Seasonality of reproduction in the European badger Meles meles in south‐west England

Abstract

The reproductive cycle of male and female badgers in the south‐west of England was studied by post‐mortem examination of 1875 badgers collected in 1973–80. The sample was obtained by several methods and showed that animals obtained as road casualties were not representative of the total population samples. Active spermatogenesis was present throughout the year, and in some males aged 8–9 months. A few females first ovulated as yearlings but most primiparous females were adults. Births were in general confined to the early part of the year, but ovulations and matings also occurred at other times. Almost all (97%) adult females possessed corpora lutea. Unimplanted blastocysts were found in females for 11 months of the year (over 80% of adult females in July‐November). Implanted embryos were found in only 32% of adults in January and February: the number of blastocysts per female and the number of implanted embryos per female were not significantly different, indicating that sows implanted all blastocysts or none. Foetal mortality was 36% and post‐natal losses were estimated at 42% from the proportion of lactating females.

Female Receptiveity, Embryonic Diapause, and Superfetation in the European Badger (Meles Meles: Implications for the Reproductive Tactics of Males and Females

“…However, the average number of corpora lutea increases during the same period ( Figure 6) (Neal and Harrison 1958;Ahnlund 1980;Page et al 1994). Furthermore, direct comparison between these two figures, based on the same females, shows that in general there are more corpora lutea than blastocysts, as highlighted in extreme cases where more than ten corpora lutea, but no blastocysts, were observed (Neal and Harrison 1958;Ahnlund 1980;Page et al 1994). However, small blastocysts, formed just before examination, may have been missed during dissection, which may account for the large difference observed between the number of corpora lutea and blastocysts in March (Figure 6).…”

“…Throughout embryonic diapause, the average number of blastocysts per female is fairly constant (Figure 6;Creswell et al 1992;Page et al 1994). However, the average number of corpora lutea increases during the same period ( Figure 6) (Neal and Harrison 1958;Ahnlund 1980;Page et al 1994).…”

“…Since the classic work of Neal and Harrison (1958), based on about 85 animals from southern England, post mortem studies of the reproductive biology of free-ranging badgers include: Canivenc and Bonnin-Laffargue (1963: about 600 from France), Canivenc (1966: about 700 from France), Ahnlund (1980: 1095 from central Sweden), Wandeler and Graf (1982: 230 from Switzerland), Cresswell et al (1992: 650 from southern England, U.K.), Whelan and Hayden (1993: 548 from central Republic of Ireland), and Page et al (1994: 1875 from southern England).…”

“…Seasonal changes in the wet weight of testes combined with epididymides, and the presence or absence of spermatozoa in the caput epididymis, of males suggest that testicular activity in southern England is, on average, highest during late winter to summer and lowest during late autumn to early winter (Figure 1) (Neal and Harrison 1958;Page et al 1994;Neal and Cheeseman 1996). There are always some males that are physiologically capable of reproduction at any time of the year, however, and this capability has been confirmed in vivo in Wytham Woods, Oxford, southern England (Woodroffe and Macdonald 1995b).…”

“…However, as one may speculate from Figure 2, it is possible that throughout most of the year some females are always physiologically receptive to Volume 81 THE QUARTERLY REVIEW OF BIOLOGY mating. Nevertheless, the majority of females are pregnant by early summer (April to June) in southern England, as well as in central Sweden and in Switzerland (Figure 3) (Ahnlund 1980;Wandeler and Graf 1982;Cresswell et al 1992;Whelan and Hayden 1993;Page et al 1994). Unfortunately, conducting yearround behavioral observations of badgers is very difficult even at the setts because they are a nocturnal species that spend much of their time underground.…”