Earth Almanac: July/August 2004

Swimming Ahead

After summer warms earth's temperate seas, look for a towering fin flopping back and forth in near-shore waters. It belongs not to a shark but to the ocean sunfish (Mola mola), earth's largest bony fish, which is taller than it is long and weighs as much as 5,000 pounds. Propelled by dorsal and anal fins, and steered by its nearly nonexistent tail, the ocean sunfish seems to be all head. If you're lucky enough to encounter one, it will most likely be basking, often lying on its side as if sick. If you approach quietly and slowly, you can sometimes reach down and stroke its rough hide, which may have seaweedlike parasites sprouting from it. Ocean sunfish appear to invite seabirds and fish such as wrasse to pick the prolific parasites from their gills, fins, and flanks, rolling over when they fancy that one side has been sufficiently cleaned. Ocean sunfish suck in food through their toothy beaks, spit it out, suck it in, spit it out, and so on, until the pieces are small enough to swallow. They have a varied diet that includes eelgrass, mollusks, jellyfish, salps, algae, plankton, and small fishes.

Armored Beast

Summer is mating season for the nine-banded armadillo, a bone-encased, largely insectivorous mammal that looks and behaves as if it had been invented by P.T. Barnum or Hugh Lofting. For example, with all its armor, the armadillo is heavier than water. So when confronted by a stream or a pond, it walks across the bottom, holding its breath for as long as six minutes; or, if the water body is large, it inflates its stomach and intestines, then paddles across. Moreover, a single embryo, which can remain dormant for 14 months, always produces four identical offspring. The first known report of an armadillo sighting in the United States was in Texas by John James Audubon and John Bachman in 1849. Since then, assisted by humans in states east of the Mississippi, the species has made its way to Oklahoma, Kansas, Nebraska, Colorado, Missouri, Arkansas, Mississippi, Louisiana, Alabama, South Carolina, Georgia, and Florida. Armadillos, also called "gravediggers," are skilled excavators, especially when they smell food, which, as it has frequently (if incorrectly) been reported, includes human remains.

Spooky Spiders

If you've spent much time around fresh water almost anywhere in the United States, but especially in the South and Northeast, you've probably encountered fishing spiders. They're the huge, hairy ones that wave at you from under docks and diving rafts and skitter across the surface, rowing (but only with the dimples their legs make in the surface tension). If there's a breeze, the larger species occasionally will sail by holding their two front legs aloft. Fishing spiders eat water-bound insects, tadpoles, and small fish; large fish eat them. Summer is the time to seek out fishing spiders and study their behavior. But be careful! These arachnids, which can have leg spans of three inches, are afflicted with peoplephobia. In fact, if you frighten them too badly, they may submerge for a half-hour, breathing air trapped between their hairs.

Wildflower Guide

If you can find your way to a compass plant, you can find your way with it. Now, in prairies and other dry habitats in the middle of our nation, this towering aster, which grows to between 4 and 10 feet, is heavy with yellow, saucer-size flower heads. To keep cool, the compass plant transpires water through its 12- to 18-inch-long leaves; to minimize exposure to sun and thereby conserve water, it orients the leaves in a north-south direction. Pioneers found their way by the compass plant. The resin makes fine chewing gum, and smoke from the burning roots wards off lightning—or so claimed the Pawnee and Ponca Indians.