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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