| 翻訳と辞書 |
snake
Snakes are elongated, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads with their highly mobile jaws. To accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and most have only one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca.
Living snakes are found on every continent except Antarctica, and on most smaller land masses — exceptions include some large islands, such as Ireland and New Zealand, and many small islands of the Atlantic and central Pacific. Additionally, sea snakes are widespread throughout the Indian and Pacific Oceans. More than 20 families are currently recognized, comprising about 500 genera and about 3,400 species.〔(snake species list ) at the (Reptile Database ). Accessed 22 May 2012.〕 They range in size from the tiny, 10 cm-long thread snake to the reticulated python of up to in length. The fossil species ''Titanoboa cerrejonensis'' was long.〔 Snakes are thought to have evolved from either burrowing or aquatic lizards, perhaps during the Jurassic period, with the earliest known fossils dating to between 143 and 167 Ma ago.〔〕 The diversity of modern snakes appeared during the Paleocene period (''c'' 66 to 56 Ma ago). The oldest preserved descriptions of snakes can be found in the Brooklyn Papyrus.
Most species are nonvenomous and those that have venom use it primarily to kill and subdue prey rather than for self-defense. Some possess venom potent enough to cause painful injury or death to humans. Nonvenomous snakes either swallow prey alive or kill by constriction.
==Etymology==
The English word ''snake'' comes from Old English ''snaca'', itself from Proto-Germanic ''
*snak-an-'' (cf. Germanic ''Schnake'' "ring snake", Swedish ''snok'' "grass snake"), from Proto-Indo-European root ''
*(s)nēg-o-'' "to crawl", "to creep", which also gave ''sneak'' as well as Sanskrit ''nāgá'' "snake".〔Proto-IE:
*(s)nēg-o-, Meaning: snake, Old Indian: nāgá- m. "snake", Germanic:
*snēk-a- m.,
*snak-an- m.,
*snak-ō f.;
*snak-a- vb., Russ. meaning: жаба (змея), References: WP (Vergleichendes Wörterbuch der indogermanischen Sprachen) II 697 f.〕 The word ousted ''adder'', as ''adder'' went on to narrow in meaning, though in Old English ''næddre'' was the general word for snake.〔''Online Etymology Dictionary'', s.v. "(snake )", retrieved on 22 September 2009.〕 The other term, ''serpent'', is from French, ultimately from Indo-European ''
*serp-'' (to creep),〔(【引用サイトリンク】 title=Definition of serpent )〕 which also gave Ancient Greek ''hérpō'' (ἕρπω) "I crawl".
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「snake」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|