RE: Phorusrhacids killing large mammals in National Geographic Channel

[Dann Pigdon <dannj@alphalink.com.au>]

On Mon, Jul 27th, 2009 at 4:56 PM, John Scanlon 
<riversleigh@outbackatisa.com.au> wrote:

> Also, I learned some stuff about cassowaries on TV last night
> (http://www.abc.net.au/tv/guide/netw/200907/programs/DO0613V001D26072009T193000.htm),
> such as seeing them swallow surprisingly large fruit, and pass
> large quantities of seeds (~2cm diameter, sometimes 'hundreds' at a time...
> add water, wait a bit, and instant thicket!), which clearly must inform
> thinking about behavior involving gastroliths. 

Since cassowaries are mainly frugivores (but don't turn down the occasional 
insect or small 
animal), they probably have a fast digestive turnover. Fruit has been 
'designed' by natural 
selection to be easily digested, to encourage things to eat it. Less time in 
the digestive tract also 
means less chance of the seeds being damaged.

I've always had the impression that gastroliths in herbivores would be of more 
use against hard-to-
digest material, that requires a much longer retention time in the digestive 
system. I know that 
emus use gastroliths, but I'm having a hard time finding any references to 
cassowary gastroliths. I 
suspect they just don't need them (but feel free to correct me).


> ...(but are still easily taken down by a small pack of dogs).

I'm not sure how 'easy' such a kill would be.

I was impressed that it took three large men to subdue a large adult female - 
despite the fact that 
she was mostly tranquilised. Imagine the mayhem had they tried to tackle her at 
full strength!

It was also interesting to see how tolerant of humans cassowaries could become. 
It's obvious 
they're not the intestine-ripping pittiless whirlwinds of fury that some people 
think they are. Of 
course, I wouldn't want to get between a male and his chicks...

-- 
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Dann Pigdon
GIS / Archaeologist                Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj
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