[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: WHEN CASSOWARIES ATTACK



On Sun, 19 Aug 2001, Dann Pigdon wrote:

> Plus, forests were once home to several species of the Thylacaleo
> family. Emus were probably less prone to predation by them given their
> more open habitat. And as far as the dog killing reflex goes, perhaps
> Thylacines were the original targets.

As you know, the cassowary is the largest bird forest-dweller there is.
Comparing this habitat to that of the ostrich for a minute: ostriches use
concealment to prevent nest depredations--but they nest in areas of low
predator density (fewer sets of eyes/noses to find them).  If found by
jackals (Thylacine analogues) they can fight them off in the day
time.  But, at night, the jackals easily drive the birds off their nests
and eat the entire nest contents.
Theoretically there is going to be more predators in a forest (more
rainfall, vegetational productivity, more vertebrates to hunt).  Greater
predator density means the cassowary ought to be found.  Can the Thylacine
exploit the nest?
Unlike the jackals, Thylacines were not pack animals (right?)--this works
for the
cassowary, only having to deal with one at a time.  Were they
nocturnal?  We would know this for Tas Tiger, at least.
Isn't it possible that the evolution of a fierce claw and a nasty attitude
could have saved the day for many a cassowary nest, whereas the same
traits in an ostrich would have not much value.
As for emus, as far as I know the male lays in torpor on his nest.  Out in
the arid stretches of the grassland, its only hope may have been to lay as
still as possible and hope the big bad _Megalania_ doesn't see it!