placental, a lump of living clay from which all others are stretched, pinched and pulled into shape” (p. 105). We cannot even describe its young as kits or calves: “it does not yet make sense to talk of cattle or dogs, of monkeys or horses. None of these groups exist yet […] names lose tangibility in the depths of the past, and our language has no description for the young of common ancestors” (p. 104). You start to see why Halliday wrote his way backwards from the present. He makes a similar observation about the Ediacaran biota. Alien to us, “they are aberrant only from a modern perspective” (p. 282). Our confusion is partially because “we are trying to define them the only way we can: on the basis of those few survivors to have found paths to the present”, while the dead-end branches “by the simple fact of having not survived, forfeit a common name” (p. 283).

Similarly spine-tingling are his explanations of evolutionary processes. Species names are artificial designations for a continuous phenomenon. The way palaeontologists deal with this can be compared to rivers. Just as a river can split and its two branches be called by two names from that point in space forward, so can a species that spatially separates be called by two names from that point in time forward. And why did so many higher taxa appear during the Cambrian explosion? One idea is that, once in place, fundamentals cannot be changed easily: “evolution today can only be played within the constraints set by the past”. Another idea is that “there is nothing intrinsically impossible about a new body plan developing today, were it not for the existence of others”. Gould wrote of filling the ecological barrel and Halliday puts it thus: “establishing the basic roles within an ecosystem is like adding large rocks into a barrel […] evolutionary processes […] adding in finer and finer divisions of ecological processes, pebbles and sand falling into the barrel between the gaps left by the larger stones, structures built on other structures” (p. 258). Not only does this ring true, but it is also truly beautiful language.

Otherlands is an exceptional debut that can be savoured like a fine wine. I found myself reciting passages to anyone within earshot. Beyond a fascinating tour of extinct lifeforms, Halliday’s carefully crafted yet poetic descriptions of scientific concepts are a masterclass in spellbinding science communication.

You might also be interested in our Q&A with Otherlands author Thomas Halliday where we discuss the book and the process of writing it, our endless fascination with dinosaurs and the lessons we might learn from studies of deep time.