Wednesday, November 17, 2010

Puggles Part III



It's not uncommon these days to see paleo art depicting Mesozoic maniraptors feeding their young in the manner that many living maniraptors do now. But, in truth, this may not have been the case for most Mesozoic maniraptors.

Mesozoic maniraptors appear to have been most similar in reproductive habits to more basal modern birds such as palaeognaths, the tinamous and their flightless relatives such as ostriches and emus. Like many palaeognaths, male oviraptorosaurs and deinonychosaurs appear to have took multiple mates, who then laid their eggs in one big clutch. The males were probably the ones responsible for brooding the nests.

Also like palaeognaths (as well as basal neognaths such as the gallianseres - the pheasant and duck group), young oviraptorosaurs and deinonychosaurs could run and walk well as soon as they were out of the egg. As a result, they were probably quite capable of feeding themselves. One or both of their parents may have helped shelter them from predators and lead them to food sources, but when it came down to actually procuring the food, the hatchlings were most likely on their own.

So, unlike the blind and helpless young that early mammals probably had, theropods in general likely had very precocial young!

Now, it's still possible that these theropods fed their young on some occasions, as crocodiles (which are also archosaurs that have hatchlings which can hunt for themselves) have been observed feeding their young in captivity. But given the apparent rarity of this behavior, it's still safer to assume that most Mesozoic theropods didn't feed their young most of the time, if they did at all.

2 comments:

  1. "Like many palaeognaths, male oviraptorosaurs and deinonychosaurs appear to have took multiple mates, who then laid their eggs in one big clutch. The males were probably the ones responsible for brooding the nests."

    No offense, but that's WAY too broad a generalization. At most, you can say that about male oviraptorids & Troodon.

    "Also like palaeognaths (as well as basal neognaths such as the gallianseres - the pheasant and duck group), young oviraptorosaurs and deinonychosaurs could run and walk well as soon as they were out of the egg. As a result, they were probably quite capable of feeding themselves."

    Not necessarily. Grebes, rails, gulls, & terns feed their precocial 4/semi-precocial chicks (See "Precocial" & "Semi-precocial": http://www.stanford.edu/group/stanfordbirds/text/essays/Precocial_and_Altricial.html ). BTW, the only difference btwn precocial 4 chicks & semi-precocial chicks seems to be that the latter stay in/near the nest. Since that seems to have been the case for Troodon chicks (See the Gardom & Milner quote), 1 could argue that they too were semi-precocial.

    -JD-man

    Quoting Gardom & Milner ( http://www.amazon.com/gp/product/184442183X?tag=533643275-20 ): "The discovery of several half grown juvenile skeletons suggests that the hatchlings, although mobile, probably stayed near the nesting site for some while."

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