Jim Moore's "AAT Sink or Swim?" Web Site
AAT Claims and Facts: What about Predators?


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.

However, it 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.

Moore argues "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.

First, do 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 different AAH  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.

Moore 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)  under water.

Wetland 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.

Moore's point: "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 predator.

Land-based predators
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.

Aquatic 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?"

Aquatic 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:

1) Are 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 out-compete them.
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