Exploring Unique Creatures of the Deep and the Dark! A guest post by Lindsey Leigh

In my books, I love to focus on unusual animals. In my first book, The Deep! Wild Life at the Ocean’s Darkest Depths, I focused on the wonderful weirdos that inhabit the deep sea, and in my newest book, The Dark! Wild Life in the Mysterious World of Caves, we explore the strange creatures that live in the isolated reaches of the cave. If you’re as passionate as me when it comes to odd animals, you’re in for a treat when it comes to cave creatures. There are olms, which are long, eyeless cave salamanders that can live for up to a hundred years, oilbirds which are one of the few cave-dwelling birds that can echolocate like a bat, and mysterious white leeches that live in freezing cold water at the bottom of a cave, just to name a few.

Cave animals that live full time in the cave must be specially adapted to live in a place that has no sunlight and often very little food. These special adaptations include slow movement to conserve energy, a loss of eyes as there is no need for them in the dark cave, and since vision is often reduced the animals in the cave have longer limbs and rely on their sense of touch to get around.

Cave animals are organized into three different groups according to how much time they spend in the cave. They’re organized into The Three T’s: troglobites, troglophiles, and trogloxenes. Troglobites are permanent cave residents that are specially adapted to living there and wouldn’t be able to survive outside of the cave. Troglophiles are part-time cave residents that are well adapted to the cave and prefer to live there, but they can also leave to find food if needed. And trogloxenes are cave visitors that pop in and out and only live in the cave at certain times.

As I wrote The Dark!, I noticed many similarities between the deep sea and the cave ecosystem. Deep sea animals also have a lack of pigment, loss of eyes, and reliance on other senses because they live in a world of darkness as well.

In both the cave and the deep sea, the sun isn’t present to create food so animals must rely on other methods to get a meal. Animals in the deep sea eat marine snow, which are bits of dead animals and poop that float from upper ocean layers down to the deep. In the cave, some animals rely on bats and crickets to leave their guano (another word for poop) behind for them to eat. I learned that both environments revolve around poop!

Animals in both environments also survive thanks to microscopic bacteria. In the deep sea, communities of life spring up around boiling hydrothermal vents because of the presence of bacteria there. Bacteria in the cave don’t need sunlight to grow and instead they feed on the minerals that are found in caves. In Movile Cave in Romania, bacteria created an entire ecosystem! The cave was isolated from the world for millions of years until it was accidently discovered by miners in 1986. They were surprised to discover a cave full of bacteria growing there, and an assortment of other animals like cave leeches, water scorpions, and woodlice. The bacteria in the cave eat the methane and sulfur found in the cave and the animals in turn eat the bacteria.

Many of the animals that live in the cave are what some would consider a little freaky looking! My personal philosophy is that there are plenty of cuddly and charismatic animals that are universally loved, and people wouldn’t think twice about supporting their conservation efforts. But there are plenty of lesser known, perhaps less visually gifted animals that deserve our attention and support as well. As such, I always like to give special attention to the creepy crawlies, and I tried in this book to make them funny and appealing. For example, a creature like the whip spider can look so frightening to humans on the surface, but I wanted to highlight the fact that whip spider mothers will take care of their young and even caress them with her feelers!

In regards to my creative process for these books, I start by reading books and scientific papers on the subject, then I try to break down the ideas into simple concepts and images that will be understandable for all age groups. I also find humor is a great way to communicate ideas for young readers and I hope that the jokes in the book make the facts fun and memorable. For example, as I was reading the paper on how whip spiders that live in caves are much less aggressive than those that live outside of caves, I imagined cave whip spiders acting like proper gentlemen with top hats and being excessively polite when they bumped into each other, which made it into the finished book!

Even though many of these cave ecosystems have survived for many years, they are very sensitive and vulnerable to different threats from the outside world. Caves are so delicate that too many tourists visiting can alter the sensitive humidity level of the cave and also disturb animals that live there. Pollution (like sewage, accidental spills, and industrial chemicals) also can easily seep through into the cave and pollute aquifer water, which is bad news for animals and people that rely on that important water source.

Sure, cave animals are a little strange, but like all animals on this planet, they’re worth admiring and protecting. Caves are one of the most fragile ecosystems on earth and they hold so many treasures of scientific discovery and mysteries to unravel. These places have survived for millions of years and hopefully they’ll survive for millions more. I hope this book sheds some light on the strange and wonderful animals you might find in the darkest reaches of caves!

Meet the author

Lindsey Leigh grew up in the Washington, D.C. area, fascinated by the Smithsonian museums and the Baltimore Aquarium. Her passion for communicating scientific ideas eventually led her to join the Guild of Natural Scientific Illustrators. She has since completed a Scientific Illustration internship with the Smithsonian National Museum of Natural History and has created educational comics for the Georgia Department of Natural Resources, Georgia Tech, and the magazine BBC Focus. She is the author of The Deep! (Penguin Workshop).

Instagram: @linseedling

X: @linseedling

About The Dark!: Wild Life in the Mysterious World of Caves

Crawl into the deepest corners of caves across the world and learn about the wonderfully weird creatures that live their lives in the dark!

Did you know that some creatures that live in the dark have adapted to have no eyes? Or that some dark dwellers have extra long antennae so they can feel their way around their homes? Have you ever seen a troglobite? There many different types of troglobites including the fearless waterfall-climbing cave fish, the mutant Mexican tetra, and the mystifying olm.

Author and illustrator Lindsey Leigh introduces young readers to some of the weirdest and creepiest critters that thrive in the darkest corners of our planet in her uniquely funny and graphic style. This fact-filled book reveals the different ways that creatures of the dark have adapted to thrive in their environments, including slow movement and loss of pigment in their bodies to blend in with their surroundings. Readers will get to know aquatic cave leeches, tailless whip scorpions, cave beetles, the devil’s hole pupfish, worms, salamanders, and all kinds of bats.

ISBN-13: 9780593662595
Publisher: Penguin Young Readers Group
Publication date: 07/09/2024
Age Range: 8 – 12 Years

Filed under: Guest Post