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Pouch Young (pouch + young)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

Survival of very small macropod pouch young followingshort-term isolation from the pouch at various environmental temperatures

ANIMAL CONSERVATION, Issue 4 2002
David A. Taggart
There is considerable interest in the use of assisted breeding techniques as a component of conservation programmes for a variety of macropods threatened with extinction. While cross-fostering is being conducted in some programmes in captivity, little is known about the best techniques for carrying this procedure out from wild populations. In this study we compare the success of various procedures for isolating small tammar wallaby (Macropus eugenii) and brush-tailed rock wallaby (Petrogale penicillata) pouch young (0.4 g,410 g) for short periods (6 hours) as a first step towards establishing a methodology for recruiting endangered macropod pouch young directly from the wild for foster-rearing in captivity. Pouch temperature and humidity were determined. Pouch young from females in experimental groups were weighed, measured and then isolated, at 30°C, 27°C or 23°C, and 100% humidity. After isolation the weight of pouch young maintained at 30°C and 27°C had declined significantly (2,17% of body weight), whereas those held at 23°C and 100% humidity lost less than 0.5% of body weight. All young were reattached to the active teat of their mother following pouch isolation and their survival and growth monitored. Pouch young from the control group and those isolated at 23°C and 100% humidity survived and grew at normal rates. Only the largest pouch young maintained in isolation at either 30°C or 27°C survived to day 7 following reattachment. Data indicated that the proportion of weight lost by pouch young as a result of isolation decreased with increasing size and age of the pouch young. These trials indicate that it would be possible to harvest very small macropod pouch young from a species in the wild with a very high probability that they would survive short-term isolation from the pouch and reattachment to the teat. The use of this procedure in combination with cross-fostering techniques will allow small pouch young from threatened macropod species to be recruited directly from the wild into captivity, for captive breeding or to improve genetic diversity in captive colonies. It should also act to reactivate diapause embryos in these animals and hence may accelerate breeding in wild-based mothers. [source]

Sexual segregation in western grey kangaroos: testing alternative evolutionary hypotheses

JOURNAL OF ZOOLOGY, Issue 2 2007
A. M. MacFarlane
Abstract In sexually dimorphic ungulates, sexual segregation is hypothesized to have evolved because of sex-specific differences in body size and/or reproductive strategies. We tested these alternative hypotheses in kangaroos, which are ecological analogues of ungulates. Kangaroos exhibit a wide range of body sizes, particularly among mature males, and so the effects of body size and sex can be distinguished. We tested predictions derived from these hypotheses by comparing the distribution of three sex,sex size classes of western grey kangaroos Macropus fuliginosus, in different habitats, and the composition of groups of kangaroos, across seasons. In accordance with the predation risk-reproductive strategy hypothesis, during the non-breeding season, females, which were more susceptible to predation than larger males, and were accompanied by vulnerable young-at-foot, were over-represented in secure habitats. Large males, which were essentially immune to predation, occurred more often than expected in nutrient-rich habitat, and small males, which faced competing demands of predator avoidance and feeding, were intermediate between females and large males in their distribution across habitats. During the breeding season, females continued to be over-represented in secure habitats when their newly emerged pouch young were most vulnerable to predation. All males occupied these same habitats to maximize their chances of securing mates. Consistent with the social hypotheses, groups composed of individuals of the same sex, irrespective of body size, were over-represented in the population during the non-breeding season, while during the breeding season all males sought females so that mixed-sex groups predominated. These results indicate that body size and reproductive strategies are both important, yet independent, factors influencing segregation in western grey kangaroos. [source]

Survival of very small macropod pouch young followingshort-term isolation from the pouch at various environmental temperatures

ANIMAL CONSERVATION, Issue 4 2002
David A. Taggart
There is considerable interest in the use of assisted breeding techniques as a component of conservation programmes for a variety of macropods threatened with extinction. While cross-fostering is being conducted in some programmes in captivity, little is known about the best techniques for carrying this procedure out from wild populations. In this study we compare the success of various procedures for isolating small tammar wallaby (Macropus eugenii) and brush-tailed rock wallaby (Petrogale penicillata) pouch young (0.4 g,410 g) for short periods (6 hours) as a first step towards establishing a methodology for recruiting endangered macropod pouch young directly from the wild for foster-rearing in captivity. Pouch temperature and humidity were determined. Pouch young from females in experimental groups were weighed, measured and then isolated, at 30°C, 27°C or 23°C, and 100% humidity. After isolation the weight of pouch young maintained at 30°C and 27°C had declined significantly (2,17% of body weight), whereas those held at 23°C and 100% humidity lost less than 0.5% of body weight. All young were reattached to the active teat of their mother following pouch isolation and their survival and growth monitored. Pouch young from the control group and those isolated at 23°C and 100% humidity survived and grew at normal rates. Only the largest pouch young maintained in isolation at either 30°C or 27°C survived to day 7 following reattachment. Data indicated that the proportion of weight lost by pouch young as a result of isolation decreased with increasing size and age of the pouch young. These trials indicate that it would be possible to harvest very small macropod pouch young from a species in the wild with a very high probability that they would survive short-term isolation from the pouch and reattachment to the teat. The use of this procedure in combination with cross-fostering techniques will allow small pouch young from threatened macropod species to be recruited directly from the wild into captivity, for captive breeding or to improve genetic diversity in captive colonies. It should also act to reactivate diapause embryos in these animals and hence may accelerate breeding in wild-based mothers. [source]