Badgers have unusual breeding patterns since mating can take place at any time of the year. After mating, badgers exhibit what is known as delayed implantation. They keep the fertilised eggs, in the womb in a state of suspended development until they implant at the end of December.

Despite the presence of the fertilised eggs, female badgers can have further matings. Not only are mating opportunities maximised, but young can also be born at the best time of year (during early spring so that, after weaning, food for the hungry cubs is becoming more plentiful).

What causes delayed implantation?

It is known that reproductive steroid hormones (progesterone) are taken up by the fatty deposits of badgers during the summer. It is thought that these hormones are released when the fatty deposits are used up in the early winter. A second increase in the levels of these steroids allows the fertilised eggs to implant in December.

Cubs are usually born during the first fortnight in February in the south and west, but sometimes a little later as you go further north in the UK.

New-born badger cubs are covered in grey silky hairs and usually the dark facial stripes are already visible. New cubs are about 12cm long (plus a 3-4cm tail), weigh about 75-130g and their eyes are closed for about 5 weeks.Badger cubs are fed on their mothers milk, and often live within a special nursery chamber within the sett. Their waste products are removed from the nesting chamber by the sow, until such time as they are mobile enough to use the latrines outside the sett.

Weaning usually begins when the cubs are at least three months old. During this time they feed on some solid food, particularly earthworms, and follow the mother when she goes off to feed herself.

Sense of smell is the most important sense for badger cubs, since the first two months or more of their lives are spent in darkness below ground where smell, hearing and touch are far more useful than sight. Even at three months old, the cubs are still very short-sighted. By following the example of their parents they also learn to use the "latrines" sited near the sett.

Dry, clean bedding is of great importance for the survival of the cubs. A chamber full of hay, straw and bracken acts as an efficient heat insulator, helping the cubs conserve their body heat. The straw will prevent the cubs being too battered by cold draughts; and it will insulate their little bodies from the cold soil underneath where they lie down.

Academic Note:

Journal of Zoology Journal of Zoology Volume 218 Issue 4, Pages 587 - 595

Social structure of the Eurasian badger (Meles meles): genetic evidence

P. G. H. EVANS 1 , D. W. MACDONALD 1 C. L. CHEESEMAN 2
1 Department of Zoology, Oxford University, South Parks Road, Oxford OX1 3PS
2 Ministry of Agriculture, Fisheries and Food, Worplesdon Laboratory, Guildford, Surrey GU3 3LQ

ABSTRACT

Studies of territorial, highly stable groups of wild Eurasian badger, Meles meles, revealed that more than one adult of each sex may breed within a group, and that extra-territorial movements may occur within clusters of territories. Although there is some genetic structuring within a local population and a deficiency of heterozygotes, due probably to minimal juvenile dispersal, heterogeneity of gene frequencies is reduced by: (a) adults transferring between adjacent groups, and (b) matings between males of one group and females of another. Marked changes in gene frequencies between generations indicate that a minority of males have a strong influence on the genotypes of the offspring, being either polygynous or promiscuous. Within one generation, the young of a given group may be sired by two or more males, and these males may not necessarily be members of that group.

Academic Note:

Journal of Zoology Volume 242 Issue 4, Pages 705 - 728 - Accepted 30 September 1996

The demography of a high-density badger (Meles meles) population in the west of England

L. M. Rogers 1 , C. L. Cheeseman 1 , P. J. Mallinson 1 and R. Clifton-Hadley 2 1 Central Science Laboratory, Ministry of Agriculture, Fisheries and Food, Sand Hutton, York, YO4 1LW 2 Veterinary Laboratories Agency, New Haw, Addlestone, Surrey, KT15 3NB

Copyright 1997 The Zoological Society of London ABSTRACT

Data from the longest running capture-mark-recapture study of Eurasian badgers, in an undisturbed wild population at Woodchester Park in Gloucestershire, were used to investigate population dynamics. Twenty-one social groups of badgers occupying an area of 7.3km2 were studied from 1978-1993. The density increased steadily over the study period, reaching the highest published density known anywhere at 25.3 adults per km2 in 1993, and the average social group size increased to 8.8 adults (S.E. ± 0.85) in 1993. By 1993, 97% of the population trapped was of known age and overall the population consisted of 27% cubs and 73% adults. In addition, the results supported previous studies in that the population had an equal sex ratio as cubs, but became increasingly female biased with age. There was high juvenile mortality, nearly 50% dying in their first year. Between 58 and 90.2% of adult females did not breed each year.

Academic Note:

Journal of Reproduction and Fertility (1978) 52 55-58

Plasma progesterone levels during delayed implantation in the European badger (Meles meles)

M. Bonnin, R. Canivenc and Cl. Ribes showed that there was a biphasic pattern of progesterone secretion during the year. Delayed implantation was characterized by low concentrations from February to June, a significant increase during July, August and September, and a return to low levels in October–November. A second significant increase was observed in December and early January just before the presumed time of implantation.