A nose balloon too far

This great dead beast greets me every morning — it’s a cast of a Triceratops skull mounted across the atrium from my lab. It’s impressively large.


One thing has always bugged me about it, though. See that tiny hole directly under the horns? That’s the eye socket. It has a beady-eyed look, like mere eyeballs were an afterthought to long pointy sharp horns.

But then you go forward from there, and what you see is this massive cavity where the nostrils would go. It’s freakin’ huge. You could fit both hands in there, and it goes all the way through the skull. I’m a moderately gracile human being with a skeleton that’s delicate and fragile compared to a dinosaur’s, and I don’t have a giant gap in my facial bones that you could punch through without smashing up a few bones.


What’s up with that, I’ve always wondered. There must have been some impressive fleshy tissue in there, associated with olfaction? Or thermoregulation? Or what? Someone really needs to get right on that time machine idea.

Darren Naish has a far out, speculative, wild hypothesis: those giant meat holes contained colorful inflatable nose balloons for sexual display, because dinosaurs were weird.

I don’t know. It kind of detracts from the majestic dignity of the animal to imagine it puffing out what would look like a gaudy snot bubble to appeal to a mate. What self-respecting beast would do that?


Next thing you know, these paleo guys will be dressing dinosaurs up in flamboyant plumage. No dignity left at all.


  1. davidnangle says

    If I’ve got an eye lined up with a big, pointy horn, and you’ve got a big, red balloon indicating the clearest path to your brain…

  2. says

    Do both genders have the gaps?

    As to the weirdness – totally. Everything we’ve learned about the deep past has shown that an awful lot of live has been a lot stranger – by our standards – than we ever gave it credit for.

  3. monad says

    I don’t know. Sure, it’s a nice speculation, and Naish makes it plain it’s not anything more than that. But I feel like “sexual display” is going from being something invoked in cases of adult sexual dimorphism to the default assumption for anything you can’t figure out, from crests to horns to feathers to enlarged nares.

    It’s hard to test for, but that doesn’t mean it should be the null hypothesis. In truth, that’s not even the only type of display out there – even taking nose balloons, why assume they wouldn’t they be for intimidating rivals in a social group or warning away predators? (I don’t think Naish actually says, but it’s assumed here).

  4. taraskan says

    Eh, I want to agree with monad. Whether people are talking paleontology or fictional alien biology or new species of marine life, ‘body part used in mating ritual’ tends to get thrown around a lot more than is credible just as a first-pass, sort of like technical assistance asking if your device is plugged in.

    But in this case, it seems plausible that that huge opening would be covered in some fashion, otherwise think of the parasites and insects that would fester inside it. And that is not an animal that can easily reach or clean a facial orifice. Hell, you could fit a family of marmots up there.

    It could also be these animals had to smell mates or tribes over 50+ km distances, if they were comparatively rare and spread out over the Laurasian plate.

  5. weatherwax says

    My first thought would have been muscles for some sort of prehensile trunk. But the shape of the hole would probably rule that in or out.

  6. handsomemrtoad says

    There are stranger ways of courting than by inflating nose-ballons. I myself seduced my very first girlfriend by reciting The Hunting of the Snark from memory. All of it. Reciting the poem took many times longer than losing the virginity.

    That’s a true story.