Variability in apparatus, solvent type, and extraction time for lipid extractions is common in the literature. To investigate the effect of this methodological variability on the amount and type of material extracted, equal subsamples of snow goose (Chen caerulescens) homogenate were extracted in Soxhlet and Goldfisch fat extractors with petroleum ether, diethyl ether, chloroform–methanol, and a petroleum ether–chloroform–methanol mixture for 3, 6, 12, and 24 h. The type of solvent used had the largest effect on the amount of material that was extracted. Petroleum ether and diethyl ether extracted few nonlipids, but chloroform–methanol extracted relatively large amounts of nonlipids. We conclude that chloroform–methanol, when used in a Goldfisch or Soxhlet fat extractor, is an inappropriate solvent for studies dealing with body composition.

We review the literature on the relation between whole brain size and general mental ability (GMA) both within and between species. Among humans, in 28 samples using brain imaging techniques, the mean brain size/GMA correlation is 0.40 (N = 1,389; p < 10 −10 ); in 59 samples using external head size measures it is 0.20 (N = 63,405; p < 10 −10 ). In 6 samples using the method of correlated vectors to distill g, the general factor of mental ability, the mean r is 0.63. We also describe the brain size/GMA correlations with age, socioeconomic position, sex, and ancestral population groups, which also provide information about brain-behavior relationships. Finally, we examine brain size and mental ability from an evolutionary and behavior genetic perspective.

Morphology, diets, and activity budgets of four co—existing sea ducks, Harlequin Ducks, (Histrionicus histrionicus), Oldsquaws (Clangula hyemalis), Black Scoters (Melanitta nigra), and Common Eiders (Somateria mollissima), were studied during the fall and winter of 1983—1984 at Cape St. Mary's, Newfoundland. The diets and behavior of these species were related to body size. The smaller species, H. histrionicus and C. hyemalis, had diets with higher energy densities and spent more time feeding than did the larger M. nigra and S. mollissima. Multiple regression models were used to determine how the proportion of time spent feeding varied with five environmental and two temporal variables; we found that the two smaller species showed little flexibility in adjusting their activity budgets. This could become critical to survival of these diurnal feeders during periods of severe winter weather or ice conditions. As suggested by Bergmann in 1847, closely related species, such as these syntopic sea ducks in a harsh marine environment, adjust their behavior and diets to compensate for the thermodynamic differences associated with body size.

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Using data from magnetic resonance imaging (MRI), autopsy, endocranial measurements, and other techniques, we show that (1) brain size is correlated with cognitive ability about .44 using MRI; (2) brain size varies by age, sex, social class, and race; and (3) cognitive ability varies by age, sex, social class, and race. Brain size and cognitive ability show a curvilinear relation with age, increasing to young adulthood and then decreasing; increasing from women to men; increasing with socioeconomic status; and increasing from Africans to Europeans to Asians. Although only further research can determine if such correlations represent cause and effect, it is clear that the direction of the brain-size/cognitive-ability relationships described by Paul Broca (1824-1880), Francis Galton (1822-1911), and other nineteenth-century visionaries is true, and that the null hypothesis of no relation, strongly advocated over the last half century, is false.