卵齒

卵齒，指卵生羊膜動物（如鳥類）在出卵殼前，上喙先端形成硬化的角質物。

卵生羊膜動物（如鳥類）在出卵殼前，上喙先端形成硬化的角質物.由於雛鳥在胚胎髮育中吸收了大量的鈣質，使卵殼薄而脆弱.雛鳥較容易用卵齒在氣室附近啄破卵殼，然後用喙逐漸擴大裂縫，用身體向上頂卵殼的鈍端，使卵殼破裂而出殼.一般雛鳥出殼後數小時卵齒即脫落，只有鴞等一些鳥類保留一周以上.相 關 詞 條:兩棲動物 |鱷蜥 |GOOGLE英文翻譯:oviparous amniotes (such as birds) in the out of egg shell prior to the formation of hardened horny beak tip material. nestling in the embryonic development due to absorption of a lot of calcium, so that egg-shell thin and fragile. Nestlings easier to use eggs teeth in the gas chamber near the pecking broken egg shells, then use the beak gradually expanding cracks in the body upward with the top of the blunt end of egg shells, so that rupture of the hatched egg shells. usually a few hours after the eggs hatched chicks tooth that is off, only the owl and some birds retain more than one week. Related term: Amphibians | Crocodile Lizard |