From: J de Lyser (gd33463@glo.be)
Date: Wed Jan 22 1997 - 04:01:31 MST
Keith Henson <keith@filoli.com> wrote:
>>I think early Australopithecus had to deal with far fewer predators.
>I seem to remember reading that one of the sites where a lot of Lucy's kin
>were found was originally a cave under a tree where the local leopards
>dragged their kills. The skulls had puncture marks which fit the tooth
>spacing of the leopards of that time. Keith Henson
I know, someone reminded me of it, and i've been looking for more data on
it. zoology data shows that panthera genera (leopard/lion/tiger) didn't
develop until 2.5 million years ago, afarensis is supposed to have been
replaced by habilis then. Recent theories show that various types of
homonids may have overlapped eachother by a lot more time than was assumed
before.
There are three answers for the specific case of the cave with the
australopiticene skulls.
1) it were not leopard marks, but acinonyx marks
2) it were primitve leopard marks, and lucy's kind lived longer than assumed
3) the zoology data about panthera species is incorrect.
Whatever it was (i'd go for 1 or 2), i do seem to recall the paleontologist
who showed the specific skull in the documantary ('in search of our
ancestors', i had it on tape, but can't find it back) suggested it had been
an older afarensis or that it was cought in some swamp or something to that
extent.
In any case it's more than a little remarkable that there is so few data
about a possible big cat ancestor who could have hunted the occasional
afarensis. I needed that data to establish the relative treath to afarensis
it could have posed. But the example of the chimps in my previous posting
shows that whatever risk it was, it was not as big as John Clarke suggested.
As i said before, any big cat who lived around lucys time, can not be
compared to modern big cats, there's a 4 million year period of development
and natural selection between them. And other data has suggested that
afarensis was quite capable of defending himself against predators. Therefore
afarensis did have a predator, but a predator who prefered an easier prey.
In any case Afarensis was definitely not 'main course' on the menu of
whatever proto- big cat lived in the same period. And that wasn't how it was
described by previous posters on the subject.
>From: Omega <omega@pacific.net> wrote
>> Maybe the only real competition of importance to Afarensis (and >>
pre-hominids in general) were ...other Afarensis /hominids!,
>> This might explain the much faster evolution (intelligence increase, body
>> size etc) of homonids compared to most other species.
>Which brings us to the most likely theory regarding the latter phases
>of our pre-human evolution -- an unterminated positive feedback loop of
>Afarensis/homonids competing against same. A process that would have
>would presumably terminate only after having driven the evolution of
>human form to some physiological limit once they started throwing stones
>and/or words/protowords at each other on a regular basis.
>About the earlier phases when we were supposedly acquatic. I find that
>troublesome either way. Without large carnivourous land predators,
>"chimps throwing rocks" are pretty much on top of the food chain and so
>"the evasion of predators", one of the big calling cards behind the
>"wading ape theory" takes a big loss. Still the diving reflex, fur-
>lessness, salt metabolism, subcutaneous fat, and newborn swimming
>ability (to the extent that these things hold up factually) do seem
>to be better explained this way than otherwise. Seems like the mystery
>of this earlier phase only deepens.
I've downloaded over 100 postings in the paleontology newsgroups that dealt
with predators and aquatic ape theory. All of them spoke of a catlike
predator (mostly mistaking lions and leopards for having been around at the
time) but none of them supplied the name of the creature. I'm 90% sure any
predecessor of panthera genera couldn't have been around at lucy's time, and
if it was, it was in its infancy, far from the maneater modern lions and
leopards are.
All cats developed from civet genera (hyeanas as well), they developed from
a creature one and a half times the size of a modern house cat to what they
are today. Any big cat that developed before the main group of big cats
(panthera) must have been acynonix genera.
***The one thing i may have overlooked is that panthera genera probably
developed from a large species of proto-acinonyx. So at best we have a
transitional acinonyx-panthera at lucy's time (again: of which there doesn't
seem to be any name or data).
The last remaining acinonyx is the cheetah (a. jubatus), some info on the
cheetah:
>Cheetahs aren't good hunters either. Even though they can run very fast,
>they can only do so for a short period of time, so they have to get very
>close to their prey in order to have a chance of catching it. Many young
>cheetahs make the mistake of starting their attack too soon and get tired
>before they catch it. Once they catch their prey, they aren't good at
>defending it either. Often cheetahs are so exhausted from chasing their
>food, they can't even protect it from being taken by hyenas.
<snip>
>Cheetah's don't have sharp claws. Cheetah's claws don't retract all the way
>like other cat's claws do, this is to help them keep from slipping at high
>speeds, because of this, their claws are dull and more like dog's claws.
Any proto species of acinonyx which lead to the panthera genera must have
been something between a primitive cheetah and a primitive lion/leopard.
Note: not a cross between a MODERN cheetah and a MODERN lion, but at best a
cross between an underdeveloped cheetah and an underdeveloped lion. Lacking
4 million years of rapidly upward spiraling natural selection.
Any comparison made between afarensis and this proto big cat, would sooner
be a comparison between modern man and modern big cat, than between a chimp
and a leopard. And even chimps have shown they can handle a leopard !
I hope my point is taken.
As to aquatic ape theory, i don't support it, but i don't ignore their
criticism either, it's an interesting theory which is worth thinking about.
The problem with AAT supporters is that what they accuse their opponents of
-being stuck in dogma- reflects to some of them as well. What i don't like
is the ease with which generalizations are made in comparing modern
creatures with prehistoric animals. I've done it too in my recent posts, but
i've always added comment that it should not be forgotten its not the same
species we're talking about, but a modern, better developed version.
Even assuming that the data about panthera genera is incorrect, the fact
that 4 million years of development has gone by makes a big difference. If
prehistroic big cats are only a fragment underdeveloped compared to modern
big cats, of what afarensis is compared to modern man, i would still summon
up Afarensis like this:
He was the most intelligent creature that lived, well capable not only of
defending himself aginst even the most ferocious MODERN predators, but not
affraid of them, and killing it's young whenever it could.
AFARENSIS WAS THE KING OF HIS JUNGLE !
J. de Lyser
Brussels
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