. Advances in the study of mammalian behavior. Mammals. Structure, Development, and Function 135 .4 r UNGULATES. 6 .8 RELATIVE BRAIN SIZE (EQ) Fig. 11. Distributions of encepiialization quotients in various assemblages of ungulates and carnivores. "Archaic" refers to orders that are now extinct: amblypods, condylarths, and creodonts. (From Jerison, 1973; copyright Academic Press, New York.) Very Large Brains: Cetaceans and Hominids In the diversification of tfie mammals, very large-brained species appear in three orders—proboscideans, cetaceans, and primates. The probosci
. Advances in the study of mammalian behavior. Mammals. Structure, Development, and Function 135 .4 r UNGULATES. 6 .8 RELATIVE BRAIN SIZE (EQ) Fig. 11. Distributions of encepiialization quotients in various assemblages of ungulates and carnivores. "Archaic" refers to orders that are now extinct: amblypods, condylarths, and creodonts. (From Jerison, 1973; copyright Academic Press, New York.) Very Large Brains: Cetaceans and Hominids In the diversification of tfie mammals, very large-brained species appear in three orders—proboscideans, cetaceans, and primates. The proboscidean brain size is know^n primarily on the basis of Pleistocene and Recent species, a rather incomplete record. A more complete story can be developed for the other two orders, with evolutionary evidence from an excellent fossil record. The evolution of encephalization in the cetacean brain is pre- sented in Fig. 12, utilizing the method of convex polygons (Jerison, 1978). Paleogene, Neogene, and Recent grades are compared with the archaic mammalian grade shown earlier in Fig. 8 and with the present hominid and pongid grades. There are two points to empha- size. First, as an order, the cetaceans had achieved their present grade of encephalization no later than the Lower Miocene epoch, about 18 million years ago. Second, within the order Cetacea, the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Eisenberg, John Frederick; Kleiman, Devra G; American Society of Mammalogists. [Shippensburg, Pa?] : American Society of Mammalogists
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Keywords: ., bookcentury1900, bookcollectionbiodiversity, booksubjectmammals
