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Re: attack on dinosaur--horrific video
Andrew Simpson said:
The outer eggs in an ostrich clutch are false/duds and
will not produce young. Lions finding an ostrich nest
will destroy a few in their initial excited frenzy but
are then powerless to break open any more after that.
The valuable eggs are usually spared.
Unless you have another one (supply us w/refs)...Bertram is the best source
(refs if needed)
who says a major hen invites lesser hens to lay in her nest--because (he
believes) she has surplus incubation room and can accomodate more eggs w/out
additional expense. She then sequesters all her eggs closer to the middle
so that if there is marginal nest predation (lions perhaps) her eggs are
more likely to survive. This benefit also accrues to safety in numbers as
chicks. I haven't heard of the "false eggs" thing unless it applies to rhea
eggs who may lay decoy eggs outside the nest. Anyway, lions are not the
prime preds of o nests--this goes to black backed jackals which cause total
nest abandonment. Let us know if you know different. And--according to
Bertram--only one of every ten embryos ever see a first b'day!
Would dinosaurs have had false eggs? Super thick eggs
would seem valuable against smaller egg thieves but
couldn't create an egg a large carnosaur couldn't
crush and eat.
A still unexplored hypothesis is: dinosaurs were big in order to protect
against predation at the nest--i.e., protection was likely from direct
defense. So, I agree making thick shells would be pointless as protection
against big carnsoaurs. But it turns out that thick shells are not much
protection against small preds as well! Example is: rhea eggs are smashed
together by relatively small hairy armadillos.
I tend to think that dinosaurs ran the gambit when it
came to clutch protection.
I agree. However, the gambit is limited by--most of all--the necessity of
having to leave a valuable food resource in one location.