The Number of Young Present in Sequential Litters of the Marsupial Bandicoot, Isoodon macrourus, in Captivity

1984 ◽  
Vol 32 (5) ◽  
pp. 623 ◽  
Author(s):  
RT Gemmell ◽  
MT Walker ◽  
G Johnston ◽  
G Cepon

Twenty adult female bandicoots, Isoodon macrourus, housed in outside enclosures, were examined weekly and the number, sex and teat position of young were recorded throughout 1982. Thirty-nine litters were monitored throughout lactation. The number of young declined from 107 early in lactation to 73 at weaning. Loss of young from the pouch (n = 19) was more pronounced during the colder months of the year. This reduction in litter size may enable the bandicoots to produce some young in unfavourable conditions and thus extend their breeding season.

1984 ◽  
Vol 11 (1) ◽  
pp. 21 ◽  
Author(s):  
JC Merchant ◽  
K Newgrain ◽  
B Green

The growth and development, from 10 to 270 days old, of eastern quolls in a captive colony was recorded. Young were able to detach from the teat by 65 days of age and their eyes were open by 80 days. Statistically significant differences in some measurements from males and females were found as early as 85 days of age. The weaning period commenced at 102 days ofage, and coincided with eruption ofthe first molar teeth. Total independence, determined by the cessation of lactation in the mother, was as early as 142 days in litters of one or as late as 200 days in larger litters. There was a high correlation between litter size and age at independence. Lactation was maintained in all previously suckled mammary glands of adult females after the death of young aged 65 days or over if some siblings remained. This was due to the ability of young of this age to detach and reattach to the teats at will. The implication of this observation is that the commonly held view that the numbers of surviving young in marsupial litters corresponds to the number of lactating teats in the adult female may not always be correct.


1959 ◽  
Vol 37 (5) ◽  
pp. 627-631 ◽  
Author(s):  
J. K. Reynolds ◽  
R. H. Stinson

Certain aspects of the reproductive biology and growth of the European hare, Lepus europaeus hybridus Desmarest, were studied in 1949–52 in southwestern Ontario. The breeding season began in January and declined in August, reaching its height between the second week of February and the third week of June when all females examined were pregnant. The litter size varied from one to four; an average of 1.6 foetuses occurred in the early litters (January–March) and 3.8 in later litters (April–June). One young raised in captivity grew to adult weight (4100 g) in 6 months.


2003 ◽  
Vol 2003 ◽  
pp. 82-82
Author(s):  
F. Forcada ◽  
J.A. Abecia ◽  
J.A. Valares

The efficacy of melatonin implants inserted around the spring equinox to improve fertility and ovulation rate or litter size in Mediterranean ewes has been previously reported (Chemineau et al., 1996; Forcada et al., 2002a.), indicating the ability of the hormone to regulate the hypothalamic activity (Viguié et al., 1995). Moreover, a direct effect of melatonin on corpora lutea and embryonic development has been also reported (Wallace et al., 1988; Abecia et al., 2002). The use of prolific Rasa Aragonesa (RA) ewes (a Mediterranean breed) before culling as embryo donors has been previously tested in the breeding season (Forcada et al., 2002b.). The aim of this experiment was to improve embryo production during the seasonal anoestrus period in selected superovulated RA ewes at the end of their reproductive lives through the use of melatonin.


2007 ◽  
Vol 29 (2) ◽  
pp. 169 ◽  
Author(s):  
D.I. Shevill ◽  
C.N. Johnson

A population of the rufous spiny bandicoot Echymipera rufescens australis was studied for 14 months by live-trapping, and diets were determined by faecal analysis. The population had a high density (approximately 48 individuals on a trapping grid of 2.25 ha). A wide variety of foods were eaten, but fruits and seeds contributed the largest proportion of material to faeces, followed by invertebrates, fungi and dicot plants. Echymipera rufescens may potentially be a significant seed disperser for some plants, such as Pandanus zea. There was a short breeding season, with births occurring between December and March. Females produced one or two litters per year. Mean litter size was just under three, and litter size increased with the mother?s mass. Females produced a mean of 4.9 young per year. We conclude that although E. rufescens is a ?typical? bandicoot in that it is omnivorous and has high fecundity, it is more frugivorous and has a somewhat lower reproductive rate than other Australian bandicoots.


2018 ◽  
Vol 7 (1) ◽  
pp. 81-85
Author(s):  
Md Abraharul Islam ◽  
Monirujjaman ◽  
Rasel Ahammed ◽  
Mahruma Aktar

Abstract not availableJahangirnagar University J. Biol. Sci. 7(1): 81-85, 2018 (June)


1965 ◽  
Vol 43 (3) ◽  
pp. 475-487 ◽  
Author(s):  
E. O. Höhn ◽  
A. K. Sarkar ◽  
A. Dzubin

Mallards and domestic ducks are conspecific. Relative adrenal weight is similar in newly hatched mallards and domestic ducks. Immature mallards have higher relative adrenal weights than domestic ducks of similar age. Adult female mallards also have higher relative adrenal weights and a higher proportion of cortex in the adrenal than adult female domestic ducks, but adult males of the two strains fail to show these differences.Adrenal weight is related to testicular weight in mallards and domestic ducks, but no correlation is evident between adrenal weight and weight of the ovary and oviduct in mallards. Mallards show no adrenal weight sex differences at any of the three ages sampled. A seasonal adrenal weight cycle is apparent in both sexes of the mallard with a weight increase related to the breeding season and another increase during the autumn and winter.The higher relative adrenal weights of (immature and adult female) mallards compared to those of domestic ducks are attributed to the mallards' greater exposure to stress. It is suggested that this effect operates also in adult male mallards but is obscured in the comparison with adult male domestic ducks because in the latter, which have much higher testicular weights, another factor responsible for the correlation between adrenal and testicular weight as noted above makes for increased adrenal weights.


2001 ◽  
Vol 79 (11) ◽  
pp. 2101-2108 ◽  
Author(s):  
Carol I Stefan ◽  
Charles J Krebs

Reproductive output was estimated for a cyclic population of snowshoe hares (Lepus americanus) in the Kluane Lake region of the southwest Yukon Territory. Data collected by five researchers were collated over 8 years (1989–1996). Pregnant hares were captured and held in cages until they gave birth so that reproductive characteristics could be measured. Pregnancy rate, litter size, and neonate size fluctuated significantly throughout the cycle, changes occurring about 2 years before corresponding changes in density. Pregnancy rates were nearly 100% early in the breeding season, but declined up to 20% in the last gestation periods of the year. The number of litters produced in a breeding season varied between two (decline phase) and four (low, early increase phase). Litter size varied among years as well as among litters within a year, larger litters being born later in the breeding season. The body mass and size of newborn hares varied by 5–33% among years. The combined changes in pregnancy rate and litter size resulted in a cyclic change in total reproductive output ranging from a low of 6.9 young per female during the decline phase to a maximum of 18.9 during the second year of the low and early increase phases.


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