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

Re: Phorusrhacids killing large mammals in National Geographic Channel



On Sat, Aug 01, 2009 at 11:08:06AM -0300, Augusto Haro scripsit:
> ...that does not explain why the maximal prey size of a pack of
> African wild dogs (adult zebra) is the same than that of the much
> larger and more robust hyaenas. Or why a small pack of these dogs, or
> the Cuon, can kill large prey way faster than the more dubitative
> wolf. As you say, sociability does not imply large pack numbers. 

Three things, there.

Extant wolf populations are remnants everywhere.  This is not true of
the African wild dogs or hyaenas.

Prey capture strategy in wolves manages risk by cursorial hunting; it's
not fast, but it's safe.  Not an option for the wild dogs or the
hyenas, both of which have to worry about being robbed by lions and will
have evolved in that context.

Ostriches can run any mammal into the ground.  (Can't out-sprint a
cheetah but the sustained speed would kill anything mammalian.)  The
extant large ratites all run really well.

Assuming from the limbs that a similar running ability is true of
phorusrhacids is only useful for prey capture if it's chasing a
cursorial herbivore that will try to run away for long enough that it
can be run to exhaustion, but it's certainly going to be useful
defensively.

My general expectation is that the last known remains date from around
the start of major continental glaciation.  That's probably enough;
faunal movement south plus climate change, affecting a species in a
dispersed, low-numbers, marginal reproduction niche.

-- Graydon