Could horns or antlers evolve on a predator?

[Bulldog Psion]

To continue with my habit of occasionally posting what seem to me to be interesting questions on various biology or archaeology topics ...

Could a predator ever evolve horns or antlers?

This picture (http://2.bp.blogspot.com/-ioK1Im4zW0k/UtwWgzoJKEI/AAAAAAAAJn8/qcDfF6dT6mE/s1600/junglecatdude.jpg) inspired me to ask the question, basically. :smallbiggrin:

While the idea of a horned predator is interesting to me simply because of its "weirdness factor" and so forth, I can't really see how it could occur in a natural species even on a fantastic world.

Horns and antlers appear to me to be defensive weapons for herbivores, which lack fangs and claws with which to enter combat. As such, barring "a wizard did it," I simply can't see why such structures would evolve on a predatory species, much as I like the notion.

Does anyone have any thoughts on the topic, pro or con?

[crayzz]

That's actually an interesting point: I had never noticed that most anything with horns is a herbivore.

I dunno about horns, but wild boars have tusks and they eat meat. They're not particularly predatorial, but I don't see why an accident of evolutionary history couldn't produce a more predatorial version, and by analogy a similar creature with horns instead of tusks.

[LibraryOgre]

Basically, you develop pointy bits because you need them to hunt or because you need them to defend against hunting.

Horns, as they go, are somewhat inefficient hunting tools, but you could wind up with them on a predator, especially if the predator is also something's prey.

EDIT: A quick search for "horned predators" turns up the Carnotaurus. (http://en.wikipedia.org/wiki/Carnotaurus)

[cobaltstarfire]

I guess not technically a "horn" since it's a modified tooth, but Narwhals are predators, and they have a thing that projects from their face and is stabby.

Lots extant reptiles have horns too, and most of them are predators. There were some carnivorous dinosaurs that had horny projections on their heads too

The cask on a cassowary is pretty similar to a horn anatomically.


I think it's possible, though really unlikely. But if some carnivore starts developing some horn bits, and they help it survive better, and they don't hurt its chances of finding a mate then yeah maybe?

[madtinker]

I know walruses use their tusks for grubbing up food from the sea bed. Not a very exciting predator, but I think it counts.

[Bulldog Psion]

I know walruses use their tusks for grubbing up food from the sea bed. Not a very exciting predator, but I think it counts.

I believe they occasionally stab smallish seals to death with them also, though I read that years ago and it might have been disproved since.

[Yora]

My first thought was walrus, whose tusk are not used for catching fish, as far as I know. It's teeth and not horn, but any creature that "evolves horns" independently from existing horned animals would only have something "comparable to horns".
Since we consider squid eyes and insect eyes to be "eyes", even though they evolved independently from vertebrate eyes, "comparable to horns" would make it "horns" by that logic of describing body parts.

Since horns on herbivores have nothing to do with feeding, there is no reason why predators couldn't have them. And feeding is the only difference that defines herbivores and carnivores.

[TwistInTheMyth]

There are several examples of animals evolving ridiculous physical characteristics for various reasons, evolution can take really weird routes sometimes. I could see some sort of decorative horns evolving on a predator as an intimidation factor, or to impress mates. Like the male lion's mane--it basically exists to look threatening and serves no direct purpose (that I know of, at least). For creating a fantasy creature, if you can come up with a reason for your predator's distant ancestor to have horns (protection from a bigger predator? evolution from an omnivore?), you could argue that they were vestigial from that time, or kept due to sexual selection.

[Flickerdart]

Like the male lion's mane--it basically exists to look threatening and serves no direct purpose (that I know of, at least).
Isn't the mane to make it more difficult for competing males to claw or bite the neck when fighting?

[Lord Torath]

I'd agree that horns are more of a defensive measure. Predators want hooks to catch and hang on to prey, and so have backward-curving claws and fangs. Horns seem more likely to puncture and slide back out, inflicting damage, but releasing the target. This gives the horned animal a way to inflict damage on its attacker without locking the two together, giving it the ability to flee.

Regarding Narwhals, I'm pretty sure they don't use their horns for hunting. Having your food stuck on the end of a long pole with no hands to pull it off and put it in your mouth seems counter-productive.

[HandofShadows]

Isn't the mane to make it more difficult for competing males to claw or bite the neck when fighting?

I do know it's why the females do the hunting. The mane makes the males easier to see.

[Bulldog Psion]

Good, this is proving to be an interesting discussion. I like coming across a topic that people seem to enjoy talking about. :smallsmile:

Looking again at the creature I linked there, I can see those horns serving for intraspecific dominance and/or protecting the back of the neck from bites. Perhaps evolving from a smaller, horned omnivore whose horns gave it something of a chance against some neck-biting predator; then, once a shift was made from omnivore to carnivore, and size increased to help with prey handling, the horns could switch over to a mainly social/breeding function.

I suppose it's possible that horns appeared on herbivores due to their greater utility there, but it may also be arguable that they are absent on our world's carnivorous mammals largely due to their simply, accidentally being a hornless group which evolved predatory habits. Which is an odd but interesting thought.

Edit: mind you, I personally think that herbivores would still develop horns much more commonly than carnivores, but this discussion has convinced me that carnivore horns probably aren't impossible, but would represent a corner case rarity that could actually exist once in a while.

[cobaltstarfire]

Regarding Narwhals, I'm pretty sure they don't use their horns for hunting. Having your food stuck on the end of a long pole with no hands to pull it off and put it in your mouth seems counter-productive.

Yes they do, it's a sensory organ, last I read about them that was only a theory, but it looks like more research has been done on it since I sat in the school library and read all the cetacean literature available. :smalltongue:

It's also believed they have some funtion in sexual selection.

Horns and antlers and things don't necessarily have to be used to stab things, they usually have multiple functions and evolved from numerous evolutionary pressures not from a single one.

[Tvtyrant]

What if it is not an apex predator? Something like a house cat with a unicorn horn would be hard to attack by wolves/birds of prey.

[zabbarot]

I believe they occasionally stab smallish seals to death with them also, though I read that years ago and it might have been disproved since.

Some walruses eat seals habitually. Mostly ringed and bearded seals apparently. They don't use their tusks though.

They have incredibly powerful tongues which they can pump like a piston to create suction. This is to help them eat clams/bivalves by effectively sucking them out of their shells. The suction is strong enough to rip a seal apart though. It's like some horrid version of the dementors' kiss of death, just pucker up then get flipped inside out.

[Soras Teva Gee]

Wouldn't a horn break?

I mean if you were using it more/less everyday to hunt your dinner. You prey twists wrong they're everything is big enough to have leverage and snap it off seems to me. Claws grow back and a tooth being more compact and more likely to just move the whole predator around. While stabbing and withdrawing allows the prey to potentially get away, which even if it dies later doesn't put food in the predators belly. And if it breaks its kinda a big resource investment that you need to obtain resources. I think you need to be a human and able to make more spears at need to make them effective hunting weapons. (Also we're the freaking Terminator of the animal world and can walk wounded prey to death)

A herbivore isn't going to need them as often and stabbing is pretty good for warding things off.

So a display feature would seem the only possiblity and predators don't seem to have many of those either, probably an efficiency thing too.

[Lord Torath]

What if it is not an apex predator? Something like a house cat with a unicorn horn would be hard to attack by wolves/birds of prey.
I do know it's why the females do the hunting. The mane makes the males easier to see.I suspect having a big horn on the top of your head could serve a similar purpose as the lion's mane, making it harder for you to sneak up on prey. Most of our small predators do not have defensive horns, suggesting they might not be very useful for a predator, even if it's prey to larger predators. (Note that I'm not including exoskeleton-equipped predators here.)

[MorgromTheOrc]

I'm now imagining some kind of horrific fast running/swimming/flying animal that quickly darts out and harpoons prey with one or two hooked horns then rips away at them with little grabber hands.

[Killer Angel]

I'd agree that horns are more of a defensive measure.

Horns are, indeed, defensive. So it's kinda wasted on a predator.

Antlers serve more as a display of strenght in sexual selection (male-male competition and female-mate choice). So it could be more likely even for a predator.
BUT, in this case, the bigger the better, and for predators, big antlers could easily be counterproductive for hunt.

[weaseldust]

Swordfish kind of have horns and even use them to kill their prey. Maybe you want a land predator? Could there be a terrestrial equivalent of a swordfish, like a lion with a long 'sword' on its head? I'd say so - the 'sword'/horn might be useful for flailing around in a dense flock of birds to knock some out of the sky, or for tripping running antelope.

There are also plenty of small carnivores that have spines. All you need for them to have horns is for the spines on their head to become large and few in number. Thorny dragons (which are carnivores) are already a bit like that - if you just looked at the head, you might say it was horned, though they have spikes like that all over their bodies.

[paddyfool]

Big horns or antlers could be tricky for an ambush predator. If a lion's mane makes it too visible, a great big pair of antlers would be worse. Unless a key part of its hunting tactics was to prey on a species that looked similar, right down to the antlers, maybe? The two could even potentially have evolved from the same common ancestor (some great apes, e.g. Gorillas, are vegetarian).

[Bulldog Psion]

Big horns or antlers could be tricky for an ambush predator. If a lion's mane makes it too visible, a great big pair of antlers would be worse. Unless a key part of its hunting tactics was to prey on a species that looked similar, right down to the antlers, maybe? The two could even potentially have evolved from the same common ancestor (some great apes, e.g. Gorillas, are vegetarian).

That's a fascinating idea. Kind of like an ant-mimic spider but on a grand scale! I think you've come up with the most original notion in the entire thread so far. :smallcool:

[Avilan the Grey]

Outright horns, as we think of them, have never evolved on predators. Except on Chameleons (as far as I know).
My personal guess is that it's because predators do not need them as weapons. However horns and antlers have a secondary function: To be sexually attractive. Horn-like growths have certainly evolved on predators. Somebody brought up Carnatosaurus. Other dinosaurs had them as well:
Several species closely related to T-rex had strong bone ridges on their heads that most likely was used in "pushing matches" where they pushed heads against each other to determine strength.
Dilophosaurus was another more obvious example where the ridges were probably used as display surfaces.
Not to mention Guanlong...

In fact, growths like this seems to be far more obvious on lizards, dinosaurs and well... modern dinosaurs (birds).

Of course we can also go into the grey zone and find several species of omnivores with impressive weaponry, like different kinds of wild pigs (yes, they eat meat. Yes, several species will actively hunt for small animals if hungry enough).

[hamishspence]

Of course we can also go into the grey zone and find several species of omnivores with impressive weaponry, like different kinds of wild pigs (yes, they eat meat. Yes, several species will actively hunt for small animals if hungry enough).

Some species of deer and some species of antelope also qualify as "omnivorous and will actively hunt small animals".

[Yora]

Horns and antlers and things don't necessarily have to be used to stab things, they usually have multiple functions and evolved from numerous evolutionary pressures not from a single one.

I don't even know of any case of a species of animal using horns to inflict injury on a somewhat regular basis. Most commonly they seem to be used by male animals to fight other male animals of the same species, and those fights are more like wrestling. Horns can cause injuries by puncturing flesh, but to my knowledge none are made for that purpose. It's more bad luck on the part of the animal or person who gets stabbed.

[hamishspence]

Rhinos maybe? Their horns are hardened masses of hair rather than bone though.

[Avilan the Grey]

I don't even know of any case of a species of animal using horns to inflict injury on a somewhat regular basis. Most commonly they seem to be used by male animals to fight other male animals of the same species, and those fights are more like wrestling. Horns can cause injuries by puncturing flesh, but to my knowledge none are made for that purpose. It's more bad luck on the part of the animal or person who gets stabbed.

Antelopes and deer will use horns for defence against predators. It is not, however usually their first attempt. It usually goes "Flee - Try to Kick - Horns". There are instances though where fighting is necessary (https://www.youtube.com/watch?v=yGhRbZUzN5A)...

Cows and buffalo on the other hand will use their horns, and the weight behind those horns, as their first line of defense, offense, and for passing time.
As we have discussed before here... If you stumble into a normal, domestic farmstead and get between a calf and a group of ordinary milking cows that even get a slight inkling that you might do harm, you better clear that fence and fast.
Cows and buffally will not stop attacking until you run away, far away, or you are stomped into the ground and not moving (and probably leaking stuff from your belly).

Edit: Rhinos are somewhere in between deer and buffalo. Aggressive yes, but not as... thorough.

[Bulldog Psion]

As we have discussed before here... If you stumble into a normal, domestic farmstead and get between a calf and a group of ordinary milking cows that even get a slight inkling that you might do harm, you better clear that fence and fast.

Yes, the idiom "mess with the bull, get the horns" is probably one of the most accurate proverbs ever. :smallwink: And it doesn't take a bull, as you note -- a cow will do just fine. Bovids are an aggressive lot, really. They only look peaceful when they're grazing, but I'm sure a prizefighter looks pretty tranquil eating a sandwich, too. :smallwink:

[cobaltstarfire]

I don't even know of any case of a species of animal using horns to inflict injury on a somewhat regular basis. Most commonly they seem to be used by male animals to fight other male animals of the same species, and those fights are more like wrestling. Horns can cause injuries by puncturing flesh, but to my knowledge none are made for that purpose. It's more bad luck on the part of the animal or person who gets stabbed.

Some bovine horns were found to have evolved for self defense more than for sexual selection. I dunno if you saw the thread last year of "are horns weapons" or whatever, but someone posted a paper on it....if the paper wasn't in that thread, I must have just found and read it independently.

But yeah, animals use their horns for many things, and that includes stabbing.

[The Second]

It's pretty doubtful that a predator species would have horns/antlers - even if the horns were a holdover from some earlier evolutionary cousin. Horns and antlers are a big investment; it takes a large amount of resources to grow and maintain even a moderately sized rack of antlers or a strong set of horns. All of those resources are better saved for hunting.

A second problem is that horns and antlers have a nasty tendency to get tangled up in brush or tall grasses, the kind of terrain where most predators hang out while stalking prey. In the case of antlers, they increase the profile if whatever animal sports them, and an increased profile means that stalking, or even hiding and waiting to ambush, is much more difficult. If a creature can't stalk or hide, that means even more wasted energy on having to run prey into the ground.

[Avilan the Grey]

It's pretty doubtful that a predator species would have horns/antlers - even if the horns were a holdover from some earlier evolutionary cousin. Horns and antlers are a big investment; it takes a large amount of resources to grow and maintain even a moderately sized rack of antlers or a strong set of horns. All of those resources are better saved for hunting.

As I said, the only pure predator that has proper horns, and use them against each other in fights I know if is the three-horned chameleon (https://www.youtube.com/watch?v=aY8J05KzZZo). No mammals.

[Bulldog Psion]

So I guess my initial doubts were correct, then?

[Avilan the Grey]

So I guess my initial doubts were correct, then?

Don't ruin an interesting discussion by summarizing it. :smallwink:

[Bulldog Psion]

Don't ruin an interesting discussion by summarizing it. :smallwink:

That is preeminently quotable. Do you mind if I make that my signature in place of my current one? :smallsmile:

[Avilan the Grey]

That is preeminently quotable. Do you mind if I make that my signature in place of my current one? :smallsmile:

Do with it as you please :smallsmile:

[Kato]

Hm... Might be a dumb question but are there animals that are not ruminantia (I actually had to check that word because I never needed to know what "Wiederkäuer" is in English. Nor did I realize they are such a large taxonomic group) with actual antlers? I mean, apart from the odd beetle that has something that reminds you of antlers and ths it's called it. I guess horns being a bit more general term and widespread occur more often... Tusks are possibly even more common - among animals with teeth anyway - but not really horns or antlers.
Anyway, I guess the small number of horned predators is a bit curious but then they aren't great tools for killing, not if you have claws or fangs or talons or such. Makes you wonder why prey species have them for defense indtead of more useful things. Like fangs, claws or talons :smalltongue:

[Lord Torath]

It looks like only members of the Deer family (Cervidae) grow antlers. Antlers are different from horns in that the antlers are shed and regrown every year. Horns have a core of living bone growing out of the skull.

Claws and talons are really great for grabbing and holding on to something, so you can then bring your sharp teeth or powerful jaws to bear. Most prey animals don't want to hold on to their predators, but would rather inflict damage and then get away. Horns are great for this. You can concentrate force over a very small area, but there is little chance of your target getting entangled on a single (or possibly dual) protrusion.

[zabbarot]

It could also be related to how many predators rely on ambush tactics. It's probably easier to defend your neck by flailing horns/antlers than trying to get a leg up there to claw them. And if something just runs up and jumps on your back claw and teeth don't do much good either.

How many prey animals hold their ground? Most just run away don't they? Large herds sort of use a mix of running, and charging to keep the tougher meaner animals between the predator and the younger/weaker ones. I guess that could be part of why most horns are forward facing as well.

[Bulldog Psion]

Claws and talons are really great for grabbing and holding on to something, so you can then bring your sharp teeth or powerful jaws to bear. Most prey animals don't want to hold on to their predators, but would rather inflict damage and then get away. Horns are great for this. You can concentrate force over a very small area, but there is little chance of your target getting entangled on a single (or possibly dual) protrusion.

That's true -- while horns serve well as weapons, particularly with the momentum of a large body behind them, they are essentially useless for "prey handling." Conversely, carnivorous dentition is lousy for processing vegetative food, and claws have less utility than hoofs for rapid flight. You make a very good point.

And, of course, horns and antlers make a killing bite to the nape of the neck or through the cranium itself a much more difficult proposition.

[Feddlefew]

Horned Lizards (http://en.wikipedia.org/wiki/Horned_lizard) are predators with both spines (modified scales) and horns. They're ambush predators of ants that hunt by sitting next to the ant hill and picking off passing individuals, so their horns and spines are to discourage larger animals from grabbing them while they're sitting out in the open.

So, if you want a predator with horns, think small, angry lizards that squirt blood from their eyes.

[sktarq]

In our world the Lizards with horns (in a couple groups) would be the only only land animals that I think everyone would agree are both carnivores (as opposed to say deer who eat birds on north sea islands for example) and who have horns/antlers/something most people would call a horn (to include Rhinos and various giraffe cousins)

When you go underwater or into the invertebrates definitions of "horns" becomes problematic but examples could be found.

Also while most horns in mammals are used for intra-species dominance battles (and weapons used by carnivores to find food are probably better energy sinks than a second way to defeat rivals) some do use their horns for defence before flight at least some of the time. While the bovids dominate such a list, rhinos and muskox (which is part of the goat/sheep branch of hoofed mammals) both use their weaponry flat out defensively on a regular basis.

So if a carnivore did have horns they would probably A: not be used for inta species dominance fights as their predatory weapons would work better and so need another purpose or B: their hunting weapons are not well equipped to work on a target like a member of the same species-like the chameleon mentioned

Also since horns and their ilk in mammals are basically limited to hoofed mammals you'd have to have the branch of mammals best at digesting plant matter turn into a carnivore (which happens-see pigs or further back whales but is uncommon enough to stack the odds against it.

[cobaltstarfire]

Also since horns and their ilk in mammals are basically limited to hoofed mammals you'd have to have the branch of mammals best at digesting plant matter turn into a carnivore (which happens-see pigs or further back whales but is uncommon enough to stack the odds against it.

And even then it seems more likely for their teeth to do a thing, sort of like with hippos...who munch on grass all day, yet have giant killer teeth to deal with anything that threatens or even mildly irritates them.



Though poking about I found that some mammals (including humans) get little horny growths on their heads, I assume because of some weird genetic condition. So the potential is there, just not the selective pressure.

[BannedInSchool]

If a moose suddenly became carnivorous it's antlers wouldn't be too useful, is how I look at it. Also, as a predator relying on your horns or antlers to eat you'd be pretty screwed if they got broken. Sure, they can break teeth and claws, but not 50% in one incident usually.

[Bulldog Psion]

At the risk of summarizing and spoiling a good discussion yet again :smallbiggrin: it still looks, any way you slice it, that no horned carnivores could ever evolve naturally. The closest things would be knobby-faced stuff like ceratosaurs or entelodonts.

[Razade]

At the risk of summarizing and spoiling a good discussion yet again :smallbiggrin: it still looks, any way you slice it, that no horned carnivores could ever evolve naturally. The closest things would be knobby-faced stuff like ceratosaurs or entelodonts.

The issue here is that Evolution doesn't select for things. It selects against things. If a carnivore had horns and it didn't effect their ability to do what they did then they'd keep them around.

[NightScar]

Everyone seems to be thinking of static horns, but what about some kind of piston like horn? I thought of jellyfish while reading trough this discussion and how their stinger cells shoot out tiny inside out harpoons. that;s how I would envision a horned predator. It has the horn sequestered in flesh to decrease its silhouette and shoots it out like spring loaded punching javelin thing when it sneaks up on prey.

Could even be detachable like deer antlers (but at the predators whim). Example, they could activate the mechanism "firing" the horn to it's full length, impaling the prey and locking it down so they can't get away while the predator uses teeth/claws to finish the job.

[sktarq]

Well the longer I've been thinking about it one option did come to mind. If a predator dealt with intra-species challenges via first intimidation and then face to face challenges a frill like set of horns could be rather useful. Styracosaurus style.
Also if the horn was used for breaking into logs, termites, etc a horn could be pretty useful.

[Razade]

Everyone seems to be thinking of static horns, but what about some kind of piston like horn? I thought of jellyfish while reading trough this discussion and how their stinger cells shoot out tiny inside out harpoons. that;s how I would envision a horned predator. It has the horn sequestered in flesh to decrease its silhouette and shoots it out like spring loaded punching javelin thing when it sneaks up on prey.

Could even be detachable like deer antlers (but at the predators whim). Example, they could activate the mechanism "firing" the horn to it's full length, impaling the prey and locking it down so they can't get away while the predator uses teeth/claws to finish the job.

Mostly because animals aren't machines and that's not how Jellyfish stings operate. How would the predator put the horns back into what ever flesh pack they had? How would something like that even evolve? Jellyfish stingers, as per your example, are one use cells that react to animals running into them. They're not fired manually by the Jellyfish (since jellyfish don't have brains).

[NightScar]

Mostly because animals aren't machines and that's not how Jellyfish stings operate. How would the predator put the horns back into what ever flesh pack they had? How would something like that even evolve? Jellyfish stingers, as per your example, are one use cells that react to animals running into them. They're not fired manually by the Jellyfish (since jellyfish don't have brains).

The jellyfish was just a springboard for my thought process. Though i like the idea of some sort of triggered mechanism.

Cats have retractable claws. Other animals like scorpions, pistol shrimp, and mantis shrimp use more 'mechanical' ways of subduing prey. I'm just thinking outside the box.

EDIT: With a little further thought, maybe detachable horn that's like a bee stinger crossed with a proboscis. Something that impales and breaks off, but then has a channel where it bleeds the target.

[cobaltstarfire]

Bee stingers aren't really a great thing to run with...since the bee dies in using its sting.

Broken horns are a rather bloody and painful affair, at least where cows horns and such are concerned.

A horn like a Rhino's strikes me as something that would be too costly in terms of nutrients and time.

Antlers can grow really fast, but they're still likely cost prohibitive for a predator.

[NightScar]

I was just using Bee's to get the image across, I didn't mean to communicate that the horn would be attached to anything vital. Maybe an exothermic creature could make use of the breakaway horn due to lower overall energy use. Counteract the costs of making it by only using it when you catch the big prey meal and not eat again the rest of the month while you regrow it.

As for nutrient cost, herbivores are able to maintain a set of antlers or horns, so I don't see why a predator that had evolved a predator focused variation would have any more trouble (just energetically speaking, putting aside pitfalls like exposing ambush predators). Perhaps the answer lays in the different trophic levels of herbivores and carnivores. Maybe large size carnivores can't get enough energy from their territories to develop large weapons in general. All the standard predators that spring to mind (bears, wolves, sharks) all use relatively small claws and teeth compared to antlers.

EDIT: Typo

[cobaltstarfire]

As for nutrient cost, herbivores are able to maintain a set of antler's horns, so I don't see why a predator that had evolved a predator focused variation would have any more trouble (just energetically speaking....).

I don't think you understand how horns or antlers work, or the difference between an animal that can forage/graze all day at little cost, vs an animal that must hunt for its food and will fail on most attempts.

Horns are innervated with large blood vessels, you don't just break a horn off and grow it back. You break it off and then you bleed out. And if you don't die, it's not going to grow back.


Antlers grow fast but that's relatively speaking. It's a thing spread out over the course of many months, and are dependent on ones fitness and availability of nutrients. You need about 2-3 months just to grow as many inches of antler. And during that time of growing if you don't have access to nutrients you're not going to grow very much in the way of antler.

[Feddlefew]

Bee stingers aren't really a great thing to run with...since the bee dies in using its sting.

Only honey bee workers die when they sting. Queen honeybees can sting as many times as they need to, and the same goes for all other bee species, like bumble bees and solitary bees. Wasps and ants also can sting as many times as they want.

But this is getting off track, since stingers don't have too much in common structurally with horns.

Edit: And no, jellyfish stings don't work like that. They're microscopic venom-filled tubes that turn inside out via chemical reaction, and they need to be replaced after each use.

[NightScar]

I don't think you understand how horns or antlers work, or the difference between an animal that can forage/graze all day at little cost, vs an animal that must hunt for its food and will fail on most attempts.

Horns are innervated with large blood vessels, you don't just break a horn off and grow it back. You break it off and then you bleed out. And if you don't die, it's not going to grow back.


Antlers grow fast but that's relatively speaking. It's a thing spread out over the course of many months, and are dependent on ones fitness and availability of nutrients. You need about 2-3 months just to grow as many inches of antler. And during that time of growing if you don't have access to nutrients you're not going to grow very much in the way of antler.

I didn't mean to imply I knew anything about antler or horn anatomy, which is why I went straight to purely hypothetical. Just jumping in on some interesting discussion. I was not aware horns had living cores, i had assumed they and antlers were just dead keratin. The point i was getting at with"energetically speaking" was it would cost the same amount of calories for a predator to grow horns.

As for regrowing antler's, i was thinking of something with a biology similar to a large snake that eats once every few weeks or a month and could use the energy to regrow antlers. Though if they grow only a few inches in that time, i guess that model is out as well.

and i just noticed my "antler's horn" typo. meant to be "antlers or horns"


Edit: And no, jellyfish stings don't work like that. They're microscopic venom-filled tubes that turn inside out via chemical reaction, and they need to be replaced after each use.

harpoon was a poor choice of words on my part. I was hoping "inside out" would clarify, but that is what i meant.

[Lord Torath]

If you're going to us something like horns/antlers for hunting, you're going to need a good way of replacing "expended ammunition." If you have a slow metabolism, you might be able regrow an antler in time for your next meal, but having a slow metabolism means you probably don't grow things very quickly. Antlers take a lot of energy to grow, so each kill would have to be big enough to both sustain the animal until its antler is replaced, and provide enough energy to regrow the antler.

It's an interesting idea, but unless you're "Spike" from X-Men 3 or Dr. Conners from Spiderman, you're not going to be regrowing antlers before you need your next meal.

[Solaris]

Saber teeth are easily as costly as horns, likely as bloody and painful to break, and just about as likely to break to boot, and they've evolved several times in predatory mammals. Many of these predators were highly successful until climate change or a depletion of prey species wiped them out.

[Lord Torath]

But sabre teeth are only part of the arsenal. Even if you took all 4 canines away from a "sabre-toothed tiger," it still possesses claws to grab prey, and powerful jaw muscles to lock its jaws around its prey's throat. It will be harder for the cat to hunt, but not impossibly so.

[JustSomeGuy]

This morning on radio 4 they were discussing evolution around deep sea vents and went on to snails/gastropods... from what i picked up on (had to interrupt listening a few times) there was a bit of an arms race between 2 groups which resulted in one snail with actual iron plating and scales on its foot, and another that hasa venemous/poisonous horn it can shoot and reel in, harpoon style. Sounded legit, especially given the source.

How about a ram-raid style predator that needs to keep hold of it's prey after impact, it just speeds out of nowhere hoping to stab something in a school/herd/flock/whatever and dissapears off into the ether again, with a youngling now gone from the group. It attacks out of the low sun or high clouds or cliff tops or something, maybe on a trail or near water?

[Solaris]

But sabre teeth are only part of the arsenal. Even if you took all 4 canines away from a "sabre-toothed tiger," it still possesses claws to grab prey, and powerful jaw muscles to lock its jaws around its prey's throat. It will be harder for the cat to hunt, but not impossibly so.

Smilodon had an uncommonly weak bite, and our theoretical horned predator would be at no less of a disadvantage due to still possessing its claws - on top of still having its carnivorous dentition intact.

[Avilan the Grey]

At the risk of summarizing and spoiling a good discussion yet again :smallbiggrin: it still looks, any way you slice it, that no horned carnivores could ever evolve naturally. The closest things would be knobby-faced stuff like ceratosaurs or entelodonts.

Ah. But we have already presented evidence of horned predators. Again, the chamelion. It is 100% carnivorus and do jousting matches with it's horns for territory and mating rights.

Hower outside the reptile kingdom there are... none that I can think of.

[WolfLordBran]

One possibility I've thought up is instead of a longer horn the predator in question would possess a shorter horn on its nose ala Triceratops. Rather than using it to gore the prey entirely through, our hypothetical predator uses it to run along side the prey and slashes the abdomen open. While not an instantaneous kill, the newly eviscerated/bleeding prey animal would quickly collapse and the predator could simply walk over and begin to feed.

I'm picturing a relatively low-slung animal who doesn't need to be a long distance runner but have a good short range sprinting ability. Still prolly an ambush predator but it could lounge somewhere until prey came by at which point it could sprint out, open up the unlucky sod it's gonna eat and wait for the animal to collapse from shock/blood loss/evisceration.

[cobaltstarfire]

Only honey bee workers die when they sting. Queen honeybees can sting as many times as they need to, and the same goes for all other bee species, like bumble bees and solitary bees. Wasps and ants also can sting as many times as they want.



Yeah and the difference is that one loses its stinger and the other doesn't.

[Dire Moose]

Basically, you develop pointy bits because you need them to hunt or because you need them to defend against hunting.

Horns, as they go, are somewhat inefficient hunting tools, but you could wind up with them on a predator, especially if the predator is also something's prey.

EDIT: A quick search for "horned predators" turns up the Carnotaurus. (http://en.wikipedia.org/wiki/Carnotaurus)

Carnotaurus and Ceratosaurus (http://en.wikipedia.org/wiki/Ceratosaurus) (whose name literally means "horned lizard") are probably the best-known horned predators.

And although they're not technically horns or antlers, Dilophosaurus (http://en.wikipedia.org/wiki/Dilophosaurus), Cryolophosaurus (http://en.wikipedia.org/wiki/Cryolophosaurus), and Guanlong (http://en.wikipedia.org/wiki/Guanlong) all had flashy head crests.

So yes, there are documented examples of predators with elaborate headgear, but exactly what they were doing with it is difficult to tell from fossils.

And then, while not headgear, elaborate back sails/ridges have shown up in things like Dimetrodon and Spinosaurus.

EDIT: Just noticed this:


One possibility I've thought up is instead of a longer horn the predator in question would possess a shorter horn on its nose ala Triceratops. Rather than using it to gore the prey entirely through, our hypothetical predator uses it to run along side the prey and slashes the abdomen open. While not an instantaneous kill, the newly eviscerated/bleeding prey animal would quickly collapse and the predator could simply walk over and begin to feed.

I'm picturing a relatively low-slung animal who doesn't need to be a long distance runner but have a good short range sprinting ability. Still prolly an ambush predator but it could lounge somewhere until prey came by at which point it could sprint out, open up the unlucky sod it's gonna eat and wait for the animal to collapse from shock/blood loss/evisceration.

Ceratosaurus does indeed possess a short nose horn as stated above, and it has the general profile of a low-slung, short-range sprinter you mentioned (link (http://th09.deviantart.net/fs70/PRE/i/2013/196/b/e/ceratosaurus_growth_series_by_scotthartman-d2wl57m.jpg)). However, if it wanted to eviscerate abdomens it had some of the longest and sharpest teeth in the dinosaur group and would more likely have just used them.

[sktarq]

Two more thoughts-

On the whole "stinger" idea. A head based venom injector that is not mouth based would be theoretically possible but outside the arthropods I don't see anything to evolve from really. Could be very horn-like but unless the scent gland somehow evolved toxicity I'm not sure what it could evolve from.

Also Birds-depending on where you start defining "horns" some hornbills may qualify (there are hornbills with various diets) and other horn crests and cassowary like structures have been seen in fossils.

[LibraryOgre]

On the whole "stinger" idea. A head based venom injector that is not mouth based would be theoretically possible but outside the arthropods I don't see anything to evolve from really. Could be very horn-like but unless the scent gland somehow evolved toxicity I'm not sure what it could evolve from.


Starting with a cervid, you might have a creature that keeps its velvet longer, perhaps "sweating" out something in its diet that has a low toxicity? That toxicity could lodge in the bones, leading to velvet-covered antler stabs being mildly toxic, and bony antler stabs being moreso.

[Solaris]

Starting with a cervid, you might have a creature that keeps its velvet longer, perhaps "sweating" out something in its diet that has a low toxicity? That toxicity could lodge in the bones, leading to velvet-covered antler stabs being mildly toxic, and bony antler stabs being moreso.

Something like that. Sweat glands evolved into mammary glands, after all, so it's not entirely unreasonable to have a sweat gland evolve into a venom gland. Heck, our sweat glands already have an antimicrobial effect with helping to produce the acid mantle.

Platypuses and slow lorises also have toxin glands that are unrelated to their salivary glands. Skunk musk is also considered poisonous, and is also unrelated to the salivary glands.

[Lord Ruby34]

What about a predator species that wasn't an ambush hunter or an apex predator? Something that tended to kill it's food by running it to death in packs, but had to be wary of ambush predators? The horns or antlers wouldn't be used to hunt prey, but would instead be used as a last line of defense when attacked. The species would still have claws and teeth (or maybe the ability to use tools like humans, though I shudder to think what the apex predator would be if it wasn't the race with the ability to use and develop tools). The problem I can immediately see is that large appendages on the head would probably make running awkward.

Disclaimer: I know very little about biology.

[Lord Torath]

What about a predator species that wasn't an ambush hunter or an apex predator? Something that tended to kill it's food by running it to death in packs, but had to be wary of ambush predators? The horns or antlers wouldn't be used to hunt prey, but would instead be used as a last line of defense when attacked. The species would still have claws and teeth (or maybe the ability to use tools like humans, though I shudder to think what the apex predator would be if it wasn't the race with the ability to use and develop tools). The problem I can immediately see is that large appendages on the head would probably make running awkward.

Disclaimer: I know very little about biology.Many animals manage to run quite well with horns or antlers on their heads, so I don't think that would be too much of an issue. However, a predator with horns or antlers is less effective against other animals with antlers or long horns. The predator's horns can be blocked or tangled in their prey's horn/antlers, making it harder to get a kill. This would encourage prey animals to grow horns or antlers.

[Knaight]

Smilodon had an uncommonly weak bite, and our theoretical horned predator would be at no less of a disadvantage due to still possessing its claws - on top of still having its carnivorous dentition intact.
Felines in general (from smilodon to tigers to house cats) tend to have fairly weak bites for their size. That "for their size" caveat is important, as the bites are generally still more than strong enough to handle their prey, particularly given that they do have the other muscles needed to tear well once gripping, and they've got claws.

[BannedInSchool]

Felines in general (from smilodon to tigers to house cats) tend to have fairly weak bites for their size.
Compared to other apes we've traded bite strength for brain size, and the smaller the cat the more they've gone that way too. Umm, not really relevant to this thread but I think those are interesting tidbits. :smallsmile:

[cobaltstarfire]

Felines in general (from smilodon to tigers to house cats) tend to have fairly weak bites for their size. That "for their size" caveat is important, as the bites are generally still more than strong enough to handle their prey, particularly given that they do have the other muscles needed to tear well once gripping, and they've got claws.

Well they don't really need a strong bite, the teeth in a cats bite are the important part...they just need to be able to hold on long enough for the prey to die.

If all cats have a weak bite relative to their body size though I would imagine that smilodons have an even weaker bite relative to their size, otherwise it wouldn't have been a surprise to the folks who did the bite force measures.

That said last I read on them, scientists still aren't entirely sure why smilodons have those big saber teeth, or how entirely they would have been used.

[Bulldog Psion]

That said last I read on them, scientists still aren't entirely sure why smilodons have those big saber teeth, or how entirely they would have been used.

One interesting theory (http://file.scirp.org/Html/6-1400102_27414.htm) I've seen put forward is that their primary goal was to cause "pneumothorax" -- that is, a punctured, collapsed lung -- in the prey. As the article points out, some large herbivores suffer a double collapsed lung if just one is punctured, which is effectively an evolutionary design flaw. So rather than just being badly damaged by a puncture, those animals would collapse and asphyxiate almost immediately.

I can see some problems with that theory (for example, would such a narrow attack strategy evolve four separate times?) but it's an interesting "take" on the sabertooth phenomenon nevertheless, IMO.

[Solaris]

Felines in general (from smilodon to tigers to house cats) tend to have fairly weak bites for their size. That "for their size" caveat is important, as the bites are generally still more than strong enough to handle their prey, particularly given that they do have the other muscles needed to tear well once gripping, and they've got claws.

Like cobaltstarfire said, smilodons have a weaker bite than tigers and lions - about 1/3 the lion's, if memory serves. That isn't as disadvantageous as it sounds; a weaker bite reduces the risk of the smilodon breaking its teeth. The weak bite is also as a consequence of the jaw being adapted to gape unusually wide (120*, but don't quote me on that) to actually let the sabers come into play.

Mostly, though, smilodons took their prey by muscle and bulk. They were built much more robustly than other big cats.

[cobaltstarfire]

One interesting theory (http://file.scirp.org/Html/6-1400102_27414.htm) I've seen put forward is that their primary goal was to cause "pneumothorax" -- that is, a punctured, collapsed lung -- in the prey. As the article points out, some large herbivores suffer a double collapsed lung if just one is punctured, which is effectively an evolutionary design flaw. So rather than just being badly damaged by a puncture, those animals would collapse and asphyxiate almost immediately.

I can see some problems with that theory (for example, would such a narrow attack strategy evolve four separate times?) but it's an interesting "take" on the sabertooth phenomenon nevertheless, IMO.


It's not a huge problem, or rather it's happen before often enough, with animals that aren't even remotely related.

For example to the untrained eye it's apparently quite difficult to tell a thylacine skull from a dog or wolf skull, it's just convergent evolution.

[Feddlefew]

Like cobaltstarfire said, smilodons have a weaker bite than tigers and lions - about 1/3 the lion's, if memory serves. That isn't as disadvantageous as it sounds; a weaker bite reduces the risk of the smilodon breaking its teeth. The weak bite is also as a consequence of the jaw being adapted to gape unusually wide (120*, but don't quote me on that) to actually let the sabers come into play.

Mostly, though, smilodons took their prey by muscle and bulk. They were built much more robustly than other big cats.

Cats hunt larger prey by cutting off circulation to the brain, causing a brain stem stroke. It's more pinch than puncture, so it's been theorized that smilodon's fangs were to allow it to bite from the back of the neck and still cut off blood flow.

[sktarq]

Cats and in particular the round or cone toothed big cats have a variety of killing styles- covering nose/mouth to stop oxygen flow, crushing the windpipe, puncturing the brain (Jaguars on capybaras most famously but leopards on dogs and goats are very common). So one can't really say they have one style.

Since experiments with skull models on the throats of carcasses have shown that a single bite tends to sever several of the key carotids, jugulars, and windpipe group and it have little key effects on say bellies that is the best bet. Also since aiming at soft parts doesn't need the bite pressure needed for bone they wouldn't have been at a disadvantage (but teeth that aimed more to wound than hold wouldn't need a jaw to hold them in place like many modern panthera cats use)
And yes they were built much more heavily especially in the forequarters which implies that they used wrestling techniques to get access to a killing bite and maintain prey control instead of a bite.