Neanderthal Morphology

H. neanderthalensis differed from us in many respects. Morphologically speaking they tended to be shorter and more robust, and thought their brains were larger than ours, their neo-cortical ratio was still smaller. This page is particularly devoted to aspects of Neanderthal Morphology and various theories that purport to explain it.

Post Cranial Morphology

Special features and adaptations of the Neanderthal post-cranial skeleton: Cold climate adaptation?

Introduction -

Much has been said recently in the debate on Neanderthal morphology and the transition to so-called modern H. sapiens(Trinkaus 1983; Rak 1986; Stringer 1983, 1995), but interestingly this has sparked debate on just why the post- cranial skeleton of H. neanderthalensis exhibits the unique features seen in Neanderthal. The classic answer is that it is a cold climate adaptation, but this has recently been questioned (Rak 1990; Shreeve 1995). Other environmental factors include lifeway patterns (Geneste 1988; Stringer and Gamble 1993; Tattersall 1995; Mellars 1996) as well as tool morphology and innovation(Binford 1969; Stringer and Gamble 1993; Trinkaus and Shipman 1993).

The purpose of this brief paper will be to highlight the differences (as compared to H. sapiens) in the post-cranial skeletal structure of Neanderthal and then to attempt to understand why and for what reasons these characteristics manifested themselves. For sake of brevity, we will leave out the contentious issue, though in our opinion an all but answered one, of whether Neanderthal evolved into modern human beings or not (Brace 1964; Wolpoff 1980, 1989; Stringer and Gamble 1993, Shreeve 1995; Tattersall 1995).

Post Cranial Morphology -

The post-cranial morphology of Neanderthal differs from modern human beings in five basic aspects: (1) general robusticity as seen in tubercle and tuberosity formation and size as well as tibial/femoral cross sections, (2) tibia/femur ratios, (3) pelvic area, (4) carpal/metacarpal thumb joint articulation and, (5) scapula.

Robusticity -

The general robusticity of Neanderthal can be attributed by the large muscle attachment area on Neanderthal bones, expecially the long bones. Though this is manifested as a slight "bowing" of the long bones, this curvature is a direct result of the large muscles that the Neanderthal skeletal structure supported. The deltoid, pectoralis major and radial tuberosities are massive, belying the underlying strength in pronation and supination (Trinkaus 1983, 1991). The fact that the radial tuberosity is more medially located (Trinkaus 1983) would allow a neanderthal to supinate more powerfully, that is, use his/her biceps to lift, pull, crush or carry objects.

Tibeal tuberosities and femoral muscle attachment areas are similarly very large. This, coupled with large, heavily catilaged knee joints with very thick patellae would give Neanderthal the capability to generate a massive amount of force around the knee area (Trinkaus 1983; Trinkaus and Thompson 1987; Stringer and Gamble 1993). Obviously Neanderthal was traversing rough terrain, jumping and breaking falls.

Furthermore, in cross-sectional analysis of Neanderthal tibiae and femora, we can see that not only are they larger in circumference, but more importantly, they show a considerable thickening of the internal walls (Trinkaus 1983, 1991). Furthermore, while later humans exhibit a tear drop shaped cross section in their femurs, Neanderthal femurs are round in cross section which tells us a great deal about their movements (Trinkaus 1983, 1985; Shreeve 1995). That is, they had to be more sedentary, while those that came after them, were much more likely to have travelled long distances regularly. Neanderthal obviously moved to and fro over rugged landscape, whereas moderns moved longer distances over easeir terrain as evidenced by the tear drop shape of their femur cross sections. this is corroborated by the fact that raw material (lithic) used for Mousterian tools was most often found within 5 km of the site where the tools made from it were discarded, while Aurignacian industries show a much higher proportion of exotic (>5km away) stone being used (Geneste 1988; Shreeve 1995; Mellars 1996).

Finally, palmar tuberosities in the carpal and phalangeal bones, while barely perceptible in modern humans are very apparent and noticeable in Neanderthal. This would have made Neanderthal fingers and thumbs upwards of twice the strength of modern humans Lumely-Woodyear 1973; Trinkaus 1983; Tattersall 1995). Tuberosities of distal phalanges being large and almost circular (Trinkaus 1981, 1983, 1991)indicating that they used their fingertips/nails on a regular basis for a wide variety of tasks such as grasping, pinching and kneading materials. It should also be noted that Neanderthal children were very robust at a very early age and so robusticity can be seen as genetic, and not an immediate environmental factor as some have surmised.

Tibia/femur ratios -

As we can see from Trinkaus' studies into the ratio of Neanderthal tibia and femur length analysis,(Stringer 1995) the Neanderthal mean is close to that of modern Lapp and Inuit populations, pointing towards a cold climate adaptation according to Stringer (1995) and Trinkaus (1981, 1991). While Shreeve (1995)might disagree, as do we, it is certain that their statures were comparatively short and stocky in appearance. Levantine Neanderthals also exhibited this stature, yet lived for tens of thousands of years in relatively warm conditions. It is highly unlikely that they moved from Europe to the Levant to escape the cold if they were cold adapted and to those that would argue that this is true, I would point out that Neanderthal had endured much harsher and colder conditions before their move into the Middle East and therefore must have migrated for some other reason not yet explained or understood.

Pelvic area -

The pelvic region is mentioned if only to put away any misconceptions. Though Trinkaus did not have the advantage of the Kebara 2 skeletal morphlogy in his early study (Trinkaus 1983), there is no doubt that Neanderthal possessed almost identical pelvic regions. Though the pubic ramus is longer and more gracile (Bar-Yosef 1988; Rosenberg 1988; Rak 1990; Stringer and Gamble 1993) there is no indication that this resulted in a different gait, longer gestation periods or different posture. Though the femur seems to be attached at a more outward angle, indicative of squatting perhaps, the significance of these two characteristics is still unclear and poorly understood.

Carpal-metacarpal joint on the thumb -

Trinkaus (1983) has exhaustivelystudied the thumb and found that it would have been much stronger in raw gripping power, but a little less so than moder humans in precision power. The orientation wouldhave made it a little more difficult for a Neanderthal to perhaps touch his/her baby finger, though not by much. In any case, it is not a major difference, though it definitely points to environmental stresses favouring gripping power such as holding onto tools or even animals during a hunt.

Scapula -

Neanderthal scapula have high spines and the acromion is farther away from the axis of rotation (Trinkaus 1983). Mediolaterally they are wide (Debenath and Tournepiche 1992). This coupled with a dorsal as opposed to ventral sulcus (Trinkaus 1983) would give a Neanderthal a powerful upper arm swing. Thus Neanderthals were probably better at throwing (Debenath and Tournepiche 1992) than their modern contemporaries. This would make them better thrusters and could relate to hunting techniques and tool knapping.

Conclusion -

Throughout the body of this paper it has been shown that the post-cranial adaptations in H. neanderthalensis tends mostly towards robusticity. consequences of this are seen as bowing of limbs, slightly different appendicular connections (thumb, femur and humerus). That their post-cranial skeletal morphology differs little, except for its robusticity, should at least be a warning sign for the anti-multiregionalists of Neanderthal evolution such as Gamble, Stringer and Rak.

While their body shape does indicate cold climate adaptation, I do not think that this has been proven beyond a doubt. Trinkaus (1981) may think so, but I think that the evidence supports genetic selection for robusticity as a result of their very hard and marginal existence. That they did not have the culture to protect themselves from the elements, including the cold and instead had to use brute strength to forcibly manifest their survival does not mean cold adaptation. This is an important difference. As well, if their robusticity was not absolutely essential, nature would have moved swiftly to purge it from the species, since it was, biologically, a very expensive adaptation (Stringer and Gamble 1993; Shreeve 1995). Neanderthal, for whatever reason, did not have the technology and therefore developed cultural attributes to live as complex an existence that their humanity and intelligence allowed, so they made up for it with sheer physical prowess. This is what allowed them to live in the cold climes of glacial Europe.