Re: Phorusrhacids killing large mammals in National Geographic Channel

[Raptorial Talon <raptorialtalon@gmail.com>]

> It seems weid to me that a tall bipedal bird can make a shorter and
> stockier quadrupedal mammal its same size (say, a boar-sized one) to fall 
> with kicks (although perhaps I underestimate the bird or
> overestimate the mammal resistance).

I'm under the impression that ostriches can (on at least some
occasions) successfully defend themselves from lions through kicks,
inflicting some fairly serious damage to the lion in the process. If
that's true, then a large phorusrhacid should have had legs powerful
enough to at least cripple or stun prey to be finished off with the
beak. I guess.

> May be that they were dominant (the idea of the kill site >antagonisms 
> reminds me of the ugly image of the Titanis killing >Smilodon gracilis by 
> using a woodpecker's technique), because the >bird is tall and may have 
> screamed as many birds intimidating the >smaller carnivores. In addition, if 
> it can kill a human-sized mammal, >the same can go to a leopard-sized animal. 
> However, a leopard->sized carnivore may have as well been dangerous for the 
> relatively >lightly built bird.

True; that would depend on the mammal having the element of surprise,
however, at least as far as the bigger phorusrhacids are concerned.
Not that both parties couldn't inflict some unpleasant wounds.

> However, I am not sure about the fact that big game would be not >used as a 
> resource without the intervention of the birds, after all, by >the Pliocene 
> you also have saber-toothed marsupials, which even if
>leopard-sized, would pose threat to tapir/horse-sized mammals.

Yes, but for what, 10-25 million years before the Pliocene, placental
predators were absent from South American ecosystems. And despite the
apparent success of *Titanis,* it seems that the phorusrhacids died
out not too long after placentals arrived. That may be more than
coincidence, I suppose.

Also, weren't the marsupial predators pretty much all non-cursorial,
despite living in a region where cursorial to semi-cursorial
herbivores were the most common prey animals? If that's correct, it
seems pretty odd just in and of itself . . .
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>I have it on good authority that the biomechanics of a phorusrhacid >skull has 
>been the subject of a very recent investigation.  A >publication is just 
>around the corner (or two)...

Nice, I'll have to check into that sometime.