Re: Repost on predation

J. Moore (
Thu, 16 Nov 95 15:33:00 -0500

Tom Clarke recently posted asking why I hadn't replied to a
previous post of his; it was, as he thought possible, that my
system had seen fit to swallow it before it got here. I dug it
out of the sci.anthropology.paleo archives and here's my reply; it
covers many of the same points that were covered this past summer
in an extended session of posts with another newsgroup participant.

Thomas Clarke (
27 Oct 1995 15:18:43 GMT

JM> One is that predation happens, sometimes. It doesn't matter much
JM> *unless* there's too much of it. When the animals can't at least
JM> replace their population, there's a problem. Populations may get
JM> smaller for a while, and often do, but if a population goes year
JM> after year without being able to replace its numbers, it can't last.

TC> Yes. This is a truism.

Let me explain why I felt I needed to point out such a seemingly
obvious point. I can do so with a later sentence of yours:

TC> Yes people are occassioally killed by lions, and bears, and sharks
TC> and crocodiles, and snakes, and spiders, and ...

It was said that the the issue of predation was bogus because
"there are predators everywhere" and with lines like yours above.
It seemed to me that people were not understanding the
crucial significance of the amount of predation, vis a vis
population replacement, so I strove to make this admittedly simple
point very clear.

>From here on, to cut down the size of the post (uh oh, this sounds
like those notices on federal forms re the paperwork reduction
act ;-), I'm gonna try to outline my previously-quoted words to give
an idea of what Tom was responding to:

JM> Another is that, for the transitional population, we can surmise,
JM> <snip> an animal that is similar in mental and physical abilities
JM> to chimpanzees, and so can use that species' proven ability
JM> to survive in open savannah woodland as a model
JM> for how our ancestors could've done the same. <snip>

TC> OK. Chimps are still around as a species so predation had to be less
TC> than the replacement rate.

And this demonstrates that terrestrial hominids could've handled
their predators.

JM> We have a problem in doing this for a proposed water-based
JM> transitional hominid population. They would've faced <snip>

TC> Here is where you loose me. "numerous, vicious" is pretty vague.
TC> How numerous? Need to quantify.

Shortly before my first posting of this bit on predation, I posted
some rather long informational posts on crocodiles and sharks vis
a vis predation. They would be in the archives around the end of
June 95. I would hope I don't have to repost all that again, but
suffice it to say at present that crocodiles are extremely
numerous in Africa and have been for millions of years. The
environment they live in allows them to mass in large numbers,
unlike land-based predators, as probably any nature show on the
tube would show. The vicious part I'll talk about a few lines

TC> How vicious? My experience is that alligators will attack bite
TC> sized things like small dogs, but the circumstances have to be
TC> unusual for larger animals to be attacked.

This is not unusual, however, for Nile crocodiles, which commonly
attack zebras, wildebeest, and even Cape buffalo. Adult Nile
crocodiles weigh in at up to 2,200 lbs.

TC> The water born predators are also dumber than the mammalian land
TC> predators. I don't see any great problem in avoiding them.

This point about crocs being dumber than land predators was
brought up before; it actually makes them more of a problem rather
than less. First, you can't "avoid" them unless you just stay out
of the water; and attacking crocs are rarely seen before they attack.
If they were smarter, they might respond more readily to threat
displays or fighting back, but large attacking crocs do not
respond well at all (remember in Blazing Saddles, when Gene Wilder
told Cleavon Little not to shoot Mungo cause "you'll only make him
mad"?). I recently quoted some info from a study of actual
attacks on people by large Nile crocodiles and these crocs were
undeterred even though they "were either repeatedly stabbed with
spears or knives, beaten with sticks, pelted with stones, or had
sticks rammed down their gullets in order to prise the human victims
from their jaws...but to no avail" (Pooley et al., 1989: 175-176,
"Crocodilians and Humans: Attacks on Humans" by A.C. (Tony) Pooley,
Tommy C. Hines, and John Shield. In *Crocodiles and Alligators*
Consulting Editor, Charles A. Ross Facts on File: New York and Oxford).
They also note that there is no safety in numbers for humans in
dealing with crocodiles, unlike land-based predators.

TC> Much of course depends on exactly how the proto-hominids interacted
TC> with the water. That should be the subject of debate.
TC> Your argument at best eleminates versions of the AAS where the
TC> apes spend continuous amounts of time in water frequented by
TC> crocodiles.
TC> That is they could not have lived an otter-like lifestyle.

The AAT's main point has always been that bipedalism could not
evolve on land, but only in water, and for these AAs to become
bipedal (quite rapidly) rather than simply remaining as they were
(locomotor-wise) they must have been using the water during the
majority of their locomotor use. The AAT also requires that these
AAs were in deep water, above their waists, during that time;
otherwise their locomotor activity is not demonstrably different
from a terrestrial hominid. Wet feet don't make an aquatic ape.

Therefore they must have been spending a great deal of their day
in water that's more than waist deep. The only remaining versions
of the AAT (none by "official" AAT writers) are those which
suggest these AAs frequented areas of heavy surf or certain
mountain lakes without crocodiles; neither version has suggested
plausible reasons why these AAs did not simply remain in trees or
on land, given that they would have to make big changes in their
behavior to take up their water dwelling.

JM> The point is that avoiding all predation isn't what's needed, just
JM> avoiding *enough* predation. What "enough" is depends on how many
JM> kids you've got to spare. <snip>

TC> What is this about? Are you comparing ape mammals to crocodile
TC> reptiles?

I'm comparing species with low child-rearing rates with species
with species with high child-rearing rates; gathering-hunting
humans and chimps, and to a lesser extent gorillas, have very low
child-rearing rates, much lower than even marine mammals such as
whales (which makes it rather ironic that we are presently pushing
them to extinction). Very much lower than animals that can
withstand a great deal of predation, including crocodiles, fish,
and indeed all aquatic animals that aren't extremely large.
Therefore, since no animal with anything close to our ancestor's
likely rate of child-rearing exists in an aquatic environment,
I suggest it's likely that this is because they can't.

JM> One other thing is what we can tell from the records of predators
JM> and modern human populations. One thing we *can't* say is that these
JM> predators were not a problem because they don't kill most of the
JM> human population today. <snip>

TC> Do you have quantitative figures for death by crocodile versus death
TC> by land predator? Indians lived in Florida successfully before
TC> Columbus.

The above (partly snipped) explains why we can't use our survival
as a species, or comparitive death rates of modern humans, as
meaningful info regarding a postulated aquatic transitional
population. To start with, the majority of our population does
not stand around in waist deep or deeper water half the day. In
fact, the vast majority of our population doesn't live where their
are significant non-human predators at all.

TC> I don't see the problem.
TC> Life is dangerous, the world is full of predators, both on land, sea,
TC> and air. If chimps can cope with cats and snakes, I don't see why
TC> australopiths can't cope with crocs.

See above re birth rates, etc.

JM> and have no appropriate, applicable model for our ancestral
JM> population which shows us an effective strategy for dealing with
JM> this problem.

TC> So they stay out of the water when necessary. Good time to go look
TC> for fruit.

I agree completely; they would certainly have stayed out of the
water when necessary and looked for fruit, vegetables, and meat.
Unfortunately for the AAT, "when necessary" would be "virtually
all the time", leaving hardly any time in water to rapidly evolve
all those claimed aquatic features.

TC> That's why the Australopith water would slap the hell out of the kid
TC> it went near the water without an adult ... The adults have behaviors
TC> that help maximize the young's probability of survival.
TC> Tom Clarke

Since there is no safety in numbers when dealing with crocodiles,
and since attacking crocs are rarely detected before the attack,
and since they don't respond to counter-attacks after attacking,
the presence of adults would not help. I agree that the adults
would have "behaviors that help maximize the young's probability
of survival", such conservative behavior by adults in contrast to
youngsters (for food and potential predators) has been documented
in Japanese macaques, for instance.

Since there is no safety in numbers when dealing with crocodiles,
and since attacking crocs are rarely detected before the attack,
and since they don't respond to counter-attacks after attacking,
that behavior would almost certainly be keeping youngsters away
from the water most of the time -- hence, no aquatic ape.

Jim Moore (

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