Tyrannosaur's Stomach Contents Have Been Found | Hacker News Reader

Tyrannosaur's Stomach Contents Have Been Found

scientificamerican.com

73 pointsBrajeshwar41 comments

Interesting.

I hope we can clone and make dinosaurs and other extinct creatures again.

It would be fascinating to visit a park where we could see these creatures in as natural of a habitat as we can provide them today.

To each their own, I just wish my iphone 5 would still hold a decent battery charge

You get used to it. I browse less on mine because I can’t.

I sat for 10min and the battery went down 20%.

I kinda like it. Also the charger port is so fucked that it can only charge in a very specific incline. I hate that. From 2016, going strong otherwise. Might change that port tho.

Have you tried recycling the old battery and putting a new one in? The physics of commodity lithium ion batteries are immutable. /s

Didn't you see the movie?;)

It was quite spectacular. I hear they spared no expense.

Hollywood filmmakers always find a way.

There's a reason they keep reopening the park in the movies.

Make it happen.

The 521-year half life of DNA makes that pretty much impossible I’m afraid. Probably won’t be able to bring back anything more than a few hundred thousand years old if that.

See: <nature.com/articles/nature.2012.11555>

What if it was preserved in some amber?

Well in a sense dinosaurs still live to this day, as birds.

> Oviraptorosaur nests typically contained at least 30 or more eggs. With such large broods, “you could imagine, at certain times of year, depending upon the species and when their breeding season is, this would not be an uncommon prey for predators,” Zelenitsky says. That’s why she isn’t surprised to find remains of this species in this Gorgosaurus’ stomach, especially because she “can’t see the adults going after these tiny little chicken-sized or turkey-sized dinosaurs.”

I'm curious why they assume the adult tyrannosaurids wouldn't eat the oviraptorosaurs because that makes no sense to me. My cats will chase down and eat flies and mosquitos so is there some sort of size threshold for agility that the tyrannosaurids pass through that makes it impractical to hunt small prey? They are believed to be warm blooded so it's not like they could really ignore easy prey at that size.

Perhaps other big carnivorous dinosaurs might have eaten small prey when given the opportunity, but for adult tyrannosaurids this seems less likely.

The adult tyrannosaurids had arms that were far too short to be able to catch small prey with them.

The heads of the adult tyrannosaurids were very big, so they must have had a large moment of inertia that would have made difficult to rotate the heads fast enough to be able to catch small prey on the ground below them.

Perhaps the best chance for an adult tyrannosaurid to catch small prey would have been to stomp on it (like many prey birds, e.g. the secretary birds, do today). Only then it could have easily taken the dead body in the mouth.

This stomping behavior would be a more plausible means for tyrannosaurs to catch humans in a movie, instead of their typical depictions when they catch easily the humans only because those are frozen by fear instead of taking evasive actions. (The tyrannosaurs could certainly move their feet many times faster than their heavy heads located at the end of long necks.)

Your cat doesn't feed itself and is artificially selected to hunt for fun which skews this comparison a lot more than just the physical size.

Tigers eat grass and small animals like termites just like domesticated cats do so I don't think their diet has been selected for as much as you think. They more likely became popular as pets because of what they eat.

Avoid evolutionary arguments, they're "just so" explanations that can be twisted to fit any narrative.

I didn't say the diets were selected, just that a domestic cat can afford to be habitually inefficient in a way most wild animals can't and that we have selectively bred cats for some of this. Yes, big predators will opportunistically eat smaller prey, it doesn't affect the claim that a domesticated cat is a poor starting point for the comparison you were making.

> Tigers eat grass

Tigers, and housecats, don't have the digestive system to get sustenance from grass. A cat swallowing grass is kind of like a chicken swallowing gravel; it's not food.

If tigers could eat grass as opposed to just swallowing it, they would have no reason to hunt anything; they're more than capable of driving away most things that would compete for their grass.

Fun fact: Chickens actually need to swallow gravel in order to digest any food since they don't have teeth. They store gravel in their gizzard and when the gizzard moves, the food is ground with any grit material inside. Once ground to a paste it can _then_ pass through the digestive tract. So definitely a component of food for chickens, unlike grass for tigers.

That's like saying that chewing is a component of food for humans (and everything else).

Chewing is an important way to increase the amount of nutrition you get from a fixed amount of food. It isn't itself food.

>Tigers eat grass

Lol. Yeah, they eat grass and then vomit it out. Just like my cats do. Helps them relieve themselves of furballs.

(Cats are only partly domesticated and feral cats certainly manage to feed themselves.)

Yeah but I bet feral cats don't feed themselves on flies unless they have no other options. It's not efficient.

In case your interested in more light reading on this: https://www.newyorker.com/tech/annals-of-technology/are-cats...

> Cats have us do everything for them. We clean their litter, stroke them, admire them, but, unlike dogs, they do not have to constantly please and satisfy our needs.

It seems like cats may have actually domesticated humans.

It is probably better to have a less losing strategy to hunt smaller pray, while searching for bigger? The marginal effort to catch a mouse can't be that high while roaming around searching for bigger pray?

I think you are underestimating the difficulty of catching a mouse.

I have hunting dogs and they can spend several hours going after a mouse, and their success rate isn't very good.

Plus, large animals are poorly Suited to hunt much smaller animals. Speed, momentum, and anatomy are not in your favor. Imagine driving a semi truck and trying to run over a mouse

Ye maybe you are right. I would not even try to catch a mouse by hand myself. And I have no clue how a lion would compare to a house cat in hunting a mouse.

But your dogs, do they hunt with their feet? I don't think dogs use their claws like cats do, making it really hard to get to the mouse? Like, dogs can't do a slap like cats and humans can?

Yes, dogs incapacitated prey with their mouths, and use their paws less.

That said, I think the bigger differences tho are momentum, distance, and turn radius. A tyranasaures head is something like 10ft off the ground. By the time it winds up and reaches the ground, the mouse would be long gone.

There are great documentary videos of large cats chasing desert rabbits that show this really well. The cats are bigger and faster and stronger, but the rabbits can turn faster.

Pumas have been observed to catch mice.

I suspect there are two issues here put together in a possibly misleading way: 1) it is not surprising that the juvenile Gorgosaurus would have fed on the smaller animals, for fairly obvious reasons that have nothing to do with what the adults would have fed on; 2) the small animals would not be an adequate diet for adults.

If this is the case, then it seems odd for the latter to be used as a justification for the former, but when people are talking extemporaneously, it is not uncommon for them to jump from one topic to another without completing the former.

As an example of how larger predators often ignore small prey, consider how some hummingbird species seek out nesting sites close to those of hawks:

https://www.audubon.org/news/why-hawk-hummingbirds-best-frie...

Presumably adults normally went after prey large enough to satisfy their appetite, but push come to shove would have eaten smaller prey too, just as a modern lion prefers a decent meal like a zebra but will still eat anything from a rodent on up if it's hungry or an easy chance presents itself.

The "can't see adults going after these" seems a sloppy throw-away comment, not based on any evidence, and ignoring common sense!

Large carnivores are kind of the pricey boondoggles of evolution. They work, they are successful, but they're balanced on a knifes edge. Every step a large carnivore takes consumes vastly more energy than it would cost a smaller animal. It is all too possible for such a creature to expend more energy pursuing small prey than it would get back. That is why lions don't hunt small game- they'll scavenge small game by driving off smaller carnivores from their kills, and they certainly won't turn down eggs if they find any, but they will not pursue prey beneath a certain size. Imagine trying to catch a rat with your hands- exhausting work, and the rat isn't much food

I was watching "Our Planet 2" on Netflix last night and they showed a pack of lions taking down a huge male cape buffalo. 3 min from start to meal time. Very efficient!

https://1ft.io/proxy?q=https%3A%2F%2Fwww.scientificamerican....

surprised there are no remains of a fur bikini...

What are the two front legs for?

If the ratios in the popular diagrams of a T-rex are correct, they cannot make a T-Rex eat anything. And if the creature walks the way they are drawn, they effectively cannot be used to hunt and grab things either.

It must be a crawler, instead of a creature that stands up and walks upright. The head on the T-Rex is too heavy and large in proportion to the body for it to be walking upright for too long. It must be weighed down. The front two legs are for lifting the body in the center off the ground. And the back/bottom legs make it good walking forward rapidly.

Unpopular opinion: It is an oversized iguana-like reptile. A heavy head, with small front legs and oversized large back legs.

The front apendages are far too small for that to make any sense. Just compare iguana front legs with T-rex arms, proportional to their body size. And that's ignoring square-cube law scaling difficulties that would make it even worse. Those things would snap like twigs trying to hold up that body.

Evolution - T.Rex with it's upright stance evolved out of earlier animals that walked on four legs. The small size of the arms of most (but not all) species in this family of animals tells you that the arms were not normally used.

Some snakes (also having evolved from animals with legs) still have vestigial legs - all but disappeared since they too serve no purpose.

There has got to be some comparison to ostriches, giant moas and Phorusracids, where the pectoral appendages are absent or vestigial. They're all theropods as well.

iguanas have quite large front legs (but smaller) compared with their back ones - a bit like humans and many other animals

Same thing your appendix is for.

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