The Greenland shark is the oldest vertebrate on the planet, capable of living hundreds of years in cold waters thousands of feet deep.
It is also uniquely smelly. Its body is designed to have the same salt concentration as the ocean -- such that it neither loses nor gains water through osmosis -- so it has to have a high concentration of the waste product known as urea.
That makes its meat toxic to humans when it's fresh, but it can be safely consumed if it's buried for several months to ferment and then hung to dry.
Some consider the resulting meat -- known as Hákarl by Greenlanders -- a delicacy.
"Apparently it tastes like a very ripe cheese, left for a week in high summer in a teenage boy's car," writes Katherine Rundell in "Vanishing Treasures: A Bestiary of Extraordinary Endangered Creatures."
In the delightful new book, Rundell spotlights 20 creatures in as many essays, writing of their strange habits and design, like a sort of literary David Attenborough.
She explains that wombats are much faster than they appear.
"Despite the fact that they do not look streamlined, a wombat can run up to 25 miles an hour, and maintain that speed for 90 seconds," she writes.
By comparison, Usain Bolt has reached speeds as fast as 27.8 miles per hour but only maintained it for less than two seconds.
In another essay, we learn that giraffe sex is typically a man-to-man affair, with some researchers finding that as much as 94% of giraffe intercourse is homosexual.
And, the lanky creatures' long necks exact a toll.
When giraffes put their heads down to drink water, blood rushes to their heads and their jugular veins close off to block blood to their brains so that they don't faint when they lift their heads back up.
"It is a dizzying things, being a giraffe," Rundell writes. "Even when water is plentiful, they drink only every few days."
Swift birds are like no other flying creature, eating and sleeping while in the air.
They're able to do the latter thanks to "unihemispheric sleep," allowing them to shut off one half of their brain at a time while the other half remains awake and keeps them aloft.
"The bird wakes in exactly the same place where it fell asleep; or, it migrating, on the precise course it set itself," Rundell writes.
In a single year, a swift flies roughly 124,000 miles -- the equivalent of five trips around the Earth.
The highest officially recorded speed for swift is 70 miles per hour, but more casual reports have clocked the birds at 105 miles per hour.
This is Rundell's second book to come out in the US this year.
The 37-year-old author's children's fantasy novel, "Impossible Creatures" was released in September and currently tops the New York Times bestseller list for middle-grade books.
It has drawn breathless comparisons to J.R.R. Tolkien and J.K. Rowling.
When it was released in the UK last year, it was heralded as the best book -- for any age -- of the year.
"Vanishing Treasures" is filled not just with intriguing facts but also beautiful and witty turns of phrases.
Pangolins, Rundell writes, have "scales [that] are the same shade grey-green as the sea in winter and the face of an unusually polite academic"
Wolves are the rare animal that communicates information using facial expressions, which Rundell quips, can be roughly translated as "ears flat back and close to the head: the tail between the legs: 'Don Corleone, I am honored and grateful that you have invited me to your home on the wedding day of your daughter. And may their first child be a masculine child.'"
The book doesn't just cover animals' behavior in nature, it also touches on strange interactions between wild animals and humans.
A chapter on raccoons covers Rebecca, an adorable mask-faced creature that was gifted to President Calvin Coolidge in 1926 to be cooked for Thanksgiving.
Instead, the First Family kept the raccoon as a pet and dressed her as was only fitting.
"Clad in her finery, she roamed the White House, unscrewing light bulbs and upending houseplants from their pots," Rundell writes, going on to note that she was exiled from her fancy digs for a time after biting Coolidge.
A more grim example in the essay on elephants relays how, in 1870 when the Prussians laid siege to Paris and blocked food supplies to the city, two of the zoo's elephants were slaughtered and their meat sold to the rich.
Nearly all of the creatures in the book are, or were at some point, endangered, and Rundell made a plea for readers to appreciate and protect the Earth.
"We have lost more than half of all wild things that lived. We are Noah's ark in reverse: it is as if we are raging through the bowels of the boat, setting fire to the stables, poisoning the water," she writes. "The time to fight, with all our ingenuity and tenacity, and love and fury, is now."