Sauropod musings

["Norton, Patrick" <Patrick.Norton@state.me.us>]

Virginia Tidwell wrote:

<This question has bothered me for quite some time.  Any new ideas would   
be
most welcome on the subject.>

Ecologists have developed and applied the concepts of optimal foraging   
theory to contemporary large vegetarian browsers (ungulates) for nearly   
30 years. Those studies have found that factors such as body size, diet   
and habitat are correlated to herding tendencies and herd structure.

I'm not aware of many dinosaur researchers who have drawn from that body   
of knowledge, but it may offer some promise. Peter Dodson, for example   
speculated (in Dinosauria) that Sauropods may have possessed hindgut   
fermentation. Although he didn't expound upon it, his speculation is   
based upon the known physiological differences among living large   
herbivorous browsers and could, in my opinion, be viewed as a prediction   
based upon optimal foraging theory. It's long been known that bacterial   
fermentation in the foregut of ruminent arteriodactyls (cows, for   
example) give them an advantage over other ungulates in areas of limited   
high quality forage.  But Perrissodactyls (horses, for example) and   
subungulates (such as elephants) have the advantage in areas containing   
large amounts of low quality quality food.  Their hindgut fermention (in   
the cecum and colon) is less efficient at utilizing cellulose, but they   
can process food faster than ruminents and are able to extract certain   
nutrients from forage before fermentation occurs, which ruminents can not   
do.

If one were willing, one could speculate even further. For example, there   
are distinct differences in herding tendencies and herd composition among   
today's arteriodactyls and perissodactyls. For example, only the smallest   
ungulates forage alone. All larger ungulates (except for Moose, as far as   
I know) show some type of herding behavior. Arteriodactyls usually occur   
in either fixed herds, which are usually permanent and consist mostly of   
related individuals, or in more temporary herds, which are usually formed   
during migrations.  Perissodactyl and subungulate herds are usually more   
like a harem--a male with a number of females and offspring.  These   
different types of herding behaviors also exhibit distinctly different   
degrees of size differentiation between males and females and differing   
degrees of display characteristics, such as horns.

Behavior doesn't fossilize, but size differences and display   
characteristics usually do. With what we already know about sauropod   
anatomy, diet and paleohabitat--combined with information from   
trackways--it seems that contemporary foraging theories and observations   
of living large herbivores could be the basis for some further hypotheses   
about herding behavior and herd composition among sauropods.

Pat Norton