The natural history of nyala, Tragelaphus angasi (Mammalia, Bovidae) in Mozambique. Bulletin of the AMNH ; v. 155, article 4
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Abstract
"We made observations of nyala (Tragelaphus angasi) for more than 2000 man-hours primarily between September, 1971, and April, 1974, in Zinave National park, Mozambique, and vicinity, mostly in a study area of approximately 32 sq. km., near Zinave Camp on the Save River. Data on habitat, climate, measurements, and age and growth of nyala are presented. In the study area 70 percent of the adults seen were females. The population of nyala in the study area increased from an estimated 175 to 250 in 1971 to more than 326 in 1973, for a density of about 10 nyala per sq. km. More than 60 percent of the nyala seen were adults. Nyala were seen alone or in groups up to 30 in number; 67 percent of the observations were of one to three animals. Males were seen alone twice as frequently as females. Nyala groups are not permanent, and individuals come and go. A subadult male was seen in association with at least 15 other individuals and an immature with 16 in eight and 13 days respectively. The strongest bond is probably between a mother and her young, but newborn nyala are left hidden in thickets for several weeks. The home range of male nyala is up to 10 sq. km., and does not change seasonally. The home range of females is approximately the same size. No evidence of territoriality has been observed, and there is extensive overlap of home ranges of males and females. Nyala are active in the daytime especially at temperatures between 20° C. and 30° C. and at night during the rainy season. They shelter from both sun and cold in thickets and at Zinave drink daily. In the dry season when food is less available nyala may wander 12 km. between sunup and sundown. Lions and leopards are the main predators of adult nyala, whereas baboons and raptorial birds are the principal predators of juveniles. Nyala are killed by man for trophies and meat. Nyala have a single offspring born after an eight and one-half month gestation period at any time of the year. Females may conceive within a week after parturition. Nyala are often seen in association with impala or baboons. Nyala eat leaves, fruits, flowers, twigs, and bark of more than a hundred species of plants. They are parasitized by ticks, flies, trypanosomes, and helminths. The social behavior of nyala is shown mainly by male displays and rituals for assertion of dominance without fighting. A hypothesis of the communicatory role of the white markings of nyala is presented"--P. 323.
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Includes bibliographical references (p. 385-386).