Marc is a physician in the Belgium town of Putte, near Brussels and has applied his medical expertise and knowledge of human anatomy to the  'AAT' since the 1970s.

He is a prolific newsgroup poster and regularly contributes several postings each day on the AAT newsgroup for which he is a moderator and the sci.anthroplogy.paleo newsgroup.

One of his many contributions to the AAT is in providing a more realistic timescale for the proposed 'phase' of greater aquatic adaptation in the genus Homo. Earlier, both Hardy and Morgan had suggested that the 'aquatic phase' may have preceded Australopithecines, at around 6mya. This was met with a great deal of scepticism from many 'traditional' anthropologists as Australopithecines appeared to be quite arboreal and consequently the AAH seemed to be suggesting a phase where an arboreal ape started living in the water, only to return to some arboreality again before then becoming terrestrial. Verhaegen was one of the first people to suggest that this matter might be resolved if one postulated that the last common ancestor of ape and human was already partly bipedal (also partly arboreal, of course), and that much of this bipedality was due to wading. As he put it on 29 March 2002 on the AAT forum "The missing factor is wading IMO, or at least spending part of the time (besides arm-hanging and climbing) in the water: it not only explains the larger body size (thermoregulatory and gravitational reasons), but also the tendency towards truncal erectness of the apes, and the loss of the tail." This meant that the AAH has at least two "more aquatic" phases - one (posited to be in swampy mangrove forests) that preceded the Pan/Homo split, and may have actually been the major speciating factor for all the great apes - and a second (largely coastal) which was post the genus Homo from around 2.6 My. This appeared to answer most of the criticisms of timescale levelled at the AAH at a stroke. Perhaps the best account of this variant of the AAH is that published in TREE in 2002, co-authored with Stephen Munro and Pierre-Francois Puech.

Some AAH proponents, including Morgan and myself, were very sceptical of this idea initially. It seemed to complicate matters. The beauty of the AAH for us was that it seemed to explain the differences between humans and apes, and here was Marc muddying the waters with the idea that, actually all apes were already partly aquatic. For me, the turning point came in December 2000 with the discovery of Orrorin tugenensis, a putative biped and an even more putative hominid. It seemed to me that here was a possible bipedal ape dated (at 6Ma) at around the time, or even before, the widely accepted molecular dates for the last common ancestor, at around 5.5Ma. Having just listened to a paleoanthropology lecture by Mark Collard at UCL, extolling the accuracy of the molecular clock, I was rather surprised when, just a few days later, that the same guy made an announcement to the weekly departmental meeting suggesting that this fossil discovery was no big deal. Well it was a big deal to me and I wrote to Marc immediately congratulating him on his idea and voicing my support from that point on. It is probably true that most AAH-proponents today now support a model of human evolution that is based on an early wading-climbing phase for all apes and a more coastal-littoral phase for the genus Homo.

Selected Readings

Verhaegen, Marc (1985). The Aquatic Ape Theory: Evidence and a Possible Scenario. Medical Hypotheses Vol:16 Pages:17-32

Verhaegen, Marc (1988). Aquatic Ape Theory, Speech Origins: a hypothesis. Speculations in Science and Technology Vol:11 Pages:165-171

Verhaegen, Marc (1990). African Ape ancestry. Human Evolution Vol:5: Pages:295-297

Verhaegen, Marc (1991). Aquatic Features in Fossil Hominids?. In: Roede, Machteld; Wind, Jan; Patrick, John; Reynolds, Vernon (eds.), (1991). Aquatic Ape: Fact of Fiction: Proceedings from the Valkenburg Conference. Souvenir Press (London)

Verhaegen, Marc (1991). Human Regulation of Body Temperature and Water Balance. In: Roede, Machteld; Wind, Jan; Patrick, John; Reynolds, Vernon (eds.), (1991). Aquatic Ape: Fact of Fiction: Proceedings from the Valkenburg Conference. Souvenir Press (London)

Verhaegen, Marc (1992). Did Robust Australopithecines Partly Feed on Hard Parts of Graminae? Human Evolution Vol:7 Pages:63-64.

Verhaegen, Marc (1993). Aquatic versus Savannah: Comparative and Paleo-environmental Evidence. Nutrition and Health Vol:9 Pages:165-191

Verhaegen, Marc (1994). Australopithecines: Ancestors of the African Apes? Human Evolution Vol:9 Pages:121-139

Verhaegen, Marc (1995). Aquatic Ape Theory, Speech Origins, and Brain Differences with Apes and Monkeys. Medical Hypotheses Vol:44 Pages:409-413

Verhaegen, Marc (1996). Morphological Distance Between Australopithecine, Human and Ape Skulls. Human Evolution Vol:11 Pages:35-41.

Bender, Rebato; Verhaegen, Marc; Oser, Nicole (1997). Acquisition of human bipedal gait from the viewpoint of the aquatic ape theory. Anthropologischer Anzeiger Vol:55(1) Pages:1-14

Verhaegen, Marc; Munro, Stephen (2000). The Origin of Phonetic Abilities: A Study of the Comparative Data With Reference to the Aquatic Theory. ? Vol: Pages:1-12

Verhaegen, Marc, Puech, Pierre-Francoise (2000). Hominid lifestyle and diet reconsidered: paleo-environmental and comparative data. Human Evolution Vol:15 Pages:151-162

Verhaegen, Marc; Puech, Pierre-Francoise; Munro, Stephen (2002). Aquarboreal Ancestors? Trends in Ecology and Evolution Vol:17 Pages:212-217

Algis Kuliukas
April 2006