An Immense World: Reading Notes (2)

(Burrowing Owl Update Below)

I realize that if I kept these notes going at the same density as the first installment, I’d end up writing something like a Cliff’s notes of Ed Yong’s volume. The book is engaging for its richness of detail, most of it unexpected and thought-provoking. In what follows, I’m going to whiz through the content from higher up so that you can get an overview. You’re going to have to read it yourself to get face to face with the details.

The third chapter has the lovely title “Rurple, Grurple, Yurple — Color.” The point is that human eyes mostly have three-color vision, red, green, blue. By combining and opposing these, we can see literally millions of different colors. Most mammals, including dogs, can only see two colors, blue and yellow, as well as grey. Many other creatures are monochromatic, seeing only shades of black and white. But most birds, many insects, and a vast number of mammal species, not including most humans, can see ultraviolet (UV) light. Many plants, insects, and birds display ultraviolet patterns that they, but not we, can readily see. UV-colored feathers are how blue tits, barn swallows, mockingbirds, and the majority of other songbirds tell male from female, even though to us they look the same. We have no vocabulary for UV colors. That’s why Yong suggests “Rurple, Grurple, Yurple.” But a rare subset of humans, all female, are able to see UV, including a Brit who goes by the code name cDA29. Then there are mantis shrimp, with eyes on stalks that have a color vision system more complex than any other on earth. They are able to see not only vertically and horizontally polarized light but also circularly polarized light. They are the only animals that can see it. And they are also the only animals that generate it.

“The Unwanted Sense – Pain” takes us into a realm that Aristotle forgot and that has been in heated debate for centuries. Philosophers following Descartes long argued that animals have no emotions, including pain. That view is now in broad retreat. The pain of mammals is now widely conceded, if not respected. In the past two decades, research has demonstrated that fish feel pain. Octopuses, also. But crabs? The research is still out. Nematodes? Mosquitoes? Most insects don’t respond to injuries in a manner that indicates pain or suffering, but it’s impossible to know for certain.

Chapter 5: “So Cool.” Some ground squirrels can survive in near-freezing or even sub-freezing temperatures. The heartbeat of the thirteen-lined ground squirrel drops to a few beats per minute. They can stay in a near-frozen state for six months if necessary. They need that ability to survive the winter. A group of proteins called the TRP channel forms the temperature sensor set for most animals. They vary greatly depending on the animal’s needs. Each has its own “hot” and “cold” limit sensor. At the extremes are Saharan silver ants, active at 127°F, or snow flies, at 21°F, or ice worms. Their sensory systems are tuned to be comfortable in those ranges. Nearly all animals will navigate from areas where the temperature is not right for them to areas where it is. Fire-chasing Melanophila beetles swarm in huge numbers toward the heat (not the light) of forest fires. They can detect forest fires from 80 miles away. Once they arrive, they have an orgy of mating, and the females lay their eggs on charred bark, where the grubs thrive. Exquisitely sensitive infrared radiation detectors below their wings show them the way. Yong then describes other creatures that are talented heat-seekers, including threadworms, bedbugs, mosquitoes, tsetse flies, assassin bugs, vampire bats, ticks, and others. Among expert heat sensors is the rattlesnake, which probably forms something like a visual image of nearby warm bodies. Even in complete darkness, it can strike a rodent, and not just anywhere, but always in the head.

With Chapter 6, we go to “Contact and Flow.” Sea otters are special in a number of ways. Key among them is their paws. They are deeply connected to the otter brain, and very talented. They can, for example, discriminate between fine textures that challenge a human touch, and do so instantly without double-checking. This ability lets them palpate the sea floor even in murky waters and quickly come up with edibles. The star-nosed mole has eleven finger-like protuberances on its nose that help it find and devour tiny bits of food and give it a detailed picture of the tunnels where it spends its life. Many bird beaks have sensory organs that signal edible material, even out of the beak’s range. The manatee’s mouth is a touch and feel sensory organ. Many other animals sense their immediate surroundings without directly touching. Using whiskers, other hairs, and skin sensors they can sense air and water currents produced by other creatures, following tracks that are invisible to human senses. Yong takes a detailed look at the powers of harbor seals to detect the paths that fish leave in the water as they pass. Fish in turn pick up cues through sensors called the lateral line. Supersensitive to motion and pressure, they let the fish feel everything around them up to a body length or two. Fish in schools, even blind fish, keep oriented through these sensors. Alligators have skin sensors that can detect super tiny ripples on the water’s surface. Birds have tiny feathers that read the air while in flight. Bats have tiny hairs that do the same. The tiger wandering spider doesn’t spin a web. It waits on a leaf. Supersensitive hairs on its legs can detect the air currents of tiny approaching insects. Many other insects have their own versions of hairs that detect the tiniest of air currents. They are much more sensitive than any visual receptor. Much more sensitive than we.

Well, I’m afraid I’ve overburdened my readers’ patience again. I’ll return to this book in a concluding post tomorrow. Thank you for hanging in so far.

Burrowing Owl Update

Burrowing Owl (Athene cunicularia) Dec. 9 2022
Burrowing Owl (Athene cunicularia) Dec. 9 2022

Once again the Burrowing Owl switched perches. It sat in Perch B yesterday, where park visitors could easily see it. It moved to Perch A this morning. To see it, I had to cross the “art” fence and set up the telephoto rig on the Open Circle Viewpoint, a good 110 yards from the bird’s perch. While I was filming, the bird mostly stood quietly, looking left and right in a relaxed manner. Occasionally it alerted briefly, but shortly after got a bit drowsy. The highlight of my watching came when the bird, after alerting, relaxed and puffed itself up into a big round ball of feathers. Normally when the owl puffs up for a few moments, it’s to poop. I didn’t see that happening here. Instead, the bird seemed to be doing some kind of stretching exercise, extending all its body feathers as far as they could go. Perhaps this also serves a defensive function, making predators think that this is too big a prey to take on. Burrowing Owls normally puff themselves up to some extent. I’ve never seen one to this extreme. It was a sight worth remembering.

The owl wasn’t the only inhabitant of the rocky slope to the east of the Burrowing Owl Sanctuary. Down low near the water’s edge dwelt a pair of Western Gulls, a Willet, an American Coot, and what must be a Least Sandpiper. Seeing just one Least Sandpiper is like seeing just one ant. Something’s missing! Nevertheless, there it was.

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One thought on “An Immense World: Reading Notes (2)

  • December 9, 2022 at 11:04 pm
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    I wonder what determines which eyelid, lower or upper, does the closing and opening. Usually it seems to be the upper lid that performs the action. Occasionally, it’s the lower lid. In today’s video, it was a double-feature (see from 14 to 19 secs) –first the upper lid closed, that the lower lid was raised in concert with raising the upper lid so that the eye remained essentially closed, though now due to the lower lid covering the eye instead of the upper lid which initiated the closure.

    Is this choice of eyelid deployment intentional, or a more autonomic behavior?

    And why does the owl almost always close its eyes (upper lids go down) during the moment it turns its head/gaze from one direction to another? Is this an opportune moment to “blink” and clear/clean the surface of its eye, or is it a way to not become “dizzy” during those rapid head (visual field) movements, or …?

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