00:00 It was quite a long scene of Dreadnoughtus.
00:03 Here they are.
00:05 A fight scene.
00:06 It was a fight scene in this territorial battle
00:11 between males.
00:12 And I think this was actually kind of based on our science,
00:16 because what we found with the two Dreadnoughtus individuals
00:20 is that the much larger one, the 65-ton one, was osteologically--
00:26 that means its bones-- was osteologically quite young.
00:29 You might even think of it as a teenager who
00:31 was growing rapidly at the time of its death.
00:34 Whereas the one that we found that was 1/3 smaller
00:38 osteologically was much, much older.
00:41 And so where do you find this in animals today,
00:43 where you find older, smaller individuals and younger,
00:46 bigger individuals?
00:47 That's in species where you have sexual dimorphism, where
00:51 the two sexes are of different sizes.
00:55 And usually that happens where you have
00:56 male-dominated sexual selection, which
00:59 means that two alpha males are going
01:02 to compete with each other to control a territory
01:05 or a group of females.
01:06 There's also female-dominated sexual selection.
01:09 That's where you see the males showing off
01:11 with all kinds of colors and doing fancy tricks
01:14 and buying Corvettes and things like that.
01:17 And so with Dreadnoughtus, we have just a hint
01:21 that we have sexual dimorphism.
01:24 And then based on a hint that maybe it
01:28 was male-dominated sexual selection.
01:30 And that's what you are seeing here.
01:32 And then--
01:33 These air sacs, we've got to talk about these air sacs.
01:35 Yeah, let's talk about the air sacs.
01:36 What do you think about that?
01:38 Well, the air sacs are kind of hard to miss.
01:41 I have to tell you that there is zero evidence
01:43 that Dreadnoughtus had air sacs.
01:46 These are pneumatic goulard pouches
01:49 like a grouse would have today.
01:51 Is it impossible?
01:53 No, it's not impossible.
01:55 But we don't have any evidence that they--
01:58 we've had that.
01:58 Now, I was told by the consultant on the show
02:02 that they wanted to find a way to illustrate the fact
02:07 that extinct animals must have had amazing soft tissue
02:11 structures that will never be preserved in the fossil record,
02:14 which is certainly true.
02:15 If we only knew elephants from their skeletons,
02:18 I probably wouldn't really know what an elephant looked like.
02:22 So this is an example of a hypothetical feature
02:26 that maybe we're missing completely in the fossil record
02:29 that could have existed.
02:31 Did they specifically have this?
02:34 Probably not.
02:35 Is it impossible that they had this?
02:36 No, it's also not.
02:38 But we don't have any evidence of it.
02:40 What we do have, though, is we have their cervical vertebrae.
02:45 And the cervical vertebrae are very pneumatic,
02:48 meaning that they have a system of air tubes and air bladders
02:54 that invade the bone over the lifetime of the animal.
02:56 So the bone becomes more honeycombed with air over time,
03:00 making it very light but still retaining most of the strength.
03:03 Because if you have a 40-foot-long neck,
03:06 a 40-foot-long lever, you don't want
03:08 to put a lot of weight at the end of that lever.
03:10 So they have these very lightly built pneumatic necks, which
03:14 I guess gave them the idea, OK, there's air in the neck.
03:17 There's a lot of air in the neck.
03:19 Why not something like male grouses in the breeding season
03:23 that have these pneumatic coulard pouches that
03:25 pop out like that?
03:27 Thinking of a story of Droidnatus.
03:31 I know.
03:32 It's always interesting to draw inspiration
03:34 from modern creatures.
03:36 There he goes.
03:37 I guess we'll have to hold out for any more fossil or soft
03:41 tissue preservation.
03:43 Yeah.
03:43 There's certain things that we're just never going to know.
03:46 And we have to live with that disappointment.
03:50 But there are a lot of soft tissue features
03:52 that extinct creatures have that we're just never going to find.
03:56 We can make inferences about them.
03:57 Sometimes we can do that from molecular work
04:01 with modern creatures.
04:02 We can look at the DNA from groups of related creatures
04:06 and figure out where that trait must have started.
04:10 Occasionally, you get soft tissue structures preserved
04:15 if you have very clay deposits that can preserve
04:19 that kind of resolution.
04:21 But that's very rare.
04:21 And I don't see that scenario happening
04:23 for big things like sauropods.
04:24 That happens for little things like birds.
04:28 And then there's always the promise
04:30 of molecular paleontology where we routinely
04:34 recover blood vessels and blood cells and proteins
04:38 from dinosaurs and other extinct creatures.
04:41 A few DNA bases have been recovered.
04:43 Is it possible we'll have a genome
04:45 of a dinosaur, a non-avian dinosaur in the future?
04:50 No, it's a pretty high mountain to climb.
04:52 But I can't say that it's impossible.
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