Marginalia

Of the many books read this winter, this one really blew my mind. Not just once, but over and over.

An Immense World
How Animal Senses Reveal the Hidden Realms Around Us
by Ed Yong

Yong is a gifted science writer. He has rare talent for finding extraordinary things about the natural world, and sharing them in layman’s terms. But he manages to do it without over simplifying or talking down to the reader. If you know something about the topics discussed, you won’t be offended; and if you know nothing at all, the path is made easy.

The whole book is a series of explorations of the five primary senses we know well. Not just as humans experience them (though there’s some startling insights here, too). Instead, he focuses on what is actually happening beyond the narrow ranges we can perceive – extra sensory perception. The range of light invisible to us, but normal to other creatures. Birds and insects that use UV light, snakes that see infrared. Whales and elephants that communicate with infrasound, below our hearing, and dolphin and bats and even their prey that use ultrasound. Smells, taste, touch, direction . . . even time.

Here are a few things I learned:

• The squeaks we hear from bats is nothing. The shrieking they actually make would be so loud, if we could hear it, that we could not stand to be outside with them flying overhead. In fact, the sounds they make are so loud that even they would be made permanently deaf by it. So they have evolved a special bone in their inner ear that opens and closes at the same frequency as their echolocating pulses. Weird enough, but this has to be timed so precisely that it closes just before they make the sound and has to reopen before the sound waves bounce back from the world outside, including their prey. So the timing accelerates as they approach a moth or an obstacle. Otherwise they miss, or crash.
• Some moths have evolved a way to make a jamming frequency, specifically to nullify the sound of pursuing bats. Like noise cancelling headphones.
• The sonar of Dolphin and Porpoises is so sensitive and accurate, they can detect the difference between otherwise identical brass and steel rings buried in the sand. If one object is just a millimeter out of square they can tell the difference from a perfect one. They can see through bodies of people and fish, like X-ray vision – determine fish species by the shape of their internal swim bladders, and whether a woman swimmer is pregnant or not.
• Whales communicate over thousands of miles of ocean, using channels in the seabed like a pipeline.
• Elephants communicate through the ground, listening with their feet.
• Birds have touch sensors on their bills, and can pick up the electromagnetic waves of worms, and the earth.
• Wasps can feel with their stingers. Which they use to probe out and sting specific nerve bundles inside cockroaches, their prey:
  • “This wasp—a beautiful inch-long creature with a metallic green body and orange thighs—is a parasite that raises its young on cockroaches. When a female finds a roach, she stings it twice—once in its midsection to temporarily paralyze its legs, and a second time in its brain. The second sting targets two specific clusters of neurons and delivers venom that nullifies the roach’s desire to move, turning it into a submissive zombie. In this state, the wasp can lead the roach to her lair by its antennae, like a human walking a dog.”

These astounding bits of information roll out chapter after chapter, and are just some of the many wonders found therein.

One surprise is that humans, while blind and deaf to many sensory inputs, we’re actually very, very good at a few of them. Our sense of touch in our fingers is so sensitive, we can detect the difference in surface textures when one is only one molecule thicker than another. That’s like if our fingertip was the size of the whole earth, we could feel the houses on its surface.

If you have any interest in science, or ever wander around wondering what you don’t see or hear or feel, like I do, I highly recommend treating yourself to a good read. You will realize that the world as we perceive it is very two dimensional compared to the one we walk around in.

Here’s a good lengthy interview with Ed Jong, where he discusses many of the things he discovered while compiling the book, and what lead him to write it.