Re: EVOLUTION: The Aquatic Ape

Jay Reynolds Freeman (
Fri, 24 Jan 1997 21:00:10 -0800

> Still this says very little about those Nimravidae, i know
> sabertooths were big (fatalis WAS as big as a lion), i also know
> they were not very smart,

I am commenting a little out of sequence, but even if we had a clear
idea of how cranial capacity correlated with "smartness", it is not
clear to me how one can infer much about relative cranial capacity
from exterior skull morphology when comparing such rather different
genera as _Pantera_ and _Smilodon_. It takes a lot of structure to
support those big teeth, that jaw, and the muscles which move them;
one would expect the shape of the skull to be considerably different
in consequence.
Furthermore, if sabertooths used their canines for close-quarters
slashing attacks, evolution might have favored a more enclosed and
robustly protected brain. I suspect there are cranial-volume
measurements somewhere to look at; it would be wise to dig them out.
In the absence of data, 5 My is not a long time in the history of
mammals -- which after all, go back some 230 My (to the split with
reptiles); one would _a_priori_ expect great differences in
intelligence across the former span to be the exception (as with
hominids) rather than the rule.

> but more importantly, they didn't live in Africa.

Um, certainly they did. If memory serves, genus _Smilodon_ and
perhaps a larger taxon was new-world only, and _Smilodon_ is what most
people popularly call "the" [sic] saber-toothed tiger. Yet there were
lots of other large-toothed cats, distributed worldwide. Have you
possibly confused the limits of _Smilodon_'s range with the limits of
all large-toothed cats? _Homotherium_ is one genus whose distribution
included Africa. I am pretty sure there were lots of others,
including large ones, but I would probably have to hit the library and
dig some to find out which -- I don't think the information is in the
texts I have at home. I think I recall from previous postings that
you have been searching the web -- I think what you have to do is
search library stacks, or find an on-line abstracts database and dig
through that, or perhaps merely a good paleontology book.
Based on the thirty-or-so million-year history of the cat family,
its widespread general success (as still evident today), and the
several separate occasions on which it has spawned lion-sized
predators, one might well argue that in any Miocene or later
new-world, Eurasian or African environment in which large game was
present, large cats would have been present to feed on it, but one
doesn't need to be nearly so wishy-washy; there is data. If you wish
to use absence of evidence as evidence of absence (of large cats in
Pliocene and Pleistocene Africa), I don't see any way to avoid turning
over every scrap of evidence that has been published, and I fear that
most of it is not on the web.

Actually, I myself don't have any problem with the idea that
_Australopithecus_afarensis_ could cope with the presence of large
cats in one way or another, as I have indicated in other postings on
this thread; that is, I don't think one needs to assume that for
_A._afarensis_ to have survived, it must have only encountered small

Incidentally, there has been some rather interesting work done on
food-source selection; given a wide variety of choices of foodstuff,
most animals tend to specialize on only a few. There seems to be a
tradeoff involving how much effort one spends to get food and how
much food value one gets by doing so, that has a rather sharp cutoff.
Thus most predators are capable of taking a much wider variety of prey
than they usually do (and will switch habits if a more preferred species
should become scarce, or for some other reason). One must thus
distinguish carefully between whether a predator can take a particular
kind of prey, and whether it actually does.

> Many other homonid and homonoid species were bipedal, why didn't they
> develop intelligence ? why did they become extinct instead, just because
> there was one who was better ?

That seems to me like an entirely sufficient reason...

> Did it say if [early stone tools were] found alongside habiles
> skeletons or among afarensis ?

Probably just "found", not necessarily in close proximity to hominid
remains. One rarely has such luck.

Jay Freeman, First Extropian Squirrel