My Ceratosaurus "pet theory"

Adam Khor

Hey guys how r u?

I'm no paleontologist- just an artist with a healthy obsession with dinosaurs XD- but since there are no rules against it, I thought I'd share an idea I had some time ago, about Ceratosaurus.

You know how Ceratosaurus was said by some scientists to have been semi-aquatic because of its low body, relatively short legs and flexible tail, right?
Well, that doesn´t make much sense to me, cuz the animal doesn´t seem to have many adaptations for an aquatic lifestyle. Its forelimbs for example are quite short, and its eyes and nose should be in the top of its head, I would believe.

But what Ceratosaurus DOES have is a set of particularly long, saber-like teeth, which to me, suggests it was hunting prey larger than itself. Even more, its longest teeth, I read somewhere, were grooved. (Now you must know where I'm going with this)...

My question is... what if Ceratosaurus was venomous?



Think about it. A low body and relatively short legs mean it wasn´t a runner- it wasn´t chasing after prey, but rather ambushing, which is what works best for a venomous animal.
Its huge "fangs" would allow it to bite deeply into huge animals (like camarasaurs or apatosaurs for example) and inject them with venom.

AND, the horns on its head may have been brightly colored, as a warning so that other larger predators such as Allosaurus and Torvosaurus which coexisted with it would know he was venomous and leave him alone.

Now, I know many dinosaurs had grooved teeth, but not all of them had particularly elongated "fang like" teeth like Ceratosaurus did. It looks to me like Ceratosaurus was doing something different to other theropods...



Also, some will say that such a large animal wouldn´t be venomous, but, I think Megalania was about the same size as Ceratosaurus, and if it was anything similar to modern day Komodo dragons and other monitor lizards, then it probably was venomous as well.

Just a thought, but makes a lot of sense to me (not biased! )

Rubecula

That is very well thought out and a good logical argument. It is a pity I can't really say you are right or wrong as I simply don't have enough knowledge.

hey just a thought, instead of injecting venom could it have been a vampire? Like the vampire bat is only bigger?:D

Well perhaps that is pushing it too far. Sorry.:(

Kess73

Komodos are not venomous in the true meaning of that term though. They have saliva with contains septic pathogens rather than a traditional venom, and it is not expelled through their teeth. The arguement that they were venom killers was pretty much discounted last year as was the discovery of venom sacs in terms of the venom being what brought down prey.



Interesting theory on the Ceratosaurus though. I always presumed that the longer teeth were to create deeper puncture wounds so that the intended prey would suffer from massive blood loss more quickly and go into shock.

A lot about it would support your theory of it having some kind of venom, but I think something like the Komodo's saliva might be more likely.

Agree on the idea that it hunted larger prey. Everything about it screams of an animal that did it's damage in one surprise bite, and then waited for it's prey to die/go into shock.

Alvin T. Grey

What I love about this field is that all opinions carry the same valdity. With the notable exception of J Horner.....

Ceratasaurus was contemporary with Allosaur and Torvosaur, both bigger dinosaurs. Towards the end of the Jurassic Ceratasaur numbers were low compared to the larger animals. My bet is that the advantage of venom in a Ceratasaur would allow them to be a much more successful preditor and as such might have tipped the ballance away from Allosaurus. However that isn't born out in the record.

steddyeddy

Kess73 wrote: »

Komodos are not venomous in the true meaning of that term though. They have saliva with contains septic pathogens rather than a traditional venom, and it is not expelled through their teeth. The arguement that they were venom killers was pretty much discounted last year as was the discovery of venom sacs in terms of the venom being what brought down prey.



Interesting theory on the Ceratosaurus though. I always presumed that the longer teeth were to create deeper puncture wounds so that the intended prey would suffer from massive blood loss more quickly and go into shock.

A lot about it would support your theory of it having some kind of venom, but I think something like the Komodo's saliva might be more likely.

Agree on the idea that it hunted larger prey. Everything about it screams of an animal that did it's damage in one surprise bite, and then waited for it's prey to die/go into shock.

Actually the Komodo dragon saliva bacteria vs venom arguement has taken a turn back to the venom theory. In 2009 a mri taken on a dragon indicated the presence of venom glands and in singapore a venom gland was taken from a deathly ill dragon. The gland was tested and it was confirmed to contain toxic proteins. This disputes the theory that Komodo vicitms died as a result of bacteria.

Kess73

steddyeddy wrote: »

Actually the Komodo dragon saliva bacteria vs venom arguement has taken a turn back to the venom theory. In 2009 a mri taken on a dragon indicated the presence of venom glands and in singapore a venom gland was taken from a deathly ill dragon. The gland was tested and it was confirmed to contain toxic proteins. This disputes the theory that Komodo vicitms died as a result of bacteria.

That is the theory that I mentioned as being disputed in 2010, and as far as I know the true venom theory was put out to pasture as the saliva was again listed as the secondary cause of damage from a Komodo attack after the primary attack of the bite.

Adam Khor

Alvin T. Grey wrote: »

What I love about this field is that all opinions carry the same valdity. With the notable exception of J Horner.....

Ceratasaurus was contemporary with Allosaur and Torvosaur, both bigger dinosaurs. Towards the end of the Jurassic Ceratasaur numbers were low compared to the larger animals. My bet is that the advantage of venom in a Ceratasaur would allow them to be a much more successful preditor and as such might have tipped the ballance away from Allosaurus. However that isn't born out in the record.

That's interesting... but it doesn´t rule out the possibility of venom. It could also be that at the end of the Jurassic, the landscape became more arid and an ambush predator like Ceratosaurus didn´t have many places to hide and hunt. Allosaurus and Torvosaurus being better adapted to walk long distances would have an advantage over Ceratosaurus.

steddyeddy

Kess73 wrote: »

That is the theory that I mentioned as being disputed in 2010, and as far as I know the true venom theory was put out to pasture as the saliva was again listed as the secondary cause of damage from a Komodo attack after the primary attack of the bite.

That theory wasnt discounted it was the saliva theory that was superceded by the venom theory. They do have venom and venom ducts thats proven. Komodo bites can take several weeks to kill large animals such as deer and pymgy elelphants (extinct) but it is now thought to be the venom that ultimatly finished them off. The bite is the primary cause of death for smaller animals. The toxic proteins found in komodo glands have the effects seen prior to death in large animals.

steddyeddy

Adam Khor wrote: »

That's interesting... but it doesn´t rule out the possibility of venom. It could also be that at the end of the Jurassic, the landscape became more arid and an ambush predator like Ceratosaurus didn´t have many places to hide and hunt. Allosaurus and Torvosaurus being better adapted to walk long distances would have an advantage over Ceratosaurus.

I often wondered how common venom is in dinosaurs. Some venomous and poisonous animals build up a level of toxins in their body by consuming smaller animals which contain toxins eg the poison dart frogs eat ants to build up formic acid to convert to toxin in the body thus making them poisonous.

Adam Khor

steddyeddy wrote: »

I often wondered how common venom is in dinosaurs. Some venomous and poisonous animals build up a level of toxins in their body by consuming smaller animals which contain toxins eg the poison dart frogs eat ants to build up formic acid to convert to toxin in the body thus making them poisonous.

Yes, that's what pitohuis and the few other poisonous birds (dinosaurs:D) do as well.

Venom is so common nowadays that I would be surprised if no dinosaurs were venomous. After all the age of dinosaurs lasted around 160 million years- more than enough for the group to give rise to quite a few venomous species IMO. They were also much more diverse than originally thought...
I think it will be hard to prove it though, considering that scientists didn´t discover that many living lizards (including monitor lizards and iguanas) were venomous until very recently, and all we have of dinosaurs are incomplete fossil remains...

Kess73

steddyeddy wrote: »

That theory wasnt discounted it was the saliva theory that was superceded by the venom theory. They do have venom and venom ducts thats proven. Komodo bites can take several weeks to kill large animals such as deer and pymgy elelphants (extinct) but it is now thought to be the venom that ultimatly finished them off. The bite is the primary cause of death for smaller animals. The toxic proteins found in komodo glands have the effects seen prior to death in large animals.

Byran Fry discounted the saliva theory when he pushed the venom theory in 2005 and in 2009. He has been the main voice in trying to puish the venom theory over the theory that the saliva contains septic pathogens despite the fact that his venom is actually closer in make up to a pathogen in many ways than a true venom.

In 2010 a new study was started that has since leaned towards blood loss being the final killer of larger animals attacked by the Komodo as the pathogens prevented the prey animal's blood from clotting, rather than poisoning from a venom in the truest sense of the word.

They also found that animals kept in captivity had less of the septic pathogens in their saliva and also less to noine of the venom present in their bites, based on retrieving meat that they had the komodos bite into.

What was speculated there was that in captivity the komodos often get much cleaner food and also get food that is ready to eat straight away, so their bodies adapt to that and don't need the anti clotting side of things to ensure their intended prey drops.

Will try to find a link to what has been published so far as part of the 2010 study as it now contradicts a lot of what Fry claimed to be total fact.

Alvin T. Grey

Adam Khor wrote: »

That's interesting... but it doesn´t rule out the possibility of venom. It could also be that at the end of the Jurassic, the landscape became more arid and an ambush predator like Ceratosaurus didn´t have many places to hide and hunt. Allosaurus and Torvosaurus being better adapted to walk long distances would have an advantage over Ceratosaurus.

It could also be explaind by a low reproductive rate/success rate in ceratasaur. But that is another unknown. Maybe they werent that common to begin with.

Now lets consider the large tooth size and overbite that Ceratasaur had.....

Just by looking at the skulls of Allosaur and Ceratasaur one notices the comparitivly huge size of Ceratasaur teeth. - Those alone would have inflicted harmful wounds by the sheer dimensions of them, without the need to resort to venom.

But I do disagree with Bakker here. I'm not so certain that Ceratasaur hunted hard shelled turtles. Not with delph like that.....
My guess was that Ceratasaur rather than Allosaur wuold be a better candidate for hunting like Smilodon..

Alvin T. Grey

steddyeddy wrote: »

That theory wasnt discounted it was the saliva theory that was superceded by the venom theory. They do have venom and venom ducts thats proven. Komodo bites can take several weeks to kill large animals such as deer and pymgy elelphants (extinct) but it is now thought to be the venom that ultimatly finished them off. The bite is the primary cause of death for smaller animals. The toxic proteins found in komodo glands have the effects seen prior to death in large animals.

If so, then it is a purely defensive adaptation and not required for hunting.

Think about it. If an animal is hunting, it needs to eat now. It can ill afford to wait for weeks to get it's meal. Secondly in the interveining time, the chances of the prey animal getting taken by a rival (it's now deffinatly weakened) gets greater day by day. - Slow poison makes no sense in that scenario.

However in a defensive scenario it doesn't matter that the animal dies now, or tomorrow or next week. The dragon's main concern is either seeing off a rival or surviving itself.

Or maybe the truth is somewhere in the middle. Possibly the original Komodos did have venom, but thanks to being on an island and being the biggest and meanest thing there got rid of the need for that. - Hence evolution dropped it due to lack of interest.

Adam Khor

Alvin T. Grey wrote: »

Or maybe the truth is somewhere in the middle. Possibly the original Komodos did have venom, but thanks to being on an island and being the biggest and meanest thing there got rid of the need for that. - Hence evolution dropped it due to lack of interest.

If this was the case, then mainland monitor lizards should be venomous still.

Alvin T. Grey

Adam Khor wrote: »

If this was the case, then mainland monitor lizards should be venomous still.

Not necessarily. Depends what species the Komodo descended from. BTW don't you find it odd that the sheer size of the Kommodo goes against the trend for island dwarfism? You would expect to find the smaller species on the island, not the largest....

Rubecula

Predators will fill a niche. If there is a niche for a certain size/type of carnivore then that niche will get filled (in time) The Komodo is as big as it is because nature has allowed it to get that big.

Alvin T. Grey

Rubecula wrote: »

Predators will fill a niche. If there is a niche for a certain size/type of carnivore then that niche will get filled (in time) The Komodo is as big as it is because nature has allowed it to get that big.

Nature rather finds a balance. In the case of size, it usually means growing as big (and no more) than it needs to be. The simplle reason being that a bigger body requires more calories. On an island you are limited to the amount of calories that are avalable as it's by and large a closed system. Hence island dwarifism.

But I guess the Kommodo didn't get the memo....:p

Adam Khor

Alvin T. Grey wrote: »

Nature rather finds a balance. In the case of size, it usually means growing as big (and no more) than it needs to be. The simplle reason being that a bigger body requires more calories. On an island you are limited to the amount of calories that are avalable as it's by and large a closed system. Hence island dwarifism.

But I guess the Kommodo didn't get the memo....:p

According to scientists, Komodos got that big (or remained that big, if they were already large when they arrived to the islands) due to the presence of pygmy elephants and other large mammals that were abundant during the Pleistocene in the Komodo archipielago. Since the islands were close to each other and the dragons could swim between them, they could move constantly in search for food and thus they didn´t wipe out their prey. There's also the fact that they are cold blooded and although they can eat incredible amounts of meat in each meal (80% of their body weight!), they can go without food for a long time (up to a month and a half).

Deer and buffalo were seemingly introduced to Komodo by humans, but after the extinction of the pygmy elephant, they became a good enough replacement in the Komodo's menu. So they never had the need to go smaller. They could survive, thanks to their being cold blooded, in a limited habitat with limited prey.

Galvasean

Good thread. Not sure I can bring myself to agree with the venomous Ceratosaurus idea, but I like seeing the forum used for such things, ie: bringing about ideas.

steddyeddy

As regards the Komodo dragon wheter it had venom and wheter it used venom to kill are two seperate issues. The dragons certanly have venom ducts and indeed toxic protiens were found in these ducts so they did have venom.

As regards how they kill, well that depends on the prey. Dragons use their claws and teeth to kill prey which they are capable of bringing down on their own. When they attack larger prey like the stegadon, buffalo, or the recently discovered flores man whom they shared an island with their behaviour changed. When attacking a larger animal the dragons have been seen to bite their prey a few times without the use of their claws, the drawing of blood then attracts other dragons. Often the dragons cease to attack for a while but follow their prey around over the following weeks. All this time the wound which the dragon inflicted does not heal and the creature gets weaker and weaker. As death aproachs the dragons home in and either finish the job or wait for the creature to die.

The fact that the larger prey of the dragons wounds do not heal certainly indicate the presence and action of at least some type of pathogen. This might seem a long drawn out way to kill prey but bear in mind that dragons have a very slow metabolisim and only need to feed once a month.

It strikes me that the medium sized dinosuars when attacking larger prey could indeed benifit from the use of venom. Maybe we can even estimate some of the dinsosaurs feeding and hunting habits from such a creature?

Alvin T. Grey

It just doesn't gel with the basic laws of predation. We know that preditors live by the basic equasions of calories in Vs calories out and risk Vs rewards.
So why expend the effort (calories out) of attacking an animal (and thus incurring risk of injury) to have it limp away just to be eaten by another dragon? or die in an inaccessable place after weeks of tracking it....

It just doesn't add up.

However it may be a case of inefficient hunting. Which of course doesn't matter if the prey items are plentiful, I'll agree with that. But as a survival method, it's pants.

And the second thing that I have an issue with is the type of 'venom'. It's woefully inefficiant. Each venomous creature uses it to quickly incapicitate. It lessens the chance of injury to the creature, it lessens the chance that the prey item can get beyond the creatures reach, and that it can be quickly recovered and eaten.

Which brings us back to the point that the presence of venom may be vestigal - or may be an emerging trait.

BlitzKrieg

I know the fossil record goes against this (with the number of caretosarus being found less then other predators)

But when you have long teeth, a horn and dermal armour down its back. This sounds like an animal who brawls and one that brawls in a group. I'd almost expect that they would hunt in pairs or packs and essentially try to kick the sh*t out of its prey as quickly as possible (large teeth used for pulling the prey while the other headbutts it over) I mean the quicker a larger prey is grounded the easier it is for them to essentially stamp the creature to death.

Again like the OP no experiance or qaulifications, just an observation.

Alvin T. Grey

I think it's one of those cases where looks can be decieving.

The horn on a C.saur was very slim and delicate, it wasn't the huge raming equipment of a ceretopsian for example nor was the other bits of the animal designed to be used in that way. The neck for instance wasn't particularly well reinforced.

The teeth also don't look like the kind that one would associate with a brawler like Allosaurus. They are fairly thin and fragile looking. The teeth could be best described as less than a cutlass and more of a scalpel. In that they were suitably sharp and strong when piercing or pulling backwards, but not so much when the prey tried to exit the mouth sideways.

steddyeddy

Alvin T. Grey wrote: »

It just doesn't gel with the basic laws of predation. We know that preditors live by the basic equasions of calories in Vs calories out and risk Vs rewards.
So why expend the effort (calories out) of attacking an animal (and thus incurring risk of injury) to have it limp away just to be eaten by another dragon? or die in an inaccessable place after weeks of tracking it....

It just doesn't add up.

However it may be a case of inefficient hunting. Which of course doesn't matter if the prey items are plentiful, I'll agree with that. But as a survival method, it's pants.

And the second thing that I have an issue with is the type of 'venom'. It's woefully inefficiant. Each venomous creature uses it to quickly incapicitate. It lessens the chance of injury to the creature, it lessens the chance that the prey item can get beyond the creatures reach, and that it can be quickly recovered and eaten.

Which brings us back to the point that the presence of venom may be vestigal - or may be an emerging trait.

It isnt an ideal hunting method but hey their still around so if it aint broke dont fix it! Not all venoms are fast acting and the fact that if a a komodo dragon attacks a bigger animal they bite once or twice, enough to inflict a flesh wound and then back off choosing to follow the animal instead of putting themselves in danger.

Galvasean

Plus a large kill like a buffalo can feed several komodo dragons so they don't really have to worry too much about someone else stealing their kill.

steddyeddy

Galvasean wrote: »

Plus a large kill like a buffalo can feed several komodo dragons so they don't really have to worry too much about someone else stealing their kill.

Yes exactly and for a reptile with a slow metabolic rate the meal will last much longer. I wonder from this could we postulate that some of the dinosaurs had a simular metabolic rate?

Alvin T. Grey

steddyeddy wrote: »

It isnt an ideal hunting method but hey their still around so if it aint broke dont fix it! Not all venoms are fast acting and the fact that if a a komodo dragon attacks a bigger animal they bite once or twice, enough to inflict a flesh wound and then back off choosing to follow the animal instead of putting themselves in danger.

They aren't fast acting on us. - But then again we aren't the usual prey species. In reptiles it usually works in seconds on the prey animal. The problem also with the bite and wait theory is that the wound may not be leathal. and while you are inflicting it you are exposed to the hooves and horns. It's much more efficent to pick the moment and inflict a wound that assures a meal. - Like lions, hyenas, falcons, spiders, crocodiles, sharks, just about everything else.

Hence my confusion.

The normal way that preditor/prey interactions work out is that the agressor overwhelms the victim either singely or in groups. It's basically a mugging where the odds are firmly stacked on the side of the preditor.

Galvasean

steddyeddy wrote: »

Yes exactly and for a reptile with a slow metabolic rate the meal will last much longer. I wonder from this could we postulate that some of the dinosaurs had a simular metabolic rate?

Every ounce of evidence gathered so far leans strongly against cold bloodedness in dinosaurs.

Alvin T. Grey wrote: »

The problem also with the bite and wait theory is that the wound may not be leathal. and while you are inflicting it you are exposed to the hooves and horns. It's much more efficent to pick the moment and inflict a wound that assures a meal. - Like lions, hyenas, falcons, spiders, crocodiles, sharks, just about everything else.

Komodo dragons do not have the tenacity for such attacks. To go for a killing blow would expose them to said hooves and horns. It would be more trouble than it's worth. Their nip and retreat hunting style has proved very effective. To say their method is not efficient is simply incorrect. It is very effective given the niche that komodo dragons occupy.
There's more than one way to skin a cat...

steddyeddy

Galvasean wrote: »

Every ounce of evidence gathered so far leans strongly against cold bloodedness in dinosaurs.

Im sorry excuse my ignorance my area is zoology I havent a clue about dinosaurs and most animals before the pleistocene but this forum is fostering an interest in me. I have to say that comes as a surprise that dinosaurs werent cold blooded so we can pretty much bet on a faster than komodo dragon metabolisim!



[/QUOTE]Komodo dragons do not have the tenacity for such attacks. To go for a killing blow would expose them to said hooves and horns. It would be more trouble than it's worth. Their nip and retreat hunting style has proved very effective. To say their method is not efficient is simply incorrect. It is very effective given the niche that komodo dragons occupy.
There's more than one way to skin a cat...[/QUOTE]

Thats it exactly its their bite and wait strategy that keeps them out of danger!

Adam Khor

Alvin T. Grey wrote: »

They aren't fast acting on us. - But then again we aren't the usual prey species. In reptiles it usually works in seconds on the prey animal. The problem also with the bite and wait theory is that the wound may not be leathal. and while you are inflicting it you are exposed to the hooves and horns. It's much more efficent to pick the moment and inflict a wound that assures a meal. - Like lions, hyenas, falcons, spiders, crocodiles, sharks, just about everything else.

Hence my confusion.

The normal way that preditor/prey interactions work out is that the agressor overwhelms the victim either singely or in groups. It's basically a mugging where the odds are firmly stacked on the side of the preditor.

The thing here is that the conditions in which Komodo dragons live are not what we would call "normal". First of all, they are the top predators in the islands, with no serious competitors. They don´t need to be utterly efficient because they aren´t competing with any other animals. They basically own the island and being cold blooded, they can take their time and wait for prey to die. No big deal. They will even start feeding on a live animal once it's too weak to run away. If the islands were home to warm blooded predators- say leopards or tigers- then yes, the dragons would be in huge disadvantage, and probably would either be scavengers or extinct.

But there's another important thing to consider. Water buffalo, wild boar, macaque and deer are NOT native to the islands. They were introduced by humans. The original Komodo dragon prey species were much smaller- giant rats, birds, and perhaps Homo floresiensis, as well as the pygmy elephant which would probably be the largest mammal in the Komodo's original range.
I would assume that Komodos fed mainly on the smaller animals, and they would be quite efficient killing them and eating them on the spot- the same way they will kill and eat macaques in one single attack today. There have been recorded cases of Komodos actually capturing macaques and swallowing them alive.
Stegodons were probably a special case- as the largest prey animal in the islands they would probably be hunted only rarely and using the same technique the dragons use today with larger animals. But this wouldn´t be extraordinary, because in today's ecosystems, the largest prey animals are only seldom targeted by the top predators (for example, lions and elephants, tigers and elephants, orcas and large whales) and the attacks are not always succesful.

And yes, probably Komodos are either descendants of a more venomous species, or are becoming more venomous themselves because now they feed mostly on animals larger than themselves. They would not be a freaky experiment of nature or an inusual, inefficient result of chance, but rather a quick-adapting, versatile predator that is still evolving and taking advantage of a changing environment.

Galvasean

steddyeddy wrote: »

Im sorry excuse my ignorance my area is zoology I havent a clue about dinosaurs and most animals before the pleistocene but this forum is fostering an interest in me. I have to say that comes as a surprise that dinosaurs werent cold blooded so we can pretty much bet on a faster than komodo dragon metabolisim!

Yeah, turns out even giant sauropods were warm blooded. I always assumed they would have been cold blooded. It now seems that the orthodox idea is that all dinosaurs were warm bloods (until new evidence can prove otherwise).