4.1.4: RIVER APES... COASTAL PEOPLE MODEL Algis Kuliukas 2010		Home
Classification: Habitat Compulsion Mnemonic: Wading
Specific Model:	Wading "River Apes" in fooded gallery forests
Original Proponent(s):	Kuliukas (2010)
Basic Summary:	Wading in seasonally flooded gallery forest microhabitats pushed hominins over a rubicon to make them bipedal on land too.
Assessment:	Popularity: This model was classified under the subcategory, "wading habitat compulsion", and was ranked 7th most popular out of 9 categories  in the texts reviewed here. Simple: #1 /42 (=2) (90%) Detailed: #1 / 42 (88%)
Discussion:	My "river apes... coastal people" model is an attempt to pull together the best aspects of all the models of human evolution, some of which have been revewed here. In essence it is a hybrid of the orthodox savannah hypothesis and the so-called "aquatic ape hypothesis". It posits human evolution occurred in two phases, firstly in seasonally flooded gallery forest microhabitats in a broader savannah habitat context. The biphasic exposure to seasonal flooded habitats and relatively open habitats, it is argued ,explains the volution of human bipedalism. Whatvere factors contribute to bipedalism, and clearly it was several components, could only be helped by adding a pressure for wading as it compels bipedalism like no other scenario.
Strengths:	Like all wading models this one has many strengths.
Weaknesses:	est weakness of this model is the increased risk of predation to river-bound aquatic predators such as crocodiles and hippopotami.
Evaluation:
1.1 Survival Value	9 (Good) Like all wading hypotheses this model proposes the simplest and most clear cut survival advantage for bipedalism possible: keeping the head above the water allows the hominin to breathe.
1.2 Sexual Selection	5 (Fair) This model was judged neutral in terms of this criterion.
1.3 Not Teleological	9 (Good) The model is based on extant ape wading behaviour rather thn any modern human phenomenon.
2.1 Improved Food Acquisition	6 (Fair) This model was rated slightly better than neutral because it is placed in relatively food-rich wooded habitat.
2.2 Accounts for Predation	4 (Fair) Any advantage of the proximimity of trees to this model was judged more than compromised by increased threat of aquatic predation.
2.3 Why Apes are not Bipedal	9 (Good) By proposing that human ancestors became isolated from their great ape cousins in East African gallery foest macro habitats it both emraces orthodioxy and also adopts a simple model for explaining Pan-Homo-gorilla divergence.
2.4 Extant Analogues	9  (Good) The model is based on strong empirical evidence in extant apes to switch to bipedalism in water.
2.5 Applies to Both Sexes	9 (Good) The model applies to both sexes.
3.1 Hominid Anomalies	9 (Good) Part of the model sets out to explain, specifically, the anomalies of australopithecine post cranial anatomy in terms of an adapatation to wading.
3.2 Fits Paleoecological Record	8 (Good) The model is consistent with the currently growing paradigm of a wooded paleoecoogical context.
3.3 Precursor to Strider and knuckle Walker	9 (Good) It is argued that the wading model espoused here perfectly acts as a precursor to both human knuckle-walking and Pan/Gorilla knuckle-walking.
4.1 Extended Explanatory Power	9 (Good) The "river apes" phase of the model acts as a precursor to the "coatsal people" phase which, it is argued, explains all the other aspects of human-ape divergence
4.2 Complimentary	7 (Good) This model was designed to be complimentary to as many models as possible and contradictory to as few as possible.Nevertheless it was still judged incompatible with Jolly's seed eating hypothesis, Wheeler's thermoregulatory hypothesis.and Leiberman's endurance running hypothesis.
4.3 Falsifiable or Testable	8 (Good)  The model comes with a set of specifically designed falsifiable predictions.
References	Kuliukas, A V (2002). Wading for Food: The Driving Force of the Evolution of Bipedalism? Nutrition and Health 16:267-289. Kuliukas, A., Milne, N., Fournier, P. (2009) The relative cost of bent-hip bent-knee walking is reduced in water. Homo 60:479-488.