What You Can See on Feb. 14
Submitted by Ted Williams on Tue, 02/14/2006 - 08:54.
From Audubon’s Earth Almanac by Ted Williams and compiled in “Wild Moments,” edited by Connie Isbell, Illustrations by John Burgoyne, Storey Publishing, 174 pages. Frostbitten Pioneer They look like rats, only bigger, fatter, toothier, and slower. Opossums invaded North America from the south about the same time Caucasians invaded it from the east, and both invasions are still in progress. Because opossums evolved in a mild climate, the ones waddling through your headlight beams in the snowbelt from Yankeeland to Colorado are apt to have frost-pruned ears and tails. The loss of ear tissue only makes the beasts look uglier (if possible), but because they store a lot of fat in their tails, the abbreviation of those appendages may curtail their northward expansion. The opossum is the continent’s only marsupial. Females deliver bee-size young after only twelve and a half days of gestation. Newborns, essentially mobile embryos, haul themselves up into a kangaroo-style pouch, where they either die or find a nipple that expands in their mouths, buttoning them into place. In one study, a researcher could fit only 21 beans into the brainpan of an opossum skull but needed 150 to fill the brainpan of a raccoon. The opossum’s remarkable success proves what countless mid- and low-level business managers already know—that intelligence is no criterion for advancement. Strange Changes When the sun’s passage is still low and brief, and snow lies high like a shaken quilt, male eastern newts begin their pre-spawning transformation. If their pond has black ice or no ice, you may see them sashaying along the bottom most anywhere in the eastern half of our nation. Now tails grow flat and eel-like; vents swell; hind legs enlarge; and black, horny appendages form on inner thighs and tips of toes. The most useful words for anyone explaining this salamander’s life history are “but sometimes.” Usually, larvae transform into a subadult terrestrial stage called red eft, but sometimes they transform directly into the aquatic adult stage. Usually, adults have lungs, but sometimes (when they skip the eft stage) they retain their larval gills. Because newts exude a toxin, fish almost always shun them—in fact, in one experiment, trout died when newts were pushed down their gullets—but sometimes wild brook trout glut themselves on newts.