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Re: "Cursoriality", etc.
> >>Instead, a number of past giants show signs of running ability similar
> >>that of rhinos and big ground birds.
> I thought the largest ground birds like Moas and the earlier Dinornis had
> very thick legs with heavy bones. They seem better adapted to walking and
> standing which places the strain on compression more than flexion like
> running. It seems these animals weren't really capable of great speed
> like modern ostriches and Emus.
> Please correct me if I'm wrong.
A lot of these mega-birds (did I just invent a buzzword?)
lived on large islands (Moas, Elephant birds) which are devoid
of most large carnivores. Moas did have to contend with the largest
eagle ever known (apparently capable of taking down humans, which
may have contributed to their extinction), yet I doubt that running
would have particulary helped in avoiding something that drops from
the sky. Perhaps the robust build of the larger flightless birds
is a similar case to that of elephants: a lack of large terrestrial
predators to provide selective pressure.
There were several large birds on the Australian continent
(genyornis comes to mind), yet I don't think they were quite as robust
as some of the moa species. They had to contend with marsupial lions,
thylacines, megalania, and eventually humans. The thylacine was known
to be an endurance predator. I'm not sure that there was anything as
large as a moa or elephant bird in Australia.