Du Brul 1962; Wrangham 1980; Rose 1977
Classification: Feeding Models
Mnemonic: Hand to Mouth
Specific Model: Other General Feeding / Gathering
Original Proponent(s): Du Brul 1962; Wrangham 1980; Rose 1977;    
Assessment: Popularity: Feeding Models were ranked 2nd (out of 9) most popular in the texts reviewed. 25% of texts referred to general feeding/gathering ideas such as these, hence their inclusion here.
Simple: #19 (=2) / 42 (56%)
Detailed: #23  (=3) / 42 (54%)
Basic Summary: Feeding/Gathering ideas which mostly came after Jolly's specific seed eating but before Kingdon's "squat feeding" model.    
Discussion: This is one of the most vague idea classifications discussed here as it includes a number of related feeding/gathering ideas and overlaps with a number of others too. It is included only  because so many texts on human evolution referred to such ideas that  would otherwise have not been represented in this review. Only Jolly's 'seed eating' hypothesis and Hunt's 'postural feeding' hypothesis were referred to more frquently in this survey.
 Strengths: The main strength of this kind of idea of bipedal origins is that theoretically improves food acquisition and it's very vagueness made it less contradictory to other models.    
Weaknesses: The vagueness of these ideas can also be seen as a weakness too. Apart from theoretically procuring more food they do not offer much else in the way of improved fitness and at best, the model was udged fair in most criteria.    
1.1 Survival Value 3 (Poor) Little survival advantage, other than increased food procurement, is offered by models of this type.    
1.2 Sexual Selection 5 (Fair) This category was judged neutral by this criterion.    
1.3 Not Teleological 7 (Good) One strength of these kinds of ideas is that they do not depend upon some modern human use of bipedalism as a driving force for its evolution.    
2.1 Improved Food Acquisition 8 (Good) These models were judged strongest in this criterion.    
2.2 Accounts for Predation 4 (Fair) This category was judged slightly worse than neutral by this criterion as feeding/gathering food could only make the hominin more vulnerable to predation.    
2.3 Why Apes are not Bipedal 5 (Fair) This category was judged netral by this criterion.    
2.4 Extant Analogues 6 (Fair) This category was judged slightly better than neutral by this criterion because extant apes are sometimees seen moving bipedally when gathering and feeding.    
2.5 Applies to Both Sexes 9 (Good) As this category of ideas applies equally to both sexes it was judged good by this criterion.    
3.1 Hominid Anomalies 4 (Fair) This category was judged worse than neutral by this criterion.    
3.2 Fits Paleoecological Record 5 (Fair) This category was judged neutral by this criterion.    
3.3 Precursor to Strider and knuckle Walker 3 (Poor) Models of this kind do not offer a precursor to both striding bipedalism and knuckle walking.    
4.1 Extended Explanatory Power 5 (Fair) This category was judged neutral by this criterion.    
4.2 Complimentary 7 (Good) The very vagueness of this kind of model tends to make them less contradictory to others and potentially more complimentary.    
4.3 Falsifiable or Testable 0 (Poor) The proponents reviewed here made no testable predictions about their ideas.    
References Du Brul, E. The General Phenomenon of Bipedalism. American Zoologist 2:205-208, (1962).
Rose, M D (1977). Positional Behaviour of Olive Baboons (Papio anubis) and its Relationship to Maintainance and Social Activities. Primates Vol:18(1) Pages:59-116.
Wrangham, R (1980). Bipedal locomotion as a feeding adaptation in gelada baboons, and its implications for Hominid Bipedality. Journal of Human Evolution Vol:9 Pages:329-331