Opossums DIDELPHIMORPHIA DIDELPHIDAE VIRGINIA OPOSSUM Didelphis virginiana Kerr Opossums, as a group, are among the oldest, most primitive mammals of the New World. Some scientists call them "living fossils" because they have survived relatively unchanged for at least 50 million years. They are intermediate in many respects between the most primitive of all mammals, the egg-laying monotremes of Australia, and the higher placental mammals. Their chief character is the marsupium or pouch that develops on the abdomen of females. One species occurs in Texas. Description A mammal about the size of a terrier dog, with long, scaly, prehensile tail; short, black, leathery ears; long, slender snout; five toes on each foot, the 'big toe" on hind foot lacking a claw, thumblike and opposable; soles naked; pouch for young developed during breeding season on abdomen of female; pelage of long guard hairs and short soft underfur; two color phases - (1) grayish and (2) blackish; basal fourth or more of tail black, terminal section whitish; legs and feet blackish, toes often white or whitish. Dental formula: 1 5/4, C 1/1, Pm 3/3, M 4/4 X 2 = 50. External measurements of males average: total length, 782 mm; tail, 324 mm; hind foot, 66 mm; of females, 710-320-63. Weight, 1.8-4.5 kg; males are usually larger and heavier than females. Distribution Occurs statewide except for xeric areas of the Trans-Pecos and Llano Estacado of the Panhandle. | |
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