Scientists debate how male dinosaurs parented

Monday, December 29, 2008 | 6:00 p.m. CST; updated 6:16 p.m. CST, Monday, December 29, 2008

In a December issue of Science magazine, five brains from various fields came together to assert that some daddy dinosaurs might have been homemakers: Fossilized remains of male dinosaurs found sitting on eggs suggest that three species of ancient papas stayed at home with the nest while their female consorts went out foraging.

The relevance, many scientists have said, is that ancient dino paternal care could be the origin of paternal care in modern birds. Males help raise the baby birds in more than 90 percent of extant avian species, compared to less than 5 percent in extant mammalian species, making that practice one of the bird class’s defining features. Essentially, if the connection these scientists propose proves true, it could explain why an entire faction of animals parents the way it does.

The assertions of these five scientists are not as yet being treated as fact; a debate goes on about the origin of paternal care in birds as well as whether the bones found fossilized with the dinosaur eggs were indeed male. After hearing the news, I had a lengthy discussion with James Fox, a friend of mine, who teaches biology at Winchester College, and he seemed to think that daddy dino care made a lot of sense for a variety of reasons.

My first reaction was a resounding “Hurrah!” for early equal opportunity. But Mr. Fox explained that if male dinosaurs did in fact guard the eggs, their child-rearing likely did not mean that female liberation predated Susan B. Anthony by a few more million years than was previously thought (though I maintain that she would have insisted on sharing incubating responsibilities with her male partner). The reality, Mr. Fox said, is likely more to do with selfishness than gender equality.

In his book, "The Selfish Gene," Richard Dawkins explains this point, saying that if females forced males to do something that cost time or energy and which gave the males no direct benefit, all the females would be doing is inspiring the males to desert them and find some lower maintenance partners. A male would likely not, therefore, guard an egg nest just to benefit his mate, but he would do it to gain a great benefit for himself: namely, increasing the chances that his genes were passed on — an act all animals innately desire to accomplish.  

The ostrich, a relative of dinosaurs, provides a modern analogy that helps to exemplify this theory. The link between those three species of dinosaurs and that bird is a natural one to make, ostriches being animals which paternally incubate and which are flightless (as most dinosaurs were).

Flightless birds have an especial motivation to set males guarding the eggs, as they must account for all the predators making their way along the ground. An African ostrich must shield its progeny from lions, leopards, cheetahs and hyenas, as well as smaller carnivorous animals that may sneak up to the nest. The hen guards the nest during the day, but the male takes over at night when the threat from many predators is at its highest. Dinosaurs were similarly surrounded by toothy, meat-eating creatures and having the male guard the eggs could have been the most effective way of ensuring the young’s survival.        

Another term that gets thrown around by scientists examining parenting habits is “clutch,” which refers to the number of eggs in a nest. The five scientists found that the dinosaurs with the largest number of eggs were more likely to favor the paternal care model.

This is because animal actions are all about cost and benefit, Mr. Fox told me, and the benefit every male is constantly looking for, as we have said, is passing on his genes. If there were many eggs in the nest, the male would have a greater interest in spending his time looking after them, as many baby dinos might be the eventual reward. If there were only a few eggs, he would likely get more baby dinos by spending his time copulating with any willing dino-ess he could find.

It’s fascinating to consider how families may have been structured millions of years ago and to imagine what effect that might have had on modern mamas and papas. I only wish that those five scientists had given me, as those lucky birds, a reason to assert that the parenting prowess of my species is truly dinosauric.

Katy Steinmetz is a columnist and reporter for the Missourian. She moved to Columbia after spending two years teaching in Winchester, England, and one year in Edinburgh, Scotland. She has freelanced for a variety of publications, including 417 Magazine in Springfield, Mo., and the Guardian in London. Katy plans to complete her master's degree in 2010.

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