These 5 Prehistoric Mammals Were Pretty Monstrous | TNTM

You may think bunnies, piglets, and even furry squirrels are cute and cuddly -- but it turns out that their prehistoric ancestors and relatives were quite the opposite.

In fact, these ancient mammals were extreme for their size, their ferocity, and even their locomotion. Here is just a sampling of the now-extinct mammals who once roamed the Earth. HuffPost Science's Jacqueline Howard reports.

HuffPost Science invites you to going the discussion with top scientists covering the latest news in spaceflight, brain/body research, evolution, and the influence of science on culture.

[Packless]

~2:35 looks like that nut-chasing guy from the Ice-Age-movies ;-)

[MaureenLycaon]

Just for the record: *Cronopio* wasn't really a squirrel or even vaguely related to them. It was a dryolestid, a critter even farther distant from most other mammals than platypuses and echidnas are.

[evilmatt]

Paraceratherium, the largest land mammal ever to walk the earth. 

[MrAntihumanism]

I like how this thing dipped in popularity once Cara Santa Maria left.

[vguyver]

I'm very disappointed here with this vid. Lack of information and details. Feels less "nerdy", and more "casual science for dummies". 

[cynnx]

very awesome and quick informative video but I just want to say that the music-choice and audio levels might need a little fine tuning. 

[CheshireCesare]

Deinotherium was my favorite prehistoric beast next to the smilodon, as far as mammals go. Sure, the first one probably wasn't as scary or dangerous as some of the critters on this list, but even as a kid never ceased to be fascinated by their unusually placed tusks

[DarDarBinks]

THERE IS NO SUCH THING AS A SABER-TOOTHED TIGER! The correct term is "saber-toothed CAT"!

[Mbrace]

One of my favorite prehistoric mammals ambulocetus.

[devalphamon]

The family of animals to ever roam the planet

[matthewbright]

I've always wanted a cute little venomous mammal pet.

[nukinneovenators]

When horses were the size of cats and we were squirrels

[uncleanunicorn]

The early cenozoic; when the rodents had horns, birds ate horses, and the whales walked.

[Dmdm_dm]

Hot lady talking about prehistoric mammals= awesome

[uncleanunicorn]

Aww... you didn't mention andrewsarchus, a predatory mesonychid living in proto Asia between 40 - 30 mya, and a land walking cousin of the whale family. 

[HoveringAboveMyself]

What bear-dog is referred in this video? they lasted for 30 million years and the largest of them lived 15 million years ago, it didn't look like a cross of a bear and a bulldog, it looked more like a big cat with a somewhat bear-like head.

[Cursedpug]

Is te dire wolf a real thing just asking

[Zamolxes]

Really, no sabertooth ? Disappointing.

[imarealpenguin]

Well, I was kinda hoping to see a bird no not the petstore bird. A ostrich's ansetor

[anjumkhan]

yup hyenadon and smilodon should have been there