Ask Lemmy
A Fediverse community for open-ended, thought provoking questions
Please don't post about US Politics.
Rules: (interactive)
1) Be nice and; have fun
Doxxing, trolling, sealioning, racism, and toxicity are not welcomed in AskLemmy. Remember what your mother said: if you can't say something nice, don't say anything at all. In addition, the site-wide Lemmy.world terms of service also apply here. Please familiarize yourself with them
2) All posts must end with a '?'
This is sort of like Jeopardy. Please phrase all post titles in the form of a proper question ending with ?
3) No spam
Please do not flood the community with nonsense. Actual suspected spammers will be banned on site. No astroturfing.
4) NSFW is okay, within reason
Just remember to tag posts with either a content warning or a [NSFW] tag. Overtly sexual posts are not allowed, please direct them to either [email protected] or [email protected].
NSFW comments should be restricted to posts tagged [NSFW].
5) This is not a support community.
It is not a place for 'how do I?', type questions.
If you have any questions regarding the site itself or would like to report a community, please direct them to Lemmy.world Support or email [email protected]. For other questions check our partnered communities list, or use the search function.
Reminder: The terms of service apply here too.
Partnered Communities:
Logo design credit goes to: tubbadu
view the rest of the comments
Elasmobranch reproduction and embryology. It's just a topic that has always been interesting. Sharks, rays, and skates are all rather closely related. But we have skates- which lay eggs (oviparity); rays- which give live birth, via internal egg incubation (ovoviviparity); and sharks- which, depending on the species, lay eggs, incubate the eggs, or experience a more "mammalian" pregnancy known as vivparity. And then, there is the intrauterine cannibalism that is known in the species Carcharias taurus, where the fetal sharks are still developing, the yolk sacs have been depleted, so the fetal sharks eat the others within the uterus, resulting in the birth of two offspring (sharks have two uteri, so one from each).
And then there is the parthenogenesis phenomenon, that we only know about because of captivity. Certain sharks- notably bamboo sharks- if absent of a mate, can trigger a response that causes ova to mature and develop into a clone of the mother. This is also known to happen in lizards.
And a large number of female elasmobranchs can also store the sperm of males after copulation to fertilize their eggs for years.
It's just a fascinating topic all around.