Science

June 30, 2016 7:52 AM

Sharks in utero

(possibly cartoon sharks? not sure, I am not a shark scientist)

posted by beerperson (21 comments total)

That's very cool!

I'm 100% sure my wife would take an ultrasound floating in the ocean at this point, if she were given the option.
posted by Bulgaroktonos at 8:32 AM on June 30, 2016

Big fan of the cartooning over the shark ultrasound (starts around 0:37)! Such a cool way to add visual clarity to real data for people who have never seen thirty sharks in utero before.
posted by little onion at 8:34 AM on June 30, 2016

"Thirty Sharks In Utero" is splendid.
posted by Bob Regular at 9:00 AM on June 30, 2016

Neat!

I didn't even know that sharks gave birth. I assumed that they were like other fish that lay eggs, and that only the placental mammals had solved the complex immunological problems of hosting another body inside your body. Do all sharks do this? Only some? Are there any other fish who do it?
posted by clawsoon at 9:00 AM on June 30, 2016

Indeed. Word up, all the cetaceans get down like this, clawsoon.
posted by Bob Regular at 9:02 AM on June 30, 2016

Shark reproduction is pretty varied, I believe, with some laying eggs and some giving birth to live young, and with some of the sharks that give birth having a system somewhat like a placenta and others having eggs that hatch internally and then develop further. These are tiger sharks which I believe are that last option.
posted by Bulgaroktonos at 9:08 AM on June 30, 2016 [1 favorite]

But the cetaceans are placental mammals, Bob Regular, so they don't count. :-) They descended from the same live-birth-giving animal that we did, not that long ago. They're close relatives to us. Sharks are on a faraway branch of the tree of animal life which, as far as I know, doesn't have any live birth in between us mammals and them.

Or does it? That's fascinating, Bulgaroktonos. I never knew there was so much reproductive variety in sharks! Does this mean that some sharks have sex, too?
posted by clawsoon at 9:16 AM on June 30, 2016 [1 favorite]

I believe they all do, but I'm not totally sure.* Male sharks have two appendages called claspers they use (one at a time) to impregnate female sharks.

*I am not a shark biologist, this is not shark family planning advice. I was just super into sharks as a kid.
posted by Bulgaroktonos at 9:23 AM on June 30, 2016 [5 favorites]

Shark family planning is a career path I now regret not looking into.
posted by mykescipark at 9:34 AM on June 30, 2016 [2 favorites]

Fish do usually lay eggs, but plenty of common species bear live young instead, including guppies.
posted by Spathe Cadet at 9:37 AM on June 30, 2016 [2 favorites]

Shark family planning is a career path I now regret not looking into.

You'd be trying to fit condoms on sharks, and Right to Shark protesters would be constantly circling your clinic...
posted by clawsoon at 9:40 AM on June 30, 2016 [2 favorites]

oh my god I want to have another kid now just so I can troll people by posting a still of the shark ultrasound to facebook
posted by prize bull octorok at 10:12 AM on June 30, 2016 [8 favorites]

Right to Shark protesters would be constantly circling your clinic...

Unsure but I think that's the sequel to Blake Lively's new movie.
posted by MCMikeNamara at 10:12 AM on June 30, 2016

Gotta admit- they really are packed in there like sardines!
posted by Bob Regular at 10:24 AM on June 30, 2016

...Except that sardines are generally tessellated.
posted by Bob Regular at 10:25 AM on June 30, 2016

Wow. Emily is full of a lot of fetal sharks, and they all have a lot of teeth. I'm glad human babies don't emerge full of erupted teeth, and in packs of 20-30.
posted by ChuraChura at 10:55 AM on June 30, 2016 [5 favorites]

I guess that's why sharks didn't also develop breastfeeding.

(Or did they? I'm fully ready to be blown away by more science facts today...)
posted by clawsoon at 10:59 AM on June 30, 2016

YESS. THE LITTLE TEETHS.
posted by sparklemotion at 11:17 AM on June 30, 2016 [1 favorite]

Some sharks use those little teeths to eat each other in utero.
posted by tavella at 1:46 PM on June 30, 2016 [5 favorites]

You can spot the lefties in the room by looking for the people who are kind of excited when they learn that fact.
posted by sparklemotion at 1:55 PM on June 30, 2016

"There was a bright light, and I was swimming, and there were these weird lumpy creatures. Not like us. They were breathing in the air and not in the water. And then I'm not sure what happened, I fell asleep. I think they drugged me and maybe probed me!"

"Whatever Emily, we're so tired of your alien abduction story."
posted by bunderful at 7:37 PM on June 30, 2016 [5 favorites]