Egg Tooth

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egg tooth

[′eg ‚tüth]
(vertebrate zoology)
A toothlike prominence on the tip of the beak of a bird embryo and the tip of the nose of an oviparous reptile, which is used to break the eggshell.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Egg Tooth


a hard sharp horny nodule in the embryos of certain reptiles (turtles, crocodiles, tuatara) and birds that develops temporarily on the upper jaw or on the tip of the upper part of the bill, respectively. The egg tooth serves to break through the shell. Immediately after the egg hatches, the egg tooth falls off. In some lizards and snakes the egg tooth is the anterior tooth of the premaxillary bone.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Ten days after the egg is laid, the young echidna uses die egg tooth on its snout to break through the egg.
After incubating for 60 to 80 days, hatchlings use a specialized egg tooth on their beaks (which falls off several days later) to slice their way out of the shell.
If you see a hatchling, look for a small white egg tooth on the on the tip of its snout.