Frog - Frog

Japanese: カエル(蛙) - カエル

A general term for the order Anura in the class Amphibians. The head and body are continuous. The limbs, especially the hind limbs, are well developed, and they have excellent jumping ability on land and swimming ability in water. The larvae are tadpoles with well-developed tails, but these disappear after metamorphosis. The skin is rich in secretory glands and is always moist. Many species store water in their cloaca. Breathing is done through the lungs and skin, but in the larvae, breathing is done through the gills. Many species have a vocal sac, and males sing particularly loudly during the breeding season. They are oviparous, and most undergo external fertilization. They lay eggs in still water, but some build egg masses on land or on tree branches and lay them in them. Their egg-laying habits are extremely variable, with some attaching them to their bodies or protecting them in their vocal sacs. Some species have poison glands in their skin. The ancestral form is thought to be Myobatrachus, which branched off from the labyrinthodont amphibians that flourished in the Triassic Period, and had a frog-like head and a long tail. There are 2,600 extant species in 22 families, with about 33 known in Japan.

Source : Heibonsha Encyclopedia About MyPedia Information

Japanese:

両生綱無尾目の総称。頭部と胴部が連続している。四肢，特に後肢が発達し，陸上での跳躍力，水中での遊泳力がすぐれる。幼生はオタマジャクシで，発達した尾をもつが，変態後は消失する。皮膚は分泌腺に富み，常に湿っている。排出腔に水をたくわえるものが多い。呼吸は肺と皮膚とで行われるが，幼生では鰓(えら)による。多くの種には鳴嚢(めいのう)があり，繁殖期の雄は特に盛んに鳴く。卵生で，大半は体外受精を行う。静水中に産卵するが，陸上や樹林の枝に卵塊を作って，その中に産卵するものもある。また体に着けたり，鳴嚢内に保護したり，産卵習性はきわめて変化に富む。皮膚に毒腺をもつものもある。祖先型は三畳紀に栄えた両生類の迷歯類から分岐したミオバトラクスなどと考えられ，カエルのような頭と長い尾をもっていた。現生種は22科2600種，日本で約33種が知られる。

出典　株式会社平凡社百科事典マイペディアについて　情報

<<: Frog - Batrachoi (English spelling)

>>: Return point