Showing papers by "R. J. van Aarde published in 1986"
TL;DR: A tendency towards seasonality in the activity of accessory glands, preceded and accompanied by an increase in circulating plasma testosterone values, may be considered as a factor enforcing seasonal breeding in females.
Abstract: Summary. The reproductive tract of the male Cape porcupine is morphologically and histologically similar to that of New World hystricomorph rodents. Males are reproductively active throughout the year and attained sexual maturity (complete spermatogenesis) at an age of 8-18 months. Testes weight, epididymides weight and seminiferous tubule diameter attained asymptotic values at the age of 23-30 months. A tendency towards seasonality in the activity of accessory glands, preceded and accompanied by an increase in circulating plasma testosterone values, may be con sidered as a factor enforcing seasonal breeding in females. Testosterone conccntrations in pubertal males were significantly higher than those recorded in sexually mature males.
26 citations
TL;DR: The constituent cell types of the ovary of the porcupine were similar to those of New World hystricomorph rodents and accessory corpora lutea and luteal bodies were formed through the luteinization of the membrana granulosa or theca interna of antral follicles.
Abstract: The constituent cell types of the ovary of the porcupine were similar to those of New World hystricomorph rodents and accessory corpora lutea and luteal bodies were formed through the luteinization of the membrana granulosa or theca interna of antral follicles. All luteal bodies were histologically similar. The total volume of luteal tissue per female was not affected by fetal age and was unrelated to circulating concentrations of maternal plasma progesterone. Maternal plasma progesterone concentrations were correlated with fetal age. Follicular activity occurred throughout pregnancy but was not affected by fetal age or related to circulating values of oestradiol-17 beta. The formation of accessory corpora lutea during pregnancy is regarded as important in supplementing progesterone during pregnancy.
19 citations
TL;DR: The paper describes the pedigree of nine King cheetahs born in captivity and provides evidence that the king coat colour pattern in Acinonyx jubatus appears to result from the action of a recessive allele at an autosomal locus.
Abstract: The paper describes the pedigree of nine King cheetahs born in captivity and provides evidence that the king coat colour pattern in Acinonyx jubatus appears to result from the action of a recessive allele at an autosomal locus.
13 citations
TL;DR: In this article, the authors report on the successful relocation of captive-bred male servals and provide information on activity patterns, dispersal and spatial utilization, they are predominantly nocturnal and direction of dispersal was determined by habitat preferences, they confine themselves to areas with permanent water and adequate shelter.
Abstract: Summary
This paper reports on the successful relocation of captive-bred male servals and provides information on activity patterns, dispersal and spatial utilization. Servals maintain themselves without any prior training in hunting. They are predominantly nocturnal and direction of dispersal was determined by habitat preferences, they confine themselves to areas with permanent water and adequate shelter. Core areas of activity coincided with the points of release and home range size varied from 2.1 to 2.7 km2.
Resume
Cet article rend compte du succes de la reimplantation de servals mâles reproduits en captivite et fournit des informations sur les types d'activite, de dispersion et d'occupation spatiale. Les servals survivent sans entrainement prealable a la chasse. Ils sont avant tout nocturnes et le sens de leur dispersion est determine par des preferences d'habitat, se confinant dans des zones a eau permanente et abri suffisant. Les regions centrales de leur activite coincident avec les zones de lâchage et les domaines vitaux varient de 2, l a 2,7 km2.
10 citations
TL;DR: The production of PBPP during pregnancy is considered to be a mechanism which facilitates a reduction in the rate of progesterone metabolism during pregnancy, as in related New World hystricomorph species.
Abstract: Circulating concentrations of progesterone, progesterone-binding plasma proteins (PBPP) and oestradiol-17 beta in pregnant porcupines remained relatively low until Days 25-30 post coitum. Progesterone values peaked (102-180 ng/ml; N = 3) 42-60 days post coitum and the rapid increase in oestradiol-17 beta concentrations approximated that of progesterone with peak values (170-210 pg/ml) being attained 60-85 days post coitum. The pattern of PBPP synthesis, as suggested by circulating concentrations, was closely related to that of plasma progesterone, with values remaining low (less than 20 pmol/ml) until Day 31 post coitum, reaching peak levels at Days 50-56 and Days 73-77 post coitum. The production of PBPP during pregnancy is, as in related New World hystricomorph species, considered to be a mechanism which facilitates a reduction in the rate of progesterone metabolism during pregnancy.
9 citations
TL;DR: Avery, M. I. and Vesey-Fitzgerald, B. (1949).
Abstract: Avery, M. I. (1983). Winter activity ofpipistrelle bats. PhD thesis, University of Aberdeen. Avery, M. I. (1985). Winter activity of pip istre lie bats. J. Anim. Ecol. 54: 721-738. Erkert, H. G. (1982). Ecological aspects of bat activity rhythms. In Ecology ofbats: 201-242. Kunz, T. H. (Ed.). New York: Plenum Press. Stebbings, R. E. (1977). Order Chiroptera: Bats. In Handbook of British mammals: 68-128. Corbet, G. B. & Southern, H. N. (Eds). Oxford: Blackwell Scientific Publications. Vesey-Fitzgerald, B. (1949). British bats. London: Methuen.
3 citations
1 citations