Fossils Finally Prove Tyrannosaurs Were Hunters

[Earnest Cavalli]

Fossils Finally Prove Tyrannosaurs Were Hunters

Though T. Rex may have scavenged food periodically, science now has proof that the quintessential terrifying dinosaur was a predatory hunter.

In 1874 geologist Arthur Lakes uncovered what would later be known as the first Tyrannosaurus teeth documented by the then-fledgling field of archaeology. Those wicked, curved chompers would form most of the early basis for what science (and to a greater degree, pop culture) imagined the Tyrannosaurus may have looked like in life. How could a creature with teeth like that do anything but chase down prey, tear its throat out, then feast on the bloody remains?

As sensible an assumption as this seemed, science spent the next century unable to find any fossilized proof of a T. Rex hunting anything. There was certainly evidence that the dinosaurs were scavengers, and periodically we'd find bones with tooth marks and tracks that suggest predation, but nothing that could conclusively demonstrate that the beast was a hunter. Until now.

Researchers digging in South Dakota recently unearthed the spine of a 4-ton, fossilized hadrosaurus in which was embedded a kitchen knife-sized Tyrannosaurus tooth. According to the scientists, the spine exhibited enough evidence of post-attrack bone growth to support an assumption that the hadrosaurus was injured, survived, then lived for quite some time after the tooth was embedded.

"The animal was attacked, survived and escaped," says University of Kansas Biodiversity Institute paleontologist David Burnham. "Until we found this specimen, people could say that T. rex was a scavenger; here is evidence it attacked living things."

In conclusion, three cheers for science! Normally it does nothing but disprove our awesome childhood fantasies, but in this case we learn that T. rex was exactly as terrifying a killer as we all assumed while walking out of Jurassic Park screenings circa 1994. Propers to science - and primeval reality, I guess - for not stepping on our collective childhood whimsy.

Source: Wall Street Journal [http://online.wsj.com/article/SB10001424127887323664204578607911233796672.html]
(Propers to Dinosaur Comics [http://www.qwantz.com/index.php] for the image.)

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[Daystar Clarion]

A pretty shit hunter if the Hadro survived.

Good for you T-rex, I never doubted the saviours of our world.

 

[Godhead]

Fuck yeah, science is once again here to prove what everybody already assumed was true once again.

 

[roushutsu]

Was there any doubt that the T-Rex was a hunter? Next you're going to tell me the Pterosaur didn't fly, but was simply falling with style.

 

[Quaxar]

Well technically it could still have been a battle for something completely unrelated like territory. And it doesn't disprove them being scavengers, it's merely a single instance of a T. rex biting another living dino. That'd be like taking <url=http://moray.ml.duke.edu/projects/hippos/Newsletter/news68.html>this article and saying hippos exclusively ate meat.

 

[Angelous Wang]

I would imagine T-Rexs were like lions in a way.

Lions are fully capable of hunting and killing their own food, but allot of the time they will just follow hyenas or other weaker predators around let them do the killing and then steal it. Because it easier to intimidate than hunt.

 

[BloodSquirrel]

I always thought the "Trex is a scavenger" was a pretty dumb theory.

Looking at the modern world, how many scavengers do we have that are the size of apex predators? And I mean actual scavengers- predators as a rule won't pass up a free meal if they find one. Scavengers tend not to be huge and built like a brick shithouse. The territory to support something like a Trex scavenging would be too large, and it would be too easily outmaneuvered by smaller, faster scavengers. Scavengers tend to be things like vultures or insects, not bears or tigers.

 

[CriticalMiss]

Maybe the T-Rex and the Hadrosaur were just experimenting with their sexuality, it got a bit rough and they decided to part ways and see other people? What say you Science!

 

[Random berk]

Was there any doubt that the T-Rex was a hunter? Next you're going to tell me the Pterosaur didn't fly, but was simply falling with style.

I always thought the "Trex is a scavenger" was a pretty dumb theory.

Looking at the modern world, how many scavengers do we have that are the size of apex predators? And I mean actual scavengers- predators as a rule won't pass up a free meal if they find one. Scavengers tend not to be huge and built like a brick shithouse. The territory to support something like a Trex scavenging would be too large, and it would be too easily outmaneuvered by smaller, faster scavengers. Scavengers tend to be things like vultures or insects, not bears or tigers.

An interesting point to note is that primary hunters like lions or dogs not necessarily the most efficient at eating. Once they kill their prey they eat just the meat, and often leave a lot of that behind. On the other hand, hyenas have good strong jaws specifically used for the purpose of devouring the tougher, less accessible parts of the carcass. They have a bite strong enough to chew through rhino bone and don't leave much of a kill behind. Guess what else had an extremely strong bite that would be well suited to tackling the tougher remains of a dead animal? Tyrannosaurus.

Another thing is, there's a fair bit of doubt that Tyrannosaurus could run very fast. It wasn't the best balanced animal, and it was damned heavy. If a Tyrannosaurus ran at the kind of speed portrayed in Jurassic Park and it fell, it could potentially damage itself very badly. Not a very good trait in an animal that had to chase down live prey.

Also, while a scavenger might not come across conveniently pre-killed animals as often as living ones, it would expend far, far less energy in scaring off any smaller predators from a kill than it would making one itself.

EDIT: Although reading the abstract of a related ecological paper, they say that based on ecological models, smaller scavengers tend to have a much better chance of finding and stripping a carcass before something the size of Tyrannosaurus does. Tyrannosaurus could cover the range, but as you say, @Bloodsquirrel, a larger number of smaller scavengers would get there first. That's much more compelling evidence than one injured Hadrosaur.

 

[Thunderous Cacophony]

They should have asked me; I've got a fossil [http://www.imdb.com/title/tt0107290/] somewhere in the basement that proves Tyrannosaurs were hunters.

 

[J Tyran]

I wonder if/when they will be able to answer if it was either an ambush predator (like a crocodile) or whether it hunted and chased down its prey.

 

[BloodSquirrel]

An interesting point to note is that primary hunters like lions or dogs not necessarily the most efficient at eating. Once they kill their prey they eat just the meat, and often leave a lot of that behind. On the other hand, hyenas have good strong jaws specifically used for the purpose of devouring the tougher, less accessible parts of the carcass. They have a bite strong enough to chew through rhino bone and don't leave much of a kill behind. Guess what else had an extremely strong bite that would be well suited to tackling the tougher remains of a dead animal? Tyrannosaurus.

Hyenas are predatory. Lions actually steal their kills all the time.

Another thing is, there's a fair bit of doubt that Tyrannosaurus could run very fast. It wasn't the best balanced animal, and it was damned heavy. If a Tyrannosaurus ran at the kind of speed portrayed in Jurassic Park and it fell, it could potentially damage itself very badly. Not a very good trait in an animal that had to chase down live prey.

There's a lot of doubt about that doubt. You could say the same thing about an elephant, and they've got a pretty nasty charge.

Also, the Trex being unable to move fast is another one of those things that doesn't make much sense in a scavenger. Scavengers have to cover a lot of territory in order to survive. It needs to get to a carcass before other scavengers eat it. "Big and slow" just aren't common properties among scavengers. It seems far more likely to me that the Trex was built for taking down other dinosaurs that weren't very fast either.

Also, while a scavenger might not come across conveniently pre-killed animals as often as living ones, it would expend far, far less energy in scaring off any smaller predators from a kill than it would making one itself.

Depends on how long it has to search for that kill. And how much smaller those other predators really are. If the Trex would have trouble taking down the prey, then it would probably have even more trouble taking down what killed it. You're ultimately much more likely to see a lion stealing from hyenas than you are vultures stealing from wolves.

 

[Random berk]

An interesting point to note is that primary hunters like lions or dogs not necessarily the most efficient at eating. Once they kill their prey they eat just the meat, and often leave a lot of that behind. On the other hand, hyenas have good strong jaws specifically used for the purpose of devouring the tougher, less accessible parts of the carcass. They have a bite strong enough to chew through rhino bone and don't leave much of a kill behind. Guess what else had an extremely strong bite that would be well suited to tackling the tougher remains of a dead animal? Tyrannosaurus.

Hyenas are predatory. Lions actually steal their kills all the time.

Got nothing to say on that one, my knowledge on hyenas isn't up to the minute.

Another thing is, there's a fair bit of doubt that Tyrannosaurus could run very fast. It wasn't the best balanced animal, and it was damned heavy. If a Tyrannosaurus ran at the kind of speed portrayed in Jurassic Park and it fell, it could potentially damage itself very badly. Not a very good trait in an animal that had to chase down live prey.

There's a lot of doubt about that doubt. You could say the same thing about an elephant, and they've got a pretty nasty charge.

Also, the Trex being unable to move fast is another one of those things that doesn't make much sense in a scavenger. Scavengers have to cover a lot of territory in order to survive. It needs to get to a carcass before other scavengers eat it. "Big and slow" just aren't common properties among scavengers. It seems far more likely to me that the Trex was built for taking down other dinosaurs that weren't very fast either.

An elephant is fast, sure, but fast enough to chase down animals whose only defence is speed?

It makes perfect sense as a scavenger. There's a huge difference between an animal being able to maintain a sprinting speed for an extended chase and travelling for very long distances. Tyrannosaurus might cover a huge distance while patrolling its territory, but that in no way makes it the fastest thing in its ecosystem.

Also, while a scavenger might not come across conveniently pre-killed animals as often as living ones, it would expend far, far less energy in scaring off any smaller predators from a kill than it would making one itself.

Depends on how long it has to search for that kill. And how much smaller those other predators really are. If the Trex would have trouble taking down the prey, then it would probably have even more trouble taking down what killed it. You're ultimately much more likely to see a lion stealing from hyenas than you are vultures stealing from wolves.

[/quote]

I never said anything about taking down other predators, just driving them off. A pack of smaller animals or even a single large predator might take down a prey animal, but if something bigger and more aggressive comes looking to steal its kill. it isn't going to fight to the death to defend it. The Tyrannosaurus only has to put up a show of force and it is going to be able to steal that kill.

Don't get me wrong, the new evidence for T-Rex being a hunter at least some of the time is compelling. These are points where I see that scavenging could also have been a big part of its lifestyle. Also, this one Hadrosaur that they found? That proves nothing on its own. Just that one Rex tried- and failed- to kill one Hadrosaur at some point.

 

[BloodSquirrel]

An elephant is fast, sure, but fast enough to chase down animals whose only defence is speed?

An African Bush Elephant can run at about 25 mph.

It's not going to run down a gazelle, but they'd be able to run down a hippo, which is probably closer to what a Trex would be hunting. And this is an animal which has no real evolutionary need for speed (an elephant neither hunts nor has any natural predators).

It makes perfect sense as a scavenger. There's a huge difference between an animal being able to maintain a sprinting speed for an extended chase and travelling for very long distances. Tyrannosaurus might cover a huge distance while patrolling its territory, but that in no way makes it the fastest thing in its ecosystem.

There's some difference, but not an excessive amount when it comes to basic build. You've got some species that specialize in sprinting, like the cheetah, but they aren't built that much differently than something like a wolf, which is a champion long-distance runner. Efficiency in energy usage in movement is good for both speed and long-distance movement.

The real difference is going to be in things like musculature and metabolism.

I never said anything about taking down other predators, just driving them off. A pack of smaller animals or even a single large predator might take down a prey animal, but if something bigger and more aggressive comes looking to steal its kill. it isn't going to fight to the death to defend it. The Tyrannosaurus only has to put up a show of force and it is going to be able to steal that kill.

The problem with being that much larger and more powerful than whatever made the kill is that it's going to limit how large what they killed was. A bear wouldn't survive scavenging kills that a housecat made, and if it tried it against a pack of wolves it's going to wind up with a fight on its hands.

Don't get me wrong, the new evidence for T-Rex being a hunter at least some of the time is compelling. These are points where I see that scavenging could also have been a big part of its lifestyle. Also, this one Hadrosaur that they found? That proves nothing on its own. Just that one Rex tried- and failed- to kill one Hadrosaur at some point.

As I've said, pretty much every predator will scavenge if the opportunity presents itself. The problems is that if you're basing your arguments off of "It couldn't hunt", then "It couldn't hunt, but it hunted sometimes and mostly scavenged" doesn't follow. If it hunted at all, then there were clearly problems with your "It couldn't hunt" arguments.

 

[Pedro The Hutt]

One instance isn't necessary conclusive proof. While it makes it plausible, I still tilt towards scavenger myself.

 

[Miss G.]

It makes perfect sense as a scavenger. There's a huge difference between an animal being able to maintain a sprinting speed for an extended chase and travelling for very long distances. Tyrannosaurus might cover a huge distance while patrolling its territory, but that in no way makes it the fastest thing in its ecosystem.

The lion and the grizzly make sense as perfect scavengers as well but no one disputes their apex predator status. They both aren't the fastest things in their ecosystem, both can run at speeds of at least 45 mph but can't maintain it for as long as their prey can and walk miles to cover their territories, both hunt, both scavenge when they want to save energy because they have the muscle and size to scare off smaller predators, and both like T-Rex have the sense of smell to lead them to carcasses though fresh would normally be their first choice.

Being a predator inherently means you have to exhibit and apply more creativity and problem solving to getting food than a herbivore needs to outsmart and hunt a plant. A predator that is slow needs only to find slower or less intelligent prey. Using modern contemporaries it might've:
-hunted similarly to a komodo dragon, also big and not fast, by biting and infecting its prey (the valleys in its teeth more than likely carried accumulated bacteria from scavenged meals) then simply following at its own pace to where the prey dies.
-ambush hunted like lions, slower than smaller cats with the trade-off of more power, teamwork, and the ability to scare others off of kills when convenient. I recall that they discovered T-rex might not have been solitary like we once believed and might've lived/hunted in breeding pairs or family units to better hunt and defend territory and whatnot (yay NatGeo & Discovery).
-built up speed in a short explosive burst and let its momentum and bulk plus teeth kill unwary prey like crocs and great white sharks.

 

[A Satanic Panda]

I'm still leaning toward scavenger too. It could have been territorial/defense kind of thing, like if the hadrosaurus was protecting its young.

And seriously guys, you can't observe one instance of something already pretty vague, and say it's proven something specific. That's not science.

 

[Artemicion]

It could have been territorial/defense kind of thing, like if the hadrosaurus was protecting its young.

If that was the case, the hadrosaurus would probably not have survived the attack. How many animals in nature can you name that would protect their young only so long as they didn't sustain an injury?

If you answered "none", you're correct.

 

[Miss G.]

-hunted similarly to a komodo dragon, also big and not fast, by biting and infecting its prey (the valleys in its teeth more than likely carried accumulated bacteria from scavenged meals)

This is an old assumption, they actually have a poisonous bite. Its been known for quite a while now.
https://en.wikipedia.org/wiki/Komodo_dragon

I know komodos have poisonous bites, I was referring to the T-rex's bite as something infectious because of its eating habits and the numerous places in its teeth to collect harmful bacteria. That's why I said 'similarly' instead of 'exactly'. The point is it can bite something, let the bleeding and whatever else in its bite do all the work and then settle down for an easy meal, like a komodo would. Imagine a gaping wound inflicted by a mouth that big, coupled with bacteria from previous kills getting into it whilst the prey is trying to not bleed out... not pretty.