Science - USA (2022-04-22)

360 22 APRIL 2022 • VOL 376 ISSUE 6591 science.org SCIENCE

IMAGE: JULIUS T. CSOTONYI/SCIENCE SOURCE

By Victoria Arbour

S

ixty-six million years ago, the begin-

ning of the end of the age of dino-

saurs came crashing down in the

form of a Mount Everest–sized as-

teroid that struck what is now the

Yucatán Peninsula in Mexico. It is

a familiar end to many popular dinosaur

books, documentaries, and other me-

dia published since the 1980s, when

the asteroid impact hypothesis began

gaining ground as the driver of the

end-Cretaceous mass extinction. But

the details of this cataclysmic event,

and what happened afterward, have

rarely received the feature-length

treatment that Riley Black presents

in The Last Days of the Dinosaurs: An

Asteroid, Extinction, and the Begin-

ning of Our World.

In just over 300 pages, Black pulls

together decades of scientific re-

search on the demise of the nonavian

dinosaurs into a deeply compelling

narrative of both luck and misfor-

tune in the face of almost unimagin-

able calamity. Major advances over

the past 15 years in particular have

enhanced our understanding of

the end of the Mesozoic era and its

mass extinction, making this a timely

and distinctive addition to the ever-

expanding landscape of popular sci-

ence dinosaur books.

Starting just a few days before the

asteroid impact, Black centers the

story on the animals present in the

Hell Creek Formation of the western

United States, a geological unit that

has been extensively studied for more

than 100 years and that provides the

best window we have into the time

before and after the mass extinction.

Through the eyes of the inhabitants

of Hell Creek, readers pass through the mo-

ment of impact and then the first hour, day,

month, and year of the Cenozoic era.

The story continues with chapters set

one hundred, one thousand, one hundred

thousand, and one million years after the

asteroid impact, charting the slow but

steady reshaping of the world. The final

chapter includes a visit to a geological site

preserving markers of the impact itself and

reflections on the nature of mass extinc-

tion and what lessons humanity can take

away from this singular event. Each chap-

ter ends with a detour to somewhere else

on the planet—Antarctica, India, and the

Atlantic Ocean, for example—providing a

global balance to this otherwise tightly fo-

cused narrative.

Unlike the other mass extinctions re-

corded in the fossil record, extinction for

most species at the end of the Cretaceous

probably happened within a few hours or

days after the asteroid impact. Black’s writ-

ing captures the horror of the impact event

without lingering on doom and gloom,

instead keeping a steady momentum fo-

cusing on survival and change. The Last

Days of the Dinosaurs emphasizes the lim-

its of adaptation and natural selection in

the face of abrupt environmental change,

highlighting how this singular event cre-

ated a powerful filter that favored the

small and unfussy over large and special-

ized creatures.

Many of the main players in the

book’s first few chapters—Tyranno-

saurus, Triceratops, and Ankylosau-

rus, to name a few—will be familiar

to most readers. But the animals often

overshadowed (metaphorically and

literally) by dinosaurs are given some

much-deserved attention here, too.

Black recounts stories of lucky sur-

vivors whose descendants will be fa-

miliar to many readers—frogs, snakes,

turtles, and crocodiles—and organ-

isms that rarely get a mention in di-

nosaur stories, such as the planktonic

coccoliths and coil-shelled ammo-

nites. And of course, as the nonavian

dinosaurs pass into history, we see the

changes that happen to the ancestors

of today’s mammals, who evolved into

new forms in the empty spaces cre-

ated by the asteroid’s aftermath.

Instead of extensively annotating the

text with footnotes or citations, Black

provides a welcome appendix summa-

rizing the evidence used to build the

stories told in each chapter. This keeps

the text flowing without interruptions

while still making clear the limits of

current scientific evidence and where

informed speculation fills in the gaps.

Detailed notes close out the book, with

references to primary literature for

those who want to dig deeper. Each

chapter also includes charming illus-

trations of that chapter’s main “pro-

tagonist” by artist Kory Bing.

The Last Days of the Dinosaurs would fit

equally comfortably on the bookshelf of a

die-hard dinosaur enthusiast, someone re-

visiting their childhood love of dinosaurs

or paleontology, and anyone interested

in the science of extinction or the transi-

tion from the age of dinosaurs to the age

of mammals. j

10.1126/science.abo7409

PALEONTOLOGY

Inside the dinosaurs’ demise

A science writer offers an accessible account

of the Mesozoic’s mass extinction

The Last Days of the

Dinosaurs: An Asteroid,

Extinction, and the

Beginning of Our World

Riley Black

St. Martin’s Press,

2022. 304 pp.

A marsupial traverses a branch above a Pachycephalosaurus

in this artistic rendering of the dinosaurs’ last days.

INSIGHTS | BOOKS

The reviewer is curator of paleontology at the

Royal BC Museum, Victoria, BC V8W 9W2, Canada.

Email: [email protected]