Oviraptor Ruminations II

The Oviraptor Strikes Back

From: Stan Friesen [swf@ElSegundoCA.ATTGIS.COM]

From: "Dan Lipkowitz" [lipkowit@midway.uchicago.edu]
> I was a bit surprised, however, to note that the eggs were of a size
> and quantity which seemed (to my eye) to comprise a larger total
> volume than the Oviraptor's body cavity. Unless the animal were
> walking around with a grotesquely distended abdomen prior to laying
> the eggs ..., I just can't see how it could have produced the entire
> clutch at one time. I suppose that it's possible that the eggs were
> dropped over an extended period of time (is there any history of this
> in modern animals?)

This is indeed quite common in living birds! Many birds lay one egg at a time, over a period of up to a couple weeks (depending on laying interval, clutch size, and time before hatching). Some birds do not even commence incubating the eggs until all are laid.

In fact, as near as I can tell, chickens do this. As I remember my grandfathers chickens, they each laid one egg at a time, with an interval of about one or two days. By collecting the eggs each day, the clutch never "filled up", so the hens kept right on laying new eggs.

As far as I can tell, this sort of system is more common in birds than is laying all eggs at one time.

Conclusion: it is both possible and likely that Oviraptor laid eggs one at a time over several days or weeks.

From: GSP1954@aol.com

Among modern large ratites, usually more than one female pays eggs in a single nest, which is then often brooded by a male.

From: "Dan Lipkowitz" [lipkowit@midway.uchicago.edu]

Of course, the many people who pointed out that depositing a clutch over an extended period of time is characteristic avian behavior are quite correct, and I'm ashamed that it slipped my mind at the time of my posting. In my own sad defense, I'd like to point out that the find at least calls into question the "egg-laying dance" which Jack Horner and Betty Quinn put on a few years back (I think it was Jack and BQ, at any rate), which demonstrates dropping of all the eggs in a clutch at the same time. Then again, they weren't trying to demonstrate maniraptor behavior (and it was darned amusing to watch, at any rate).

An interesting aspect of the specimen which I don't believe has been discussed so far (I'm not certain whether it was written up in the articles I read, but it was labeled on the mounted display) is that there is a thickening of bone on one of the arms (the right ulna, I think, though I won't swear to it) where the limb was broken and healed. Not a particularly rare discovery, but worthy of mention.

In a message dated 96-01-03 20:54:03 EST, NJusa@aol.com writes:

>Who's to say the Oviraptor wasn't feeding from another's nest?

From: ornstn@inforamp.net (Ronald Orenstein)

Highly unlikely, if its posture is any guide. The fossil is not just at the nest; it is sitting crouched over it with its arms wrapped protectively round the eggs. The posture is so similar to that of a brooding bird that it would be a remarkable coincidence if it were, in fact, predating the eggs instead.

From: Dinogeorge@aol.com

That's one small hole in the "brooding Oviraptor" concept. We know the eggs are Oviraptor eggs because other, identical, eggs contain identifiable Oviraptor embryos. That's how the idea they were Protoceratops eggs was discredited.

I like the idea of Protoceratops feeding on Oviraptor eggs.

Oviraptor might yet be branded an egg-eater. Its jaws contain two weird palatal "teeth" that might have evolved for the purpose of puncturing eggs, like the throat tooth of the egg-eating snake Dasypeltis.