How Reptiles ‘Reinvented Sex’ | Evolution | BBC Earth Science

[00:00:00]So, how do you impress a female?

[00:00:04]Probably not the best person to answer that. Been struggling all of my life, but I reckon this guy's in with a chance.

[00:00:10]What a magnificent animal. So handsome, honestly.

[00:00:17]This is a nyala, southern African antelope, and this is a mature male, and he is very, very impressive, certainly from that female's point of view.

[00:00:31]Okay, he doesn't have a sports car.

[00:00:33]Doesn't [music] need it. He's got those beautiful curled yellow-tipped horns.

[00:00:38]Doesn't live in a mansion. Doesn't need that, either. He's got those broad, powerful flanks.

[00:00:46]And what's [music] more, it's not just those characteristics, it's the fact that he's lived long enough to be able [music] to grow them. I mean, imagine if this guy had been born short-sighted or with a limp, he would [music] never have survived.

[00:00:59]>> When it comes to reproduction, it tends to be the biggest, hairiest males that succeed.

[00:01:08]Their genes get passed down, making future generations even bigger and hairier than the last.

[00:01:17]Which is how you end up with exaggerated physical traits like this.

[00:01:24]>> But let's be very clear here. These physical characteristics are not necessarily directly related to survival. What they're about is finding a mate, attracting that mate, and then successfully reproducing.

[00:01:40]Evolution is not always about survival of the fittest. It's critically about getting your genes into the next generation.

[00:01:51]And that was as profoundly important to the dinosaurs as it is to these nyala.

[00:01:58]Scientists suspect [music] that some dinosaurs did what many animals still do today.

[00:02:10]They show off.

[00:02:12]It starts with head-bobbing, followed by twirls.

[00:02:21]But to [music] really impress her, he has one final trick.

[00:02:34]It's irresistible. [music] His offspring will inherit [music] his attractive fuzz and go on to have fuzzy offspring of their own, becoming part of an extraordinary evolutionary transformation.

[00:02:59]Over time, fuzzy strands get longer and wider and split into multiple filaments, making an even bigger surface [music] area for display.

[00:03:18]Until [music] eventually, after tens of millions of years and countless generations, those fuzzy strands are so exaggerated, they've become something new.

[00:03:35]>> [music] >> Feathers.