Animal RecordsWhat's Size Got to Do With It?
Amazing Numbers in Biology
Rainer Flindt. 2006. Springer-Verlag, Berlin. 295 pp., softbound. $29.95.
Why Size Matters: From Bacteria to Blue Whales
John Tyler Bonner. 2006. Princeton University Press, Princeton. 161 pp., hardbound. $16.95.
How big is it? How small is it? People are fascinated by the size of things. At the Zoo, the labels that identify animals invariably include their weight or length or both. And, in fact, knowing an animal's size tells us a lot.
You may not have heard of an animal called a bongo, but if I say one weighs between 500 and 900 pounds, you'll immediately know what it's not even if you have only passing familiarity with the animal kingdom. You can eliminate all invertebrates and all birds and amphibians. Adding that a bongo is about five feet tall omits reptiles and fish.
You can also easily eliminate almost all mammals, the vast majority of which—rodents, bats and the like—are small. Of the big ones, only a few exceed 500 pounds, and others are too big—rhinos and elephants, for instance. Now you're down to just a few possibilities: Only some whales, carnivores, and artiodactyls (even-toed ungulates) are this size. You might need a few more clues to figure out that a bongo is an artiodactyl (specifically, an African bovid), but in a multiple-choice test, a random guess would give you a one-in-three chance of getting the correct answer.
Knowing something about animal sizes may help you pass a pop quiz or win at Jeopardy. This knowledge also clearly has some intrinsic interest for most of us, and it's easy to find the size—weight, length, height, diameter, et cetera—of almost any species, as well as lists of the biggest, smallest, or tallest of whatever group you're interested in. But if you are curious about how much an elephant's heart weighs (about 43 pounds) or how long a sperm whale's intestines are (945 feet), or the diameter of a lion's eyeball (1.4 inches), Amazing Numbers in Biology is the book for you. It should certainly be on the shelves of parents with school-age kids.
German biologist Rainer Flindt has assembled an amazing—the title doesn't exaggerate—array of what scientists call "biological values" in four categories: zoology, microbiology, botany, and human biology, and not only values related to size. Flindt covers a huge number of such disparate and intriguing things as "daily urine volume in humans at different ages," "auditory acuity of selected animals," and "lifespan of leaves and needles of selected evergreen plants." If you're like me, you'll open this volume to look up, say, the pH values in the mid-intestine of a bedbug, and before you know it you'll be 20 pages on, checking out the blood pressure of a shark.
Amazing Numbers is even more interesting because Flindt puts so many values in a comparative perspective. For example, an elephant's huge heart forms only about four percent of its body weight, while a weasel's, at just 1/50 of an ounce, is nearly 17 percent of its weight, and a hummingbird's, which is slightly larger than the weasel's, is 24 percent of its weight.
Weirdly fascinating as it is, Amazing Numbers is pretty much raw data. Why Size Matters puts it all in perspective. In this small volume that you can read in an hour or two, John Tyler Bonner explores a big question: How does the size of an organism affect virtually everything else about it, from its ecology and evolution to its locomotion, life span, and the relative size of its heart and eyeballs?
Professor emeritus of ecology and evolutionary biology at Princeton, Bonner has been thinking about size and its implications for more than 60 years. Why Size Matters is his summation, a masterful and engaging work, elegant in its simplicity despite its subject's complexity. Bonner frames the book around five ways in which size rules. Strength, shape, complexity or division of labor, rates of processes such as longevity and speed, and abundance of organisms all vary with size, and they determine just about everything else, including most of Amazing Numbers' biological values.
If the handful of graphs and equations scare you, Bonner relieves the stress with a running discussion of how Jonathan Swift got the traits of Gulliver's Lilliputians and Brobdingnagians right or wrong. His examples of how "size rules life" are drawn from zoology, business, architecture, and transportation. And he has a way with metaphor. Because human sperm are so small, he writes, their movement is like that of a person "trying to swim in thick molasses in which one is not allowed to move one's arms or legs faster than the hands of a clock."
Try these two wildly different books on for size—I think you'll find they make a good fit.
—Susan Lumpkin
ZooGoer 3(1) 2007. Copyright 2006 Friends of the National Zoo. All rights reserved.
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