Pack hunting dinosaurs

[Sharptooth]

Evidence for parental care in Maiasaura is not so "faint" as you put it 

Plus, many young animals today still stay with their parents even if, physically speakin', they could already live on their own... Ostrich chicks for example can catch food and walk on their own just after they hatch, yet (surprise, surprise!) they stay with their parents for quite a time; both the male and the female teach'em how to feed, how to evade predators and all the stuff they'll need once they'll go alone into the wild.

And i could list many more examples like this! It's not that, if an animal is already capable of walking and feeding just after his birth, it always  means he doesn't need his family 

[Arioch]

Evidence for parental care in Maiasaura is not so "faint" as you put it 

So scientists theories are 100% reliable this time? Watch the contradictions! Pretty much every evidence involving dinosaur social behaviour is pretty faint. And faint does not necessarily mean weak or inconsistent.

Plus, many young animals today still stay with their parents even if, physically speakin', they could already live on their own... Ostrich chicks for example can catch food and walk on their own just after they hatch, yet (surprise, surprise!) they stay with their parents for quite a time; both the male and the female teach'em how to feed, how to evade predators and all the stuff they'll need once they'll go alone into the wild.

Hardly a proof of most dinosaurs having extended parental care, especially with (again) stratigraphy and growth rates ( many years to reach the size of a sub adult) telling us otherwise. An ostrich becomes an adult in just 18 months.

[Gryphoceratops]

If I'm not mistaken I think at least hadrosaurs show evidence of growing very rapidly early on.  I remember seeing a hatchling femur compared to a yearling femur, the size difference was astonishing.  These are also the kinds of dinosaurs that show at least some evidence of parental care.  Also ceratopsids have been discovered in big bonebeds including both adults and babies so there could have been some sort of relationship between parents and their young there as well.  Also keep in mind that vertebrates that tend to be independent from birth often look like little miniature adults (lizards, snakes...).  The ones that care for their young start out looking more "baby-like".  Taking this into consideration ceratopsid babies have shorter frills and smaller or no horns.  Hadrosaur babies don't have their crests yet. 

Sauropods and ankylosaurs on the other hand I think are the ones that show the babies going off on their own right after hatching.  Which is also totally plausible. 

i think its safe to assume that since both crocodilians and birds care for their young in some form or another some (maybe not all) non avian dinosaurs did as well. 

[Sharptooth]

Ok, ok, i mistaken "faint" for "weak", my bad... But if you say, and i agree, that basically every evidence for dinosaur behavior is close to zero, why it looks like you're SO sure they didn't have parental care? 

And speakin' frankly, if some dinosaurs took so long to grow (14 years in the case of T.rex), well, i could see it as a sign that they stayed with their parents for a lil' longer than we usually believe... Maybe they had to learn all they need to survive, like it happens with many animals (especially predators) today?

[Metallisuchus]

I'm pretty sure fast metabolic rates are a strong piece of evidence for dinosaurs being endothermic. I don't know much about dinosaur growth rates though, admittedly.

EDIT: Fast metabolic rates = fast growth rates, typically. Correct?

[Arioch]

Sharptooth: Where did I say there couldn´t be parental care at all? the kind of extended parental care that birds practice is not the same of other archosaurs.

And frankly, an animal that did need 10 years to learn how to hunt or escape predators wouldn´t be very successful in a wild environment.

I noticed you like to slag off scientists and their "arrogance". See, theories are builded upon evidence + educated guesses based on phylogenetic bracketing and ontogenic studies, and none of them are 100% sure, that´s why they´re called theories. In paleontology, the most likely option is treated like a "fact" until proven otherwise with more solid data and a refuting theory. That´s how paleontology (and science) progresses. You can´t fight theories supported by the slightlest evidence with speculation supported by none, that´s bad science. And sadly there is no shortage of people doing it.

If I'm not mistaken I think at least hadrosaurs show evidence of growing very rapidly early on.  I remember seeing a hatchling femur compared to a yearling femur, the size difference was astonishing.  These are also the kinds of dinosaurs that show at least some evidence of parental care.  Also ceratopsids have been discovered in big bonebeds including both adults and babies so there could have been some sort of relationship between parents and their young there as well.  Also keep in mind that vertebrates that tend to be independent from birth often look like little miniature adults (lizards, snakes...).  The ones that care for their young start out looking more "baby-like".  Taking this into consideration ceratopsid babies have shorter frills and smaller or no horns.  Hadrosaur babies don't have their crests yet. 

Sauropods and ankylosaurs on the other hand I think are the ones that show the babies going off on their own right after hatching.  Which is also totally plausible. 

i think its safe to assume that since both crocodilians and birds care for their young in some form or another some (maybe not all) non avian dinosaurs did as well.

We even have tracks of sauropods that show adults and juvies moving along together. Other species show a more drastic niche partitioning and matures and young ones seem to have lived far from each other. Still, the former seem to be the exceptional exception within non avian dinosaurs, rather than the rule.

[Gwangi]

Because of phylogenetic bracketing I believe most dinosaurs displayed some level of parental care, just as most living archosaurs do today. I'm sure it varied between families. For example, the evidence is pretty good that sauropods did not care for their young (how could they really?) but I'm inclined to believe most theropods did. I'm sure some only invested a limited amount of care like crocodiles while others may have been more extensive like modern day birds with precocial young. Precocial chicks don't require too much in the way of care, they're born knowing nearly everything they need to. All they need to learn is where resources are located and of course they need protection from predators. The parents would serve more as supervisors than anything else. I doubt there were any altricial dinosaurs but if there is evidence of them someone please let me know.
As for tracks being found together, this only proves they moved around together. Just as with dromaeosaur tracks we can't know the level of involvement between individuals. It may have been good enough for young ceratopsians or hadrosaurs to simply follow adults around without any direct care.

[Gryphoceratops]

Yeah but you still can't explain the morphological differences between baby and adult cerapods.  There was more than likely some sort of parental care going on there.  The fact that they have been found together in groups just reinforces that. 

[Gwangi]

Yeah but you still can't explain the morphological differences between baby and adult cerapods.  There was more than likely some sort of parental care going on there.  The fact that they have been found together in groups just reinforces that.

Yeah...I said most dinosaurs probably invested some amount of parental care didn't I? Phylogenetic bracketing and all that...I'm certain I did. 

EDIT: But while were talking about morphological differences lets take a look at the Jackson chameleon.





Which just goes to show you that young animals can still look different from their parents and not be dependent on them. Things like horns and frills and crests if their primary purpose is sexual would have no use on juvenile animals so it makes sense that they would lack them. Especially to let older individuals know they aren't ready to participate in adult activities. All a baby triceratops without horns tells me is that it isn't sexually mature.

[Sharptooth]

Sharptooth: Where did I say there couldn´t be parental care at all? the kind of extended parental care that birds practice is not the same of other archosaurs.

Sorry, you made it sounds like that.

And frankly, an animal that did need 10 years to learn how to hunt or escape predators wouldn´t be very successful in a wild environment.

That's not always true, plus i didn't specifically say that (for example) a T.rex would have spent all of his 14 first years training... Heck, there are many reasons for a juvenile to stay with his parents; there's an african species of owls (Verraux owls) where, sometimes, the sub-adult goes away for a while and then return to help his parents raise the newborn chicks...

I noticed you like to slag off scientists and their "arrogance".

Yes, because even if the body of what we know about dinosaurs (and Prehistory in general) is mostly made of theories (which could be proven or not), some scientists act like they have the "Truth" (with a capital T, of course)... These guys (and there are many of 'em in basically every field) are indeed arrogant and promote a dogmatic view of science that sounds almost like a religion, and to make thing worse, there's an even greater number of common people who read their "truths" on the newspapers (or in a blog...) and believe blindly in 'em because, you know, they are THE experts afterall... These guys don't say "it could be" but "IT IS" and, sorry, but i don't consider it good science.

[DinoFan45]

I personally think that it was dependent on the dinosaur's size. A giant sauropod who needed to eat a lot in a day probably didn't care for its young as much as a troodon. The bigger the animal, the less it took care of young. An exception could possibly be theropods, as they could work in groups and bring food for young. It could also explains why some animals had healed injuries, such as broken ribs, which could inhibit their ability to hunt.

[Sharptooth]

I would not totally rule out the possibility that maybe some species of sauropods cared for their chicks... By the way, i just noticed that LO & BEHOLD, the "pack hunting dinosaurs" topic is (not so) slowly morphing into the "parental care in dinosaurs" topic instead, weeeeee!!!  *orthocone*   *orthocone*   

[Gwangi]

I would not totally rule out the possibility that maybe some species of sauropods cared for their chicks... By the way, i just noticed that LO & BEHOLD, the "pack hunting dinosaurs" topic is (not so) slowly morphing into the "parental care in dinosaurs" topic instead, weeeeee!!!  *orthocone*   *orthocone*   

We're gonna touch on all the controversies in this one. Bring it on!

The evidence shows that sauropods probably didn't care for their young so for now I'll assume none of them did...until convincing evidence shows otherwise.

[Metallisuchus]

Gwangi, what evidence shows that sauropods didn't care for their young? Considering how vulnerable they must have been at a young age, I can't possibly imagine their survival into adulthood without parental care.

The only defense I know of (which is theoretical) is the sea-turtle method - having such an abundance of a litter that they'd survive solely based on odds.

And there have been trackways providing footprints of both young and old of various herbivorous herds, including sauropods, traveling together in one direction.

I'm not saying you're wrong, I'm simply asking for what evidence you may know of, because it seems naturally illogical to me for sauropods to disregard their juveniles.

[Gwangi]

Gwangi, what evidence shows that sauropods didn't care for their young? Considering how vulnerable they must have been at a young age, I can't possibly imagine their survival into adulthood without parental care.

The only defense I know of (which is theoretical) is the sea-turtle method - having such an abundance of a litter that they'd survive solely based on odds.

And there have been trackways providing footprints of both young and old of various herbivorous herds, including sauropods, traveling together in one direction.

I'm not saying you're wrong, I'm simply asking for what evidence you may know of, because it seems naturally illogical to me for sauropods to disregard their juveniles.

There have been mixed age trackways found for some species of sauropods but there have also been trackways found where all the animals were of the same age, even juveniles. From what I know about sauropods it seems most laid their eggs in a manner similar to sea turtles with numerous individuals laying a lot of eggs in some sort of nesting ground. Sauropods if I'm not mistaken were among the fastest growing of animals so even though they were vulnerable upon hatching (like sea turtles and other reptiles) they quickly closed the gap with fast growth. Once they reached a certain size I don't think they had much to fear from anything so I think a sea turtle method of reproduction was most likely. There are even birds (or at least a bird) alive today that adopts the same method.
I believe the best evidence for a lack of parental care is the size of the adult animals. The eggs laid were small, smaller than the largest known bird egg even and so I doubt the parents would have an easy time keeping track of newly hatched young, most would probably get stepped on!
Also sauropods seem to be herding animals and I doubt they had the time or resources at hand to wait for the eggs to hatch. These animals needed a lot of food and probably had to keep moving in order to get it, they didn't have the time to stop and wait however many months it took the eggs to hatch. There is also the issue of what the babies were eating. Being so much smaller than their parents I imagine they must have exploited a different food source and so they may have went their separate ways. I believe a study was done at some point saying the structure of baby sauropod teeth was actually different than the adults which means they probably ate different things. Perhaps young animals ventured out on their own upon hatching only to join up with a herd later in life? No doubt simply being in the presence of adult animals may have offered some protection but I doubt they received any direct care and don't really see how they could have.

[Metallisuchus]

Gwangi, what evidence shows that sauropods didn't care for their young? Considering how vulnerable they must have been at a young age, I can't possibly imagine their survival into adulthood without parental care.

The only defense I know of (which is theoretical) is the sea-turtle method - having such an abundance of a litter that they'd survive solely based on odds.

And there have been trackways providing footprints of both young and old of various herbivorous herds, including sauropods, traveling together in one direction.

I'm not saying you're wrong, I'm simply asking for what evidence you may know of, because it seems naturally illogical to me for sauropods to disregard their juveniles.

There have been mixed age trackways found for some species of sauropods but there have also been trackways found where all the animals were of the same age, even juveniles. From what I know about sauropods it seems most laid their eggs in a manner similar to sea turtles with numerous individuals laying a lot of eggs in some sort of nesting ground. Sauropods if I'm not mistaken were among the fastest growing of animals so even though they were vulnerable upon hatching (like sea turtles and other reptiles) they quickly closed the gap with fast growth. Once they reached a certain size I don't think they had much to fear from anything so I think a sea turtle method of reproduction was most likely. There are even birds (or at least a bird) alive today that adopts the same method.
I believe the best evidence for a lack of parental care is the size of the adult animals. The eggs laid were small, smaller than the largest known bird egg even and so I doubt the parents would have an easy time keeping track of newly hatched young, most would probably get stepped on!
Also sauropods seem to be herding animals and I doubt they had the time or resources at hand to wait for the eggs to hatch. These animals needed a lot of food and probably had to keep moving in order to get it, they didn't have the time to stop and wait however many months it took the eggs to hatch. There is also the issue of what the babies were eating. Being so much smaller than their parents I imagine they must have exploited a different food source and so they may have went their separate ways. I believe a study was done at some point saying the structure of baby sauropod teeth was actually different than the adults which means they probably ate different things. Perhaps young animals ventured out on their own upon hatching only to join up with a herd later in life? No doubt simply being in the presence of adult animals may have offered some protection but I doubt they received any direct care and don't really see how they could have.

Interesting points, and yes I too have considered the fact that Sauropods likely had to keep moving and eating, but perhaps they could fast for some period? No matter how you look at it, there's seems to be a problem. There's got to be an explanation that none of us have theorized. What's that bird that lays it's eggs in other species' nests so that they're taken care of (or something of that nature)? Do you think that's even possible for a Brachiosaurus or Camarasaurus to have done?

Regarding dentation - that's usually the case for most warm-blooded animals though right? If parental care did exist, then there could be the regurgitating food method, or just different (softer) vegetation for youngsters. Crocs carry their young in their mouths as well...

And yes, I agree - being stepped on by community parents would be a big threat!

[Gryphoceratops]

Brown-headed Cowbirds and Cuckoos both exhibit this behavior.  I can't really imagine a sauropod doing the same though. 

[Sharptooth]

Yeah, a bigass sauropod using the same technique of cuckoos doesn't look quite right. 


Anyway, as i already said, in wouldn't rule out the possibility that some long necks cared for their young; one of the things i don't like in paleontology, is that sometimes people make assumptions on dinosaur beahvior just by lookin' at a single discovery and then generalize.
I'll be clearer: take for example the trackways mentioned by Gwangi, they show animals of the same age not travelling together, and many people guess it shows that sauropods didn't have parental care. But are we sure we can apply this behavior to ALL the sauropod family? Seriously, that's a big jump! All we can infer is, in that particular occasion, a herd of animals of the same age left their footsteps there, stop. And the same can be applied, on the opposite view, to Metallisuchus' example. Some 'pods maybe cared for their young (and those nesting grounds in South America could suggest something similar to hadrosaurs' habits), some maybe not, that's it!

[Dinoguy2]

Gwangi, what evidence shows that sauropods didn't care for their young? Considering how vulnerable they must have been at a young age, I can't possibly imagine their survival into adulthood without parental care.

Most didn't Sauropods laid a ton of eggs per nest. If most of those babies lived to adulthood, the ecosystem would have been utterly decimated within a single generation. All evidence says that sauropods bred like sea turtles: lay a ton off eggs, abandon the helpless young. Most of the young get eaten immediately by predators. The few that live escape by pure luck and the fact that the predators are swamped with too much food (i.e. they can't possibly eat ALL those babies). The one or two from each nest that live go on to produce tons more babies.

Once the survivors were relatively large, they would have started forming herds, or joining in with adult herds for protection. But there's no way a sauropod could care for its young babies, as they need to eat constantly and there's no possible physical way a juvenile sauropd could eat the same food as an adult, especially if they were browsers. Babies and adults filled different ecological niches.

[Sharptooth]

And again, here's what i call "generalizing" 

I'm not saying that the "turtle analogy" is wrong, but i would be less confident to apply this model to ALL the sauropods... Baby 'pods ate differently than their (much, much, much) bigger counterparts, ok, but this doesn't immediately lead to NO PARENTAL CARE AT ALL, at least it doesn't sounds quite right to me.