y****5
发帖数: 131 | 1 "鲨鱼也是这样" is not true.
From wikipedia:
Sharks display three ways to bear their young, varying by species:
Oviparity: Some sharks lay eggs. In most of these species, the developing
embryo is protected by an egg case with the consistency of leather.
Sometimes these cases are corkscrewed into crevices for protection. The
mermaid's purse, which can wash up on shore, is an empty egg case. Oviparous
sharks include the horn shark, catshark, Port Jackson shark, and swellshark
.[23]
Viviparity: These sha |
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m******h
发帖数: 5753 | 2 那你解释一下什么是 Viviparity 吧
Oviparous
swellshark
, |
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H********g
发帖数: 43926 | 3 The female usually attaches the egg-case to a substrate, inserts it into a
suitably protective crevice, or carries it about until just before the eggs
hatch. Some species, however, are ovoviviparous, keeping the eggs inside
their bodies, with or without an egg-case, until they hatch. At least one
genus, Diploptera is fully viviparous.[15] |
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x****6
发帖数: 4339 | 4 难道没听过viviparity,蝰蛇等几种蛇是直接活生小蛇的。 |
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