2.5 Polynesian Cold Resistance and Famine Resistance: Houghton’s Evidence
29
Houghton speaks of the value of exercise such as paddling a canoe in sustaining
heat levels:
During such moderate exercise both phenotypes [cold-adapted and non cold-adapted] would
be still in considerable heat imbalance under the conditions defined above of temperature
14.5 ◦ C, 91% humidity and 16 kph wind. The larger body is producing about 62% of the
heat being lost, the smaller body about 53%. However, these conditions can be related
to the realities of canoe existence. During severe wet-cold exposure conditions, progress
under sail would be possible and physical activity for most of the crew restricted; they
would be huddled down out of the wind and protected by whatever (damp) coverings were
available. Heat balance of the large muscular body could be maintained for long periods
by shivering. Smaller individuals would range in condition from chilled to hypothermic or
worse, depending on body size and the time the severe wet wind-chill conditions persisted
(p. 175).
Houghton concludes:
I suggest that, whatever the mean air and water temperature, the environment of Remote
Oceania is effectively the coldest to which Homo sapiens has adapted and, at the time of
Western contact, the people of the region displayed the supreme cold-climate body form.
This influence of environment is pervasive, going beyond simple consideration of infracranial proportions and muscularity to shape the distinctive Polynesian head and dentition
(Houghton and Kean 1987) (p. 174).
Houghton’s study of the evolution of the distinctive form of the Polynesian head
[31] illustrates how complex and extensive the morphological changes consequent
on the evolution of the Polynesian cold-adapted body form were. The need for a
larger airway, needed to supply oxygen to the larger Polynesian muscles, for example, required a greater vertical development of the face. Houghton argues that airway
size
is appropriate to oxygen demand and it follows that the extent to which oxygen demand
varies between individuals at maturity determines the extent to which the face develops vertically. Amongst adults, differences in anterior nasal height as a simple indicator of airway
size are a rough reflection of differing body size, and particularly of differences in muscle
mass, for from this tissue comes the great oxygen demand during activity. . .On the basis
of the preceding discussion, nasal height in large muscular Polynesians ought to be in the
upper range for Homo sapiens, and this proves to be so. For a large global series Howells
(1989) gives a range from 42.76 to 56.91 mm for males and 42.86 to 53.33 mm for females.
Top of the range for each sex are the Siberian Buriats (a most distinctive, inland, continental, cold-climate people). Chatham Island Moriori are next with values of 55.95 and 52.61.
People of Remote Oceania (Hawaii, Guam and Easter Island) take up three of the next
five places in the range, along with the Arikara and the Inuit. For the New Zealand Maori,
Wagner (1937) gives values of 54.3 for male and 51.4 for female, and for Marquesas, 57.4
for males – surpassing the Buriats – and 52.7 for females (p. 108).
Houghton explains that provision for a larger airway required the flattening of
the cranial base:
The cranial base is an interface between two functional regions, for as well as supporting
the brain it also forms the roof of the airway. Berglund (1963) establishes that flattening the
cranial base led to an increase in volume of the nasopharynx and derived a formula for its
calculation:
29
Houghton speaks of the value of exercise such as paddling a canoe in sustaining
heat levels:
During such moderate exercise both phenotypes [cold-adapted and non cold-adapted] would
be still in considerable heat imbalance under the conditions defined above of temperature
14.5 ◦ C, 91% humidity and 16 kph wind. The larger body is producing about 62% of the
heat being lost, the smaller body about 53%. However, these conditions can be related
to the realities of canoe existence. During severe wet-cold exposure conditions, progress
under sail would be possible and physical activity for most of the crew restricted; they
would be huddled down out of the wind and protected by whatever (damp) coverings were
available. Heat balance of the large muscular body could be maintained for long periods
by shivering. Smaller individuals would range in condition from chilled to hypothermic or
worse, depending on body size and the time the severe wet wind-chill conditions persisted
(p. 175).
Houghton concludes:
I suggest that, whatever the mean air and water temperature, the environment of Remote
Oceania is effectively the coldest to which Homo sapiens has adapted and, at the time of
Western contact, the people of the region displayed the supreme cold-climate body form.
This influence of environment is pervasive, going beyond simple consideration of infracranial proportions and muscularity to shape the distinctive Polynesian head and dentition
(Houghton and Kean 1987) (p. 174).
Houghton’s study of the evolution of the distinctive form of the Polynesian head
[31] illustrates how complex and extensive the morphological changes consequent
on the evolution of the Polynesian cold-adapted body form were. The need for a
larger airway, needed to supply oxygen to the larger Polynesian muscles, for example, required a greater vertical development of the face. Houghton argues that airway
size
is appropriate to oxygen demand and it follows that the extent to which oxygen demand
varies between individuals at maturity determines the extent to which the face develops vertically. Amongst adults, differences in anterior nasal height as a simple indicator of airway
size are a rough reflection of differing body size, and particularly of differences in muscle
mass, for from this tissue comes the great oxygen demand during activity. . .On the basis
of the preceding discussion, nasal height in large muscular Polynesians ought to be in the
upper range for Homo sapiens, and this proves to be so. For a large global series Howells
(1989) gives a range from 42.76 to 56.91 mm for males and 42.86 to 53.33 mm for females.
Top of the range for each sex are the Siberian Buriats (a most distinctive, inland, continental, cold-climate people). Chatham Island Moriori are next with values of 55.95 and 52.61.
People of Remote Oceania (Hawaii, Guam and Easter Island) take up three of the next
five places in the range, along with the Arikara and the Inuit. For the New Zealand Maori,
Wagner (1937) gives values of 54.3 for male and 51.4 for female, and for Marquesas, 57.4
for males – surpassing the Buriats – and 52.7 for females (p. 108).
Houghton explains that provision for a larger airway required the flattening of
the cranial base:
The cranial base is an interface between two functional regions, for as well as supporting
the brain it also forms the roof of the airway. Berglund (1963) establishes that flattening the
cranial base led to an increase in volume of the nasopharynx and derived a formula for its
calculation: