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
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.
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
1 Department of Zoology, Oxford University, South Parks Road, Oxford OX1
2 Ministry of Agriculture, Fisheries and Food, Worplesdon Laboratory,
Guildford, Surrey GU3 3LQ
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.
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
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.
|Journal of Reproduction and Fertility (1978)
|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.