Evolution of Live birth (Why do mammal not lay eggs?)

Mammals, like almost all other types of animal today, used to lay eggs, but then they adapted to give birth to live young. why did some mammals make this change and if it has been so beneficial why haven't more animals evolved to do it?

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[bulldog]

One of the things I find fascinating is how humans can find almost any baby mammal to be cute. I often wonder if this is a common trait across all mammals.

[mariastevens]

I love that you've been doing this for 4 years now and still use such a calming voice. Please keep doing so. It's so much easier to absorb, and to be honest, I doubt I'm the only one who plays your videos to unwind or fall asleep to.

[DavidMcGuizz]

Echidnas might be the most underrated animal in terms of cuteness. Look at all of them running around together. Amazing

[purplehairstreak]

Fascinating! I’m currently 6 months pregnant and it’s absolutely delightful to learn how live birth evolved, especially the way the placenta has replaced the yoke in mammals as source of nutrition.

[maemorri]

One thing I learned that surprised me is just how many non-mammals also give birth to live young. Familiar species such as great white sharks and reptiles like garter snakes have evolved to hatch eggs internally and the baby(ies) emerges from the mother fully formed. While this may be a superficial similarity, it shows how easily varying reproductive strategies may evolve in widely separated lineages.

[Stephen-jwci]

such an interesting subject. if you haven’t already i highly recommend the book “the rise and reign of the mammals” it just came out recently. starts with the first tetrapods to show mammalian traits and goes all the way to modern times

[carsonianthegreat]

3:54 that leaf in the lower right is a Tuliptree leaf—Liriodendron. Tuliptrees evolved about a hundred million years ago (back before the mass extinction that killed the dinosaurs). That means it actually lived along side the mammal group featured in the image! That’s some insane attention to detail!

[grayphoenix]

Can we just appreciate how cute & happy that animal looks in the thumbnail? Like, she be singing while singing, hey this is my baby, we went for a walk & I'm having the nicest day of my life

[EliKennedy]

I really appreciate content like this where the entire focus is the subject matter at hand. It’s a refreshing oasis in a world stuffed with gimmicks.

[RalfTenbrink]

Great video. All your videos are of extremely high quality. Great to see you subscriber numbers are much higher than the last time I checked. Keep up the good work.

[saxoman]

You just absolutely blew my mind! Completely rocked my world with this video! This has been one of those questions I've had forever, and you're the 1st to really cover it. And now, Among other things, I know that placental mammals aren't the only ones that have placentas?!?! Freaking lizards and snakes have them too!? Mind blown!

But now I can see a bit more clearly how a Complex placenta evolved (For it seemed like an impossible leap that went unexplained to me before).

And somehow the fact that monotremes have the small one too was also mind blowing!

This is why I subscribe to you! You cover the hard hitting stuff, thanks!

[tar-mairo]

Longtime subscriber, first time commenting. Congratulations on your 100th video and hopefully there are many more to come!

[FooRise]

These videos are so fascinating, i love it. Absolutely great work. Thanks a lot for uploading and for all the educational content.

[rdongart]

You seriously make some of the best animal/biology/nature videos I have seen on youtube. Not all this crazy voice over sell click bait stuff. Your videoes are just packed with interesting information from start to end covering a subject in an easy to listen to way with relevant visuals instead of the "10 (random) facts about..."-style. Pure quality!

[jurassic_hobbyonmyaltaccou]

This is one of the best paleo channels out there great content

[DM-qlps]

While Kayentatherium Has larger litters than any living mammal, there are 2 Modern species that sort of come close. The Tailless Tenrec with 32 and the Virginia Opossum with 22. Both of these animals descend from ancestors who had much smaller litters, evolving large litters to cope with high predator pressure.

[mauriciomunoz]

Phenomenal content as always. Keep up the great work and congratulations on your 100th episode!

[EarthenExplorer]

Dude i just love watching your vids while I chill out and eat a meal. Makes me feel like when i was a kid watching nature documentaries so long ago.

[torinn]

I just assumed it was just because of warm bloodedness allowing for longer gestation periods. learning about all the cold blooded animals that give live birth was very fascinating. I love this channel.

[IamNoOne-]

THIS IS A TOPIC THAT I ALWAYS WANTED TO KNOW MORE! THANKS MOTH LIGHT MEDIA!!!!🦔🥚