Alice Sheppard: This is a foolish basic question but am I right in understanding that sharks are technically fish rather than mammals, but they give birth rather than lay eggs? I’ve been meaning to look it up for years. Yes, everyone reading this may point and laugh now.

The shark doctor is in! Ask me anything. Have questions about sharks? Marine biology? Ocean conservation? Me? Anything at all? Ask me anything! Ask away, my flight is in two hours and I’m bored. Tag friends who might have questions, and please share! 🧪🦑🌎

This is a foolish basic question but am I right in understanding that sharks are technically fish rather than mammals, but they give birth rather than lay eggs? I’ve been meaning to look it up for years. Yes, everyone reading this may point and laugh now.

To everyone answering this: thanks, David has quote skeeted this (is that the correct phrase here? I've been away) so he has answered.

Well, yes but also "fish" isn't a clade so nothing is technically a fish. Kind of like "tree"

Mammals are defined by their mamaries, not by giving live birth! Although most mammals do have a placenta, which is their defining feature. Lots of animals give live birth: lizards, snakes, even frogs if you stretch the definition a bit.

My understanding is that delivery methods vary from shark specie to specie. Some lay eggs, some have live birth, some lay eggs into a special chamber where the eggs hatch and are later released into the water (sort of like certain male seahorses holding the brood for a bit).

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