Re: Phorusrhacids killing large mammals in National Geographic Channel

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

On Sat, Jul 25th, 2009 at 7:52 AM, Erik Boehm <erikboehm07@yahoo.com> wrote:
 
> Apparently these birds are considered doomed from minor abrasions caused by 
> cats - their 
immune
> system appears to be too weak to fend off an infection from a superficial 
> cut, or at least a
> bite.

Some cage birds are known to drop dead at the drop of a hat. Lack of exercise, 
poorly balanced 
diet, and inbreeding could well be the main contributers. Many cage birds are 
highly social species 
in the wild, so if they're kept alone in a cage they can develop psychological 
problems as well. 
Stress or depression are known to reduce immune response.

I've seen wild songbirds survive cat attacks - although it's not often that a 
cat botches the job. I 
suspect that wild populations have much greater selective pressure against poor 
immune systems. 
Captive-bred birds are often bred for their looks rather than their health. As 
far as some 
unscrupulous breeders are concerned, they only have to survive long enough to 
be sold.

Cat bites in particular are prone to causing infections in just about any type 
of animal. Even cats 
themselves often develop huge pusy abscesses after being bitten.

> Is it likely a Phorusrhacid would be similarly doomed by a defensive bite 
> from a mammal?

Given that they probably fed on carrion at every opportunity (as most 
carnivores will), I'm 
guessing their immune systems were probably somewhat more robust than that of 
the average 
cage bird. However I imagine any deep puncture that compromised their system of 
air-sacks would 
have been considered a serious injury.

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