January 30, 2023 15:19
vast world
Ed Young
Random House, page 449
You’re at a soirée, drink in hand on the host’s balcony, watching bats fly through the twilight. Fellow guests try to talk you down by mentioning that bats use echolocation, a form of sonar, to navigate and catch flying insects.
You may wonder why they are telling you things that everyone knows. But if they recently read “An Immense World,” a book on animal senses by Pulitzer Prize-winning science journalist Ed Yong, they might have something new to tell you.
For example, bats are the loudest animals alive. There is also a siren-like scream at 138 decibels. Luckily, it’s too loud for you and your new friend to hear.
In fact, Yong writes: They do so by contracting their middle ear muscles in time with their calls. This causes desensitization of hearing during yelling, [less loud] echo. And they send out pulses of sound at “vocal muscles that can contract up to 200 times per second – the fastest speed of any mammalian muscle.”
Wait, don’t leave the balcony yet! “They also space their calls so that each one is made only after the echo from the previous one has returned. The air between the large brown bat and its target fills with calls or echoes. You can never be satisfied with both.”
That’s what a bat can do alone. But in a group flight where millions of members may be chatting, how do you not confuse each other?
Dubbed the “cocktail party nightmare,” this conundrum is still unsolved. However, some theories are explained.
The title “Big World” is apt. Yong shows that seemingly familiar senses like sight can extend beyond the human experience. Most people can see millions of colors, but birds can see hundreds of millions. This includes unimaginably exotic blends of every color you’ve ever seen in a Crayola box, as well as UV shades you’ve never seen before.
The consequences of having or not having certain sensations are often surprising. South American squirrel monkey populations contain both ‘trichromatic’ with strong color vision and ‘dichromatic’ with weak color vision, each with a survival advantage. “Certainly trichromatic eyes are better at spotting brightly colored fruit, but dichromatic eyes are better at spotting insects disguised as leaves and sticks.”
Yong also writes about less familiar sensations, such as vibration and flow detection, which some researchers describe as “touch at a distance.” Seals can use their whiskers to track ‘hydrodynamic wakes’, invisible trails of turbulence left by passing fish. One researcher said a harbor seal could track a herring nearly two feet away from a soccer field. A seal zigzags through the water like a hare zigzags through the forest, like a hare hound zigzags through the water through fish.
The facts presented in this review are merely a taste of what Yong reveals about the sensory world of birds and mammals. He also introduces heat-seeking snakes, magnetically sensitive sea turtles, electroreceptive platypuses, and mosquitoes that taste skin with their feet the moment they land.
“Infinite World” will fill your head with so many facts to share that you too might be someone’s cocktail party nightmare, or a science lover’s dream date.
