Re: Phorusrhacids killing large mammals in National Geographic Channel

[Augusto Haro <augustoharo@gmail.com>]

> 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.

As far as I knew, if a lion is in the area, the ostrich gets out
leaving the eggs. The few tapes I saw on such interaction always show
the ostrich running away. I read in an old number of the "Reader's
Digest" of an ostrich breaking the backbone of a domestic dog.

> 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.

The largest representatives of the native South American mammalian
herbivores are Plio-Pleistocene, as far as I know, so the previous
South American fauna had fewer large representatives. By the time of
Titanis, there is other report of a phorusrhacid in Uruguay, South
America, suggesting the group was at least still widespread. Regarding
the extinction of the big birds, I do not know if we can blame so much
the effect of the large northern carnivores as the reason which
extincted all the megafauna, Northern and Southern, carnivorous and
herbivorous. For the largest felids, canids and ursids extinguished
also in South America. Notably, smaller representatives of those taxa
survived, as did smaller relatives of phorusrhacids (seriemas). The
competitive scenario does not explain so well why seriemas were not
displaced by foxes and small cats.