National Geographic : 1954 Sep
the wood powder gradually colored the shells a dull brown; a short time after the eggs were laid they were practically invisible. The soft, pliable, but tough shell changed in outline and contour as development of the embryo pro gressed, showing bulges and hollows to fit the small new body taking shape within. Three of the eggs were opened by ants and their con tents eaten. The remaining 12 grew normally. About five weeks after the mother had left them, one of the larger eggs began to heave and wobble. A tiny slit appeared in one end of the shell, and a pair of round bright eyes peered out for the first time. The whole head soon poked through the crevice. A little later an 8-inch snakelet perched atop the heap of eggs containing his laggard brothers and sisters. He did not have long to wait for them. In a few hours the hollow log swarmed with baby snakes. By the third day, only a heap of empty torn shells was left to mark the site of the nest. Snakelets Shed Skin to Grow On the tip of each little snake's nose was a small, hard, pimplelike structure called the egg tooth, which had been sharp enough to make the first incision in the shell above the young snake's head. It would dis appear soon after hatching. The baby snakes did not immedi ately make their way outside. Still attached to each was the remainder of a yolk sac which had provided nourishment during the prehatching period; the youngsters had no need to hurry in seeking their first meal. While resting near the scene of their hatching and still feeding upon the egg yolk, the little snakes began to grow ever so slightly. The scaly skin of snakes cannot stretch to ac commodate growth, as does that of mammals and birds. Nature there fore has made provision for growth by the frequent shedding of the entire outer skin, leaving beneath it a new skin a little larger than the old one. 339 Jack Dermid Rough Bark Provides a "Foothold" for a Bold Prowler Snakes crawl by moving overlapping crosswise belly scales, or plates. Few species can climb trees as readily as this North Carolina Corn Snake (pages 351, 353), which selected a rough barked loblolly pine for its demonstration. Handsome colors, hardiness, and docile nature make this yard-long constrictor a favorite of amateur naturalists.