From National Geographic News (spotted by our own Matthew Cobb) comes this amazing discovery: a nest of 15 babies of a dinosaur related to Triceratops. The nest, about 75 million years old contains juvenile Protoceratops andrewsi, and was found in Mongolia. Here’s the parent:
This is a small dinosaur, about 1.5-2 meters long as an adult and weighing roughly 400 pounds. It has the characteristic neck frill of the group, a feature whose function is unknown. Wikipedia suggests the trait could have been for protection from predators (this species was herbivorous), to anchor neck muscles, or to “impress other members of the species” (I presume this is sexual selection, but in that case the neck frill would be larger in males and one should see sexual dimorphism in fossil adults), or a combination of these.
The high concentration of individuals in some areas has suggested that they might have lived in herds.
And the nest, which is 0.7 m (2.3 feet) wide:
The presence of all these babies together suggests to one of the discoverers, David Fastovsky, that there was parental care. Since these aren’t newborns—they’re estimated at about a year old—I can’t imagine what other explanation there could be, unless baby dinos stayed together in the nest without parents for a year.
All the babies are facing the same way, suggesting to Fastovsky that they died in a sandstorm, facing away from the wind. If that was the case, they could have been covered by an encroaching dune.
And a beaked baby:
National Geographic adds:
Another fossil discovered in the same region shows an adult Protoceratops and a velociraptor locked in an apparent death grip. “So you have two stunning examples of dinosaur behavior frozen for us to see some 75 million years later,” Fastovsky said.
It’s likely that velociraptors preyed on Protoceratops young, he added: “The desert environment where they lived just had to be hard, and possibly there were relatively high mortality rates.”
I’m no paleontologist, and the people who discovered these are, but I’m still curious how herds of large herbivores could have survived in the desert, and whether the area might have been more lush than the article portrays.
There’s plenty of modern herd animals that are able to survive in deserts: desert bighorn sheep, oryx, Bactrian camels, and even elephants.
Also, subscribing.
They all display nomadic behaviour in the desert, however. The dinosaurs obviously weren’t nomadic, having reared their young in the same place for a year. Of course, they may have relocated and built a new nest, but it seems improbable.
“Lush” is rather relative. The key thing here is that grass was not widespread until long after these dinos died. That’s not to say there was not ample plant life, but grass serves a key structural role in holding down sediment. Without a sprawling carpet of grass with it’s roots to stop sand from blowing, even regions with otherwise ample plant life for dinosaur-suppprt would have the potential for large, migrating dunes.
I do love these discoveries but sometimes the scenarios they depict make me very, very sad. Poor baby dinosaurs caught in a sandstorm.
This is why I can’t be a scientist.
For a different (?) viewpoint, here is Brian Switek’s article:
“What this discovery indicates about parental care in Protoceratops is uncertain. No adult dinosaur was found in association with the babies. Perhaps the adult continued to care for the little dinosaurs while they remained in the nest, or perhaps they left the nest and the baby dinosaurs remained together in the nest area. With any luck, future discoveries will provide more insight into these points. Nevertheless, the new find adds to the growing body of evidence that many dinosaurs stuck together as juveniles.”
Re the desert: Maybe they ate sagebrush and tumbleweeds. I’m only being partially facetious.
I live in the high desert are of Washington State (yeah, we call it the desert). It is a semi-arid steppe much like what I suspect the area in question was. We even have scrub oak, and amounts of vegetation depends on whether we have more or less than our average 6 inches of rain each year. We even have a sand dune to the north of town that has been visibly moving eastward with the prevailing winds in the past decades.
Most people don’t realize that a huge amount of Washington State is like this. You don’t get the sickening green lushness until you get west past the Cascades and the constant rain. Give me the desert any day.
(I used the word “sickening” as a bit of inside joke. When I first came here years ago for my interviews I was waiting in the airport lobby for the company rep. A woman nearby was on the phone explaining to a friend that she had been in Norway working at another research lab for a year. What I remember is her comment that “I am so happy to be back where you can see past the next tree. The green is almost sickening in its consistency.”
Here is a great 15 minute tour:
Damn! Sorry I embedded the video rather than just the link. I know that when the link says “embedded” in it you have to manipulate it.
The landscape you describe is a thoroughly modern one. You have to remember that flowering plants (a group that includes the vast majority of plants we are familiar with, including each one you mentioned) were not fully exploiting environmental niches during this period.
Prolonged parental care is hardly unique in the animal kingdom; ostriches. Lion prides and even cephalopods all have this evolutionary survival strategy. It could also have been a social rearing of the young a la the naked mole rats, this would make sense if resources where scarce and there were predators about. The fact that the young where located in the nest at least suggests parental feeding/care of the young.
I think the term nest is misleading
How is parental feeding of the young possible in dinosaur herbivores? Their diet isn’t energy-rich enough to make it worthwhile bringing anything back to the nest other than nuts or fruit ~ that isn’t practical for 15 large chicks. AFAIK there isn’t a dinosaur equivalent of milk & a herbivore can’t very well turn up at the nest with a protein-rich carcass to feed the one year old dinosaur chicks.
I believe that the dead chicks are not all siblings & they are together because it’s easier to protect them if you ‘circle the wagons’ (the adults) around a huddle of the young. Perhaps at night & in storms it’s the practise to run a convoy protection system with the high value & vulnerable young placed in the middle of the herd. Actually this protection system must run all the time.
The real puzzle for me is how an egg-laying HERD can stay in one place long enough to hatch the eggs. I assume that all (or a portion of) the herd must remain rooted to an area for a number of weeks & eat the area back to nothing
I looked up ostrich behaviour & perhaps we can see some answers in their behaviour ~ they normally spend the winter months in pairs or alone. During breeding season and sometimes during extreme rainless periods they live in nomadic groups of five to 50 birds (led by a top hen) that often travel together with other grazing animals, such as zebras or antelopes. Wiki :-
Excellent point about nesting and also being herbivores, though I’m still finding it problematic when it comes to herding. Even as I commented on the ostriches I was still a bit wary due to the short parental care issue though it is long in nature. I wonder if they where omnivores who later adapted to eating green?
Green iguanas, which are largely herbivorous as adults, eat much more animal food when young– lots of protein for rapid growth. But adults bringing food they don’t eat themselves might be unusual. Also, crocodilians care for their young in groups, but don’t (at least in general) feed them. The young are localized, but not in a constructed nest. (The eggs are laid in a nest, but the hatchlings leave this and don’t return.)
“How is parental feeding of the young possible in dinosaur herbivores? Their diet isn’t energy-rich enough to make it worthwhile bringing anything back to the nest other than nuts or fruit ~ that isn’t practical for 15 large chicks. AFAIK there isn’t a dinosaur equivalent of milk & a herbivore can’t very well turn up at the nest with a protein-rich carcass to feed the one year old dinosaur chicks.”
Maybe, like Maiasaura & most birds, adult Protoceratops fed their young regurgitated food.
It’s interesting that your first picture (of the adult Protoceratops at the Carnegie Museum)also shows a nest, but one filled with eggs. That nest, however, is clearly an Oviraptor nest. Presumably, when that display was mounted it was still thought that the eggs belonged to Protoceratops, which is why the poor mother theropod got that libelous name just for sitting on her own nest.
And whether you expect sexual dimorphism in a trait subject to sexual selection depends on the relative parental investement of the two sexes. If it’s high for both sexes, we would expect similar traits, as found in many passerine birds, for example. Some bird species even have showy females and drab males because of increased male and reduced female investment.
Regarding dinosaure food, I was surprised to learn that so many dinosaurs ate evergreen trees, more so than today’s fauna does. Ain’t evolution wonderful that it enables animals to change their diets to accommodate to changing environments.
The function of the “frill” of the ceratopsians is still simply unclear. The possibility that there is significant sexual dimorphism in this clade has been discussed in the trade for a long time. I’m pretty sure that it was discussed in several parts of Dodson’s “The Horned Dinosaurs” (ISBN 0691028826, 1996 – surely it’s not that old, or am I needing to get my Zimmer frame re-sprayed?) ; it may have been mentioned in Bakker’s more hysterical moments in the mid-70s ; it has certainly been more formally discussed in respect of IIRC one of the Torosauridae genera in the last few months.
At worst, half of all ceratopsian clades might be redesignated as junior synonyms for “the other” gender. That wouldn’t be devastating – there are a *lot* of ceratopsians (parts of Dodson’s generally excellent book cited above got a bit boring, and it’s 15 years out of date).
More likely, if there is dimorphism, some existing clades will be merged, but some clades we’ll only have the male morphotype, some we’ll only have the female morphotype, and some will have indistinguishable morphotypes in the hard parts.
I wouldn’t put *your* money (up to the price of a beer) on a bet as to whether any particular “large frill” were from a male, a female, or a particularly butch female.
Oh, hang on … given that birds don’t have 2-chromosome sexual genetics, but something more complex … the number of complicating possibilities gets much bigger. I think I’ll keep my money invested as beer, and would advise you to do the same.
@4 Torbjorn “Perhaps the adult continued to care for the little dinosaurs while they remained in the nest, or perhaps they left the nest and the baby dinosaurs remained together in the nest area. With any luck, future discoveries will provide more insight into these points.”
IIRC One of Jack Horner’s reports from Wyoming (?) is of a considerable number of single-style nests spread across a single flood plain, on an approximately hexagonal grid at a spacing comparable to the body length of the adult ; pretty good evidence that in one dinosaur clade, communal simultaneous nesting occurred. The behaviour isn’t proven to be general, but it is strongly indicated to be in the group’s repertoire of available behaviours.
see my comment #6 above re ostrich communal nests. Fits well.
Oh, hang on … given that birds don’t have 2-chromosome sexual genetics, but something more complex …
Not sure what you’re saying here, but birds have the same kind of 2-chromosome sexual genetics that mammals do, just that the females are the heterogametic ones: males are ZZ, females are ZW.
…Which explains Cuckoos you may recall from previous posts on WEIT…
?
How does chromosomal sex determination control sexual selection and sexual dimorphism?
The bright colours and elaborate structures of male flies, poeceliid fishes (guppies and mollies), various birds, antler- or horn-wearing mammals, crabs, etc. where they have been mapped to particular chromosomes do not map to sex chromosomes, these traits are most often autosomal. Linkage disequilibrium is what is required to for runaway sexual selection, not a particular sex determination system.
Small nitpick but when I read “Here’s the parent” I thought you meant that it was a picture of the parent of the babies found, as opposed to a picture of an adult of the same species. You might want to consider rephrasing it:
“Here’s an adult from the same species”
Of course it just might be because English is not my first language.
(subscribing)