Some other evolutionary whodunits from the new world:

Why did pronghorn antelopes become the second fastest running animals in the world?

Why do honey locust trees have thorns all over their trunks?

That was a pretty solid one.
The new guy has a good presentation style.

Love the content, hate the hipster presenting it. Could barely get through it, despite the killer story.

I felt the same way at first, but he's kinda growing on me. (quick google search says his name is Michael Aranda)

Scishow being under the same umbrella as the Vlogbrothers, one inevitably ends up comparing him to John and Hank Green. And, well, he doesn't.

BUT, as awesome as those guys are, it took some time for them to develop their "instant gravitas" ability, and they only have so much time to devote to Vlogbrothers and associated stuff. So, I'm kinda willing to give this guy the benefit of the doubt and think he can develop into another very good presenter.

Maybe.

Hey, kid! What'd ya do, jump ship?

Did a quick search on your first one because stuff like this interests me.

The prevailing opinion seems to be the most intuitive; the Americas also had a variety of Pleistocene cats/cheetahs (explains the speed) and dogs/hyenas (explains the seemingly uncharacteristic endurance as compared to their Old World "counterparts") which evolved alongside the nigh-extinct family ( Antilocapridae) of which pronghorns are the last living
members.

The second one, I don't know, because the plant got bored one day (as they are wont to do) and decided to spice things up?

Why am I not surprised that a GROUND sloth went extinct

The story I have read is that honey locusts have thorns because North American elephants (mammoths, mastodons) were once tempted to push them over.

Agreed. I scrolled it so I didn't have to see the video and just listened to the audio and read the subtitles. If it's not an irritating presenter then it's a video full of hyper-rebus over-edited visuals. Or sometimes a mixture of both.

Badly titled.
It should be ...the delicious avocado is artificially selected deliciousness just like tomatoes.