How Do Scientists Know If A Dinosaur Is Male or Female?

How do paleontologists know the sex of a dinosaur fossil? The quick answer is that they don’t! However, some fancy techniques have been concocted in the last 30 or so years that have helped provide more solid answers on if a given dinosaur or prehistoric animal is a male or female. This also drastically changes depending on what group of animals we are talking about. It’s much easier to determine the sex of more recent extinct mammals than ancient dinosaurs because in many cases there are living cousins and descendants of these ancient mammals with us today for comparison. Sometimes sexual dimorphism - or the differences between the sexes - is very obvious and pronounced. Male gorillas are far larger and more robust than females - but humans have the least amount of sexual dimorphism among the apes. Many reptiles with us today run the gamut of sexual dimorphism, from the same giant male and tiny female dynamic of primates seen in tortoises, all the way to species that have no sexual dimorphism because they are composed entirely of one asexually reproducing sex.
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✅ RESEARCH ✅
Saitta ET (2015) Evidence for Sexual Dimorphism in the Plated Dinosaur Stegosaurus mjosi (Ornithischia, Stegosauria) from the Morrison Formation (Upper Jurassic) of Western USA. PLoS ONE10(4): e0123503. doi:10.1371/journal. pone.0123503
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[@prehistorica-official-2024]

Fun Fact: A 2013 study found that female Apatosaurus and Diplodocus had interconnected caudal vertebrae that allowed them to keep their tails elevated to aid in copulation. Based on the discovery of this fusion in 50% of Apatosaurus and Diplodocus skeletons and 25% of Camarasaurus skeletons, it indicated that this is a sexually dimorphic trait. Btw, this is my first comment on the channel.

[@Kargoneth]

Interesting. A raised tail would seem to preclude the male from mounting the female. Welcome to the channel.

[@rosalinadeanda-zd6nn]

Amazing, finding the gender of Sauropod Dinosaurs is amazing since sexual dimorphism is still being studied in Sauropod Dinosaurs.

[@samalfriiaskham3671]

Puts a whole nother meaning on "EDGE science" 💀

[@ogrejd]

Huh. Never noticed before that stegosaurs had armored throats. That must've been useful.

[@i.m.evilhomer5084]

In the words of every comedian out there, "Very carefully.".

[@jdtrash6470]

Instructions unclear, I'm now paying child support to a stegosaurus

[@rileyernst9086]

Considering how common allosaurus specimens are I would definitely have to agree with the statement that they had strong natural pressure to defend themselves!

[@JAGzilla-ur3lh]

Oh, cool, I was about to Google this question. For a friend. I have a weirdo friend who asks questions like this. Hypothetical questions. I don't care about the answer, but he was wondering, so I'm humoring him, is all.

[@WesPresto]

The thumbnail. 💀

[@patreekotime4578]

How to Sex a Stegasaur got me running.

[@samuelcampo3611]

Now that is what i call Clickbait alright.

[@troyallen8223]

First thing you do is get some candles some wine and some videos. Stay away from the hardcore stuff.

[@rosalinadeanda-zd6nn]

The thumbnail has nothing wrong, the word sex can also been gender. Its not clikbait. Either way this is Paleontology so get used to it.

[@evandergozali7419]

@@rosalinadeanda-zd6nn bro blew the whole joke

[@patreekotime4578]

I kept waiting for discussion about the stegosaur neck beard. It was highlighted as a potential sexed trait several times.

[@Kargoneth]

Dewlap?

[@patreekotime4578]

@@Kargoneth It is something that fossilized. But it is not mentioned in articles I read about soft tissue preservation in this species.

[@Kargoneth]

@@patreekotime4578 Oh. Interesting.

[@buckledben]

Fun fact: almost all monogamous birds have no sexual dimorphism. While polygamous birds most often then not have some form of sexual dimorphism.

[@beastmaster0934]

Other than physical size.

[@lordcooler8160]

Albatrosses and Swans (monogamous birds) are dimorphic in size and the Andean Condor (also monagomous) has size dimorphism as well the presence of a fleshy crest in the male

[@patreekotime4578]

A weird thing about birds is that most of the sexual dimorphism we see is not stuff that fossilizes. So there may very well be a Cardinal dinosaur with bright red plumage on the males and drab brown on the females and we may never know.

[@Kurenai1819]

Very interesting topic! It never crossed my mind as someone who is not paleontologist.

[@Kyoryu_The_One]

Thumbnail threw me off a bit

[@Kurotitan7125]

This is reminding me of two things: Barbara the T Rex, who was a confirmed female because she was gravid And the discovery that Big Al, the famous Allosaurus jimmadensi, was actually a gravid female when she died

[@pRODIGAL_sKEPTIC]

I'm just happy the idea is still alive of some hadrosaur or something having a giant turkey snood that just didn't fossilize 😂

[@rosalinadeanda-zd6nn]

Amazing, I find it so amazing and intresting that we can find ways to identify the gender of Prehistoric animals or at least get close. I love Paleontology.

[@RocketHarry865]

I wonder if the horns spacing layout of triceratops can determine the gender assuming that males mostly used their horns in competitive fights against other males. The males would have horns that tend to go outwards to the side slightly allowing them to lock horns with less risk of causing significant damage to their faces, while females may have horns that are more straight on.

[@EDGEscience]

Nope. Horns are different from individual to individual (with general similarities overall, hence the two knowm species).

[@Tyrant_Boi]

I edge to edge to science

[@nazzkid23]

cool!

[@jasepoag8930]

VERY carefully.

[@rextheoldsoul7558]

I know I’m getting to the comments rather late with this one, but I wanted to at least defend the Judith River Dinosaur Institute. I’ve worked with them a handful of times over the years. The curator of the Institute when asked about where the fossils would be going, assured us all that they would be going to a museum. He did not disclose which one for I’m sure he has some sort of contract with them. I can also assure you that the work they’re done is incredibly professional, even though most of it is done by volunteers. All of it is being overseen by the head, curator himself and his interns. I do not believe you were trying to slander the Judith River Dinosaur Institute. I just didn’t want anybody to get the wrong impression about them.

[@TheDinohunterify]

Next you're going to tell us how to edge one

[@Idate._intrepidus7]

I am guessing either by size like male is larger and female smaller Larger dorsal plates in male than female Or male more colorful than females

[@birbdad1842]

Could very well be the opposite.

[@sonkeschluter3654]

Animals as different as anglerfish and hyeanas would like to protest the bigger=male and small=female thing

[@steventhompson9672]

In most birds of prey, females average larger than males. Granted, stegosaurs were herbivores and non-flying. But the tendency in living dinosaurs goes towards females being larger.

[@SarastistheSerpent]

In reptiles it is not uncommon for female to be larger than males. Snakes for example are essentially universally dimorphic, with females being large and robust and males being smaller and lither. Turtles and tortoises also generally show female-dominant size dimorphism. Many birds as well, in particular birds of prey.

[@rosalinadeanda-zd6nn]

This can vary, since reptiles can be large due to individual variation. In reptiles, females can be bigger, but assuming that males are large is not wrong since Dinosaur have large amounts of diversity. In terms of color, this is much more skeptical, since age and individual variation can determine the colors' organism posses. When it comes to anatomical features like plates, males might have had much broader plates since larger spaces can contain more coloration or can simply appear bigger. But yet again, tall plates can make the Stegosaurus look larger. Those are just my personal thoughts and opinions.

[@carlos-ze3yo]

How to what?

[@tomholroyd7519]

1:00 idk I would say the sexual dimorphism between male and female humans is large, because we notice certain things, you know? Things that would not be preserved in the fossil record. Large fat things. Fleshy wattles ... no ... the other fleshy protuberances

[@EDGEscience]

Whatever your own bias is, the fact is that we are far less dimorphic than other mammals.

[@Ragetiger1]

However you failed to notice the pelvic girdle. That would remain in the fossil record easily.

[@EDGEscience]

You failed to realize that the pelvic girdle actually varies enough between individuals that it's difficult to sex a human skeleton from pelvi alone.

[@Carlos-bz5oo]

Many features we consider dimorphic in humans actually are the result of culture. Women can be hairy and men can have breasts.

[@34r343]

​​@@EDGEsciencebro in our anthropology class it was actually pretty hard to tell some times with the girtle so all of us used the robustness of the features on the skull like jaw and forehead pretty cool class tho

[@alwillcox]

Instructions unclear My stegosaur is now pregnant

[@gojira5157]

You might wanna change that thumbnail

[@EDGEscience]

Why

[@34r343]

It's a pair of stegosaurus what's wrong with it

[@patreekotime4578]

Got you clicking too fast??

[@34r343]

@@patreekotime4578 it's a picture of a stegasour I clicked cuz the title said how to tell it's sex?

[@patreekotime4578]

@@34r343 People are freaking out over the wording. It's hilarious but accurate.

[@xerasferalos9784]

you would require some protection

[@brianedwards7142]

Just get consent first.

[@user-pv3xc7hj5b]

А вы не пробовали заглянуть им под юбку ?

[@user-pv3xc7hj5b]

10:54 я тоже хочу такую кровать

[@AndrewDavis-sj6mb]

Prehistoric Gender 🤔 😮

[@vladline1882]

Oh.. no... Humans isn't different in dimorphism? Lol

[@EDGEscience]

We absolutely are, just not as much as all other apes.

[@tyrannotherium7873]

There is a big difference in sexual dimorphism with humans we have a bigger pelvis and longer hands and etc.

[@birbdad1842]

Oh yeah, such BIG differences. Really you should think about what you're saying before you say it.

[@EDGEscience]

This is an older idea of sexual dimorphism. There may be some minor sexual dimorphism with these traits, but there are also plenty of males and females with bigger or narrower hips. It's why pelvises are no longer used to sex a skeleton in archaeological contexts.

[@maddeeps5520]

​@@birbdad1842 We can accurately identify a 10000 year old skeleton of a human as being male or female I'd say that's pretty sexually dimorphic bro

[@rappsface]

​@maddeeps5520 actually, we can't, scientists have gotten it wrong several times. There's a channel I follow who helped get dna testing for an unidentified Jane doe known as preble penny, his skeleton was mistakenly identified as female and they only realised he was male after dna testing. This happens a lot!

[@An-kw3ec]

@maddeeps5520 Not really, it's always an approximation if the person's sex isn't confirmed by historical accounts, There are cases in which the sex of the person was wrongly classified because the burial rituals, clothing, skeleton, etc. did not match with each other. The same applies to race.

[@Masbax]

Clickbait

[@patreekotime4578]

Is it clickbait if its literally the proper way to say it AND the topic of the video?

[@34r343]

@@patreekotime4578 are some ppl this retarded 💀