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Re: gigantism as liability
----- Original Message -----
From: "Graydon" <firstname.lastname@example.org>
Consider sea-turtles; no parental care, young born very small and having
to spring down the beach to the water. Most don't make it, and must then
get through many years in the ocean to reach breeding size. Yet, absent
humans, turtles do very well.
Perhaps the essential thing was staying alive as an adult long enough to
lay enough eggs. That would make predator defence through size a
component of the r-strategy.
But turtles have additional predator defences: a tough shell...meaning that
increasing thickness of shell led to decreasing number of potential
predators. Rather than enjoying such incremental predator-immunity, each
cohort of sauropods would be greeted by a new guild of predators. Turtles
have a defensive strategy; I'm only arguing that sauropods must have had one
Because being really big means really strong reproductive constraints if
you're a mammal. One offspring every five years is not robust over
Is there actually a constraint on producing 5 smaller babies?
Sauropod nest defence has to explain how it could happen; 2 kg verses 20
tons is four orders of magnitude size difference.
Not sure what you mean here...
There's _three_ orders of magnitude between the adult and the probable
predators; how well would you expect rhinos to do, guarding against
There are plenty of examples of small predators picking on large...mice on
albatross, armadillos on rhea, black-backed jackal on ostrich, monitor
lizards on Nile crocs.