This might be seen by many as Moore's most convincing page to date. He makes
a pretty good case that the threat of predation of big game savannah
predators is, perhaps, not as bad as some might have argued and also
compiles a pretty awesome list of references which would scare any would be
wading hominid to death, even at the thought of dipping their toe in the
water. To cap it all, for the first time on his web site Moore even goes to the
trouble to provide actual references to the source of his claims about what
AAH proponents argue.
On this page I can find
nothing that might be characterised as a misrepresentation of the AAH
argument, although he does rather exaggerate the amount of time the wading
origins hypothesis proposes early bipeds would be in the water and the depth
of water that would require them to doing so bipedally.
Overall I think Moore makes a good case for the very
serious predation counter-argument to the AAH. It is an argument that
certainly cannot be dodged easily.
can be argued that perhaps Moore does overstretch his 'chimps have no
problem with leopards, so hominins probably had no problems either' argument
and does, rather over-exaggerate the croc and shark threat, deftly
interweaving evidence about human interaction with Australian salt-water
crocodiles into the argument about African hominins in the blink of an eye.
Perhaps the best response here is to simply remind the
reader that the AAH is not proposing that human ancestors were, in any real
sense, aquatic. It proposes that they moved through water more than our ape
cousins did. Therefore it should be considered that living at the water's
edge and evolving relatively strong abilities to swim and dive (compared to
most terrestrial predators) would have provided our ancestors with a rather
effective way of avoiding land based predators, whilst our undoubted
abilities on land and in trees would have uniquely doubled up to provide
possible the most effective way of avoiding aquatic predators too. Once
again, it is at the land-water interface where the AAH makes most sense.
What about Predators?
Moore starts this page with a valid point. He writes: "No matter where
the transition [from ape to man] is said to have taken place, any attempt to construct a
theory about early human evolution must contend with, among other things,
the problem of predation and how to avoid it (as much as possible)."
Moore seems to claim that the chimpanzee method of dealing with predators,
though group cohesion and intelligence, is all we need to dismiss the
problem in early hominins. If one assumes that early hominins lived in
closed forest habitats, like chimps, then it probably would suffice but as
most models are based on some kind of move to more open, and dangerous,
habitats perhaps this view is a little facile, particularly when you
consider that these apes were in transition between two completely different
forms of locomotion..
His arguments against the aquatic argument for wading bipedalism are,
perhaps, also mistaken.
Firstly, about the amount of time spent wading in water, he suggests that
"we would have to assume that it must have been most of the time spent in
locomotion, or we wouldn't expect bipedalism to be adopted for the
reasons the AAT suggests."
Moore assumes just two such reasons: The first, "if the hominids weren't
bipedal, the water would be over their heads", hardly needs a great deal of
time to work, however.
The second, that wading would "support the weight of the hominid, lessening
strain" does imply a greater amount of time in water, true, but there are
many other reasons an ape might wade which do not require any great deal of
time spent there.
Hardy's original suggestion, that it was to collect food, would certainly
not require 'most of the time spent in locomotion' but just a significant
part of it.
Helping to cool down would only take seconds and crossing a stretch of water
to get to another clump of trees or to the other side of a river might only
take a minute or two.
It is interesting that
opponents of the wading model assume that the hominin would have had to
adopt wading for hours on end, whereas such assumptions are usually not
required for other models.
Moore writes "Both these requirements of the theory
suggest that we're talking about spending many hours a day in water that is
considerably more than waist deep." Of course he would do that on a page
about predation (his next sentence starts... "This makes for an enormous
amount of exposure to common and vicious predators..."), but it does not
change the fact that in even very shallow water apes tend to move bipedally
and tend to do so even for just a few seconds at a time. (Kuliukas 2002)
The point is that anything that might get one group of
early hominins to move bipedally more than another group, that could
be selectively advantageous, is going to make a difference. In waist deep
water apes have simply no choice but to move bipedally, so it is logical
that apes living in wetland habitats are more likely to adopt bipedal
locomotion than those that do not.
"most AAT write-ups also make statements about the lure of this water
environment for safety from predators. However, rather than being a haven
from predators, this environment would not only expose such hominids to a
great number of predators, but also predators which seem much harder to
defend oneself from" but, again, he seems to exaggerate the point.
It is not that the AAH is arguing that hominins became fully aquatic. It's
very important to remember that. It is arguing merely that they became more
aquatic. Assuming this means that a hominid that could swim quite well would
have at it's disposal a mechanism of escape from several land-based
predators that was not available to hominids that were less able in water.
Of course it is equally true that such a water-side dwelling species would
easily be able to escape the kind of aquatic predators Moore is keen to tell
us about, too: By leaving the water, returning to land and perhaps climbing
a tree. Moore omits that part of the argument but it is at the
land-water interface where the AAH predation argument works best.
AAT proponents claim that an aquatic environment was safer than land?
Moore then does something unusual on his web site. After seventeen pages
of not giving references to back up his allegations of AAH claims, he
finally decides to do so. On this page he gives specific references to three
proponents (Hardy, La Lumiere and Ellis) who actually did make such claims.
It is a pity he didn't do this before, it would have saved a great deal of
time in writing this critique.
summarises the three citations by writing "Note that even without
considering aquatic predators, the idea of hominids escaping land-based
predators such as lions by 'running back to water and swimming away' is
problematic, since large cats such as lions often hunt by water holes,
streams, etc. and chase their prey into the water and kill them there" but
doesn't speculate as to whether they would do so when chasing species that
were able to dive and swim relatively well (compared to the lions)
habitats are clearly not ones to which the large African predators have
specialised. Moving through a marsh with tall sedges is likely to be far
easier for a biped than for a quadruped, making it a relatively safe habitat
for our hominin ancestors.
"Since human swimming speed is much slower than human running speed, the
usefulness of this method of escape seems to be an assumption that doesn't
hold water" is easily countered by the suggestion that human underwater
swimming speed is in all probability faster than that of any African savanna
How chimpanzees react to predators
Moore then provides a fascinating piece of evidence from Kortlandt's
investigation of chimpanzee reaction to a stuffed leopard. The study indicated
that chimpanzees, particularly those used to more open habitats, are not
fearful of leopards and will actually mob them, with sticks and rocks.
It is a very compelling argument that early hominins would have had
fewer problems than one might think with large African predators.
Predators - Crocodiles
Moore then provides a fair amount of anecdotal evidence indicating that
crocodiles are very dangerous creatures and probably were at the time of the
divergence of hominins from the African great apes.
He covers the subject from an impressive number of perspectives, answering
questions like "how do we know there were crocodiles in eastern Africa at
the time of the transition?" and "what about defence? What about spotting it
coming and getting out of the water?"
predators - Sharks
The predators page is completed with more anecdotal evidence about how
dangerous sharks are to humans too.
Jim Moore makes some good points on this page. The predation argument
against the AAH is a serious one and cannot be dismissed easily. Crocodile
predation would be as significant a threat to a any would-be wetland ape as
sharks would be to any would be off shore diving hominin. However, we need
to get the debate into some balance.
Some opponents to the savanna hypothesis have, perhaps, over-stretched the
argument that African big game predators would be the death knell to any
nascent bipedal species wandering out there in the early Pliocene. But if
that is true, it certainly would appear to be mirrored by Moore's choice of anecdotal
evidence for the prowess of aquatic predators.
There are some
important counter-points that need to be fed into the equation:
Awash Valley Crocodilians the same as Nile Crocodiles?
First of all, the crocodile species in the Awash valley, where many hominid
fossils have been found, do appear to be, rather oddly, smaller and far less
dangerous than their cousins which live to the north in the Nile.
In Don Johanson's book 'Lucy: The Beginnings of
Humankind" he provides the following: "Some members of the expedition would
not swim at all because of the infestation of the river [Awash] be
crocodiles. But these were smaller than the man-eating monsters of Kenya and
Uganda, and did not seem to be consuming any of the local Afar people, who
were in and out of the water constantly. After a couple of weeks most
scientists were bathing daily (Johanson 1981:151)."
According to the literature, the species of crocodile living in the Awash
valley is classified as Crocodilus niloticus, like their more
ferocious cousins to the north, but it remains an intriguing possibility that
this species or sub-species is somehow smaller and less dangerous to humans
than the man-eating varieties that Moore is so keen to promote.
One might even speculate as to the reason for this difference. Perhaps
millions of years of competition with intelligent hominins - a competition
in which they ultimately came out second best - left them relatively
impotent. Or perhaps it was the extreme variations in climate and hydrology
of the region - wet cycles followed by periods of aridity overlain by many
significant volcanic events - which continually kept culling back the
population of the larger man-eating class of crocodiles in that region.
2) Are man-eating crocodiles found in all the possible
water-side habitats of early hominins?
Jim Moore offers a great deal of evidence about the dangers of
crocodiles, much of it is from anecdotes from Australia with the much feared
'salty' (Crocodilus porosus) which, of course, does not live in
Africa and probably did not do so during the early Pliocene.
It is interesting that the chimpanzees at the coastal lagoon Conkuoati
refuge, in the Republic of Congo apparently have no fear of stepping into
the estuarine water. There are crocodiles further up stream in the Congo
river itself but they seem to avoid going down stream too far perhaps
because the salinity of water starts to become intolerable for them.
It is possible that hominins living around the salt lakes of the East
African rift valley were also relatively safe from the risk of predation for
the same reason.
3) What about an
intelligent response to the 'croc threat'?
You can't have it both ways: Moore argues that hominins would meet the
threat of big cat predation with intelligence and a measured group response
but when it comes to aquatic predators that they'd just be dumb and have no
response at all.
If human ancestors lived by the water's edge for most of their ancestry, they
would undoubtedly have built up a great deal of expertise in how to avoid
them and how to deal with them.
In the early phase of human evolution our ancestors were certainly largely
arboreal, which would have provided them not only with the perfect refuge
from crocodiles but also the perfect vantage point from which to observe
their movements and learn about how to avoid them and ultimately, how to
Later, it is interesting to speculate whether the ability to use and make
sharp stone tools was related to deterring crocodiles. Anecdotes from people
living in areas infested with alligators suggest that throwing big boulders
into water where alligators are present may be sufficient to move them along
and the large collections of stone tools found, many often in almost perfect
condition, in East African sites suggests that perhaps this might have been
one of their functions in early human evolution too.
It is interesting to remember that for most of the last century the
prevailing model of human evolution proposed that it was the undoubted
hardship of life on the great arid plains of the African savannah which led
to the process of hominization and ultimately to the increased intelligence
of our ancestors. It might be suggested that learning how to share a habitat
with and ultimately overcome the threat of crocodiles would have provided an
even greater challenge.
Johanson, Donald C (1981). Lucy: The Beginnings of Humankind. Simon &
Schuster (New York)
Kuliukas, Algis Vincent (2002). Wading for Food: The Driving Force of
the Evolution of Bipedalism?. Nutrition and Health Vol:16 Pages:267-289