The Secret History of Sharks: The Rise of the Ocean’s Most Fearsome Predators
467 pp., Ballantine, 2024
John Long
Dr. John Long, an Australian paleontologist, has gifted us
with the most complete and up to date book on shark evolution for non-specialists.
Written in an informal but precise style, the book is information-packed,
clear, and an enjoyable read if you’re into this ancient lineage of apex
predators.
Long explains the origin of sharks is still a little fuzzy, but by 400 MYA the sharks had established a lineage that continues today: older than reptiles, mammals, flowers, or trees. While he tells many interesting stories of fieldwork, nothing tops the way Chinese scientists found the oldest near-complete shark, Sehnacanthus. They were relaxing, “play-fighting,” and one “kung-fu kicked another into a roadside cliff face.” A rock fell down, split open, and there it was.
As a placoderm enthusiast, I especially enjoyed the chapter
dedicated to the competition of the Devonian era. Hundreds of species of
armored fish, most famously the awesome “dark lord” Dunkleosteus terrelli,
ruled the Age of Fishes, but Long shows the sharks were doing more than staying
small and keeping a low profile. Long before the twin extinctions that ended
the era and the placoderms, they were growing and diversifying, with the
20-foot Ctenacanthus rivaling Dunkleosteus itself in size. (Long
notes the traditional sizing of the Dunk at up to 29 feet and the recent
Engelman estimate of closer to 14 feet.)
After the Devonian, the sharks flourished, using what Long
calls its superpowers. These include the development of electroreception and the
evolutionary flexibility to develop new types of scales, teeth, and other
features. Sharks also invaded freshwater: there are few freshwater sharks
today, but at one time they were numerous and varied. The bizarre tooth-whorl Heliocoprion
arose some 270 MYA. Long includes the story of how a superb whorl was stolen
from a Russian museum, identified by an American fossil dealer when put up for
sale, and in a tale out of a spy novel was retrieved, clandestinely brought
back into Russia and handed over.
The larger marine reptiles of the Mesozoic were the next
direct challenge. Some were bigger than any shark, but the air-breathers couldn’t
invade the deeps. The first lamniform, of the group including the modern great
white, appeared in this era. The sharks even developed some very large species
and spun off the rays as a new type. When the mosasaurs vanished after the K-Pg
impact, the adaptive sharks wriggled through yet another extinction event and diversified
again, producing the wobbegongs and hammerheads. They also grew bigger,
culminating in “the Meg.” Otodus megalodon was the all-time shark king
from 23-3.6 MYA. (When offering a vignette of a Meg attack, Long commits what I assume is a wording error, where he credits early baleen whales with
echolocation), The world moves on, though, and the Meg was ill-adapted to a
cooling of the oceans and/or and the move
of the baleen whales to polar regions. It was in hunting Meg teeth as a boy
that Long first caught the paleontology bug, so I suppose you can thank the Meg
for this excellent book.
Long traces the rise of “the most sharky shark,” the great
white, and spends a chapter on what we do and don’t know about this awesome creature.
He rejects some of the upper claims (the famed Deep Blue may be closer to 17
feet than the claimed 21) but accepts an older 21-foot measurement. He explores
the diversity of the modern sharks, over 500 species (not counting skates and rays),
not overlooking the most numerous but often-ignored group, the deep-water
catsharks.
Long covers in the last chapters the clash – and cooperation
-of sharks and humans, the threats to sharks, and the many things we learn from
them. He concludes, “If we can save the oceans and save the sharks, we can save
the world.” He finishes off the book in exemplary fashion with detailed chapter
references, a list of scientific names, a glossary, and an index. The
accessibility of Long’s prose, his deep knowledge of, and love for, his topic,
and the well-chosen black and white photos and drawings illustrations combine to
make this the apex predator of modern shark books. Bravo!
Matt Bille is a writer, historian, and naturalist living in Colorado Springs. He can be reached at mattsciwriter@protonmail.com. Website: www.mattbilleauthor.com.
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