in frequency over the next few days, and eventually stops
(McGuire and Novak 1984, 1986).
Despite the apparent independence of precocial off-
spring, mothers significantly influence their physiology and
behavior (Hennessy 2003). For example, many precocial
young start to eat solid food when only a day or two old
and can survive without milk by 1 or 2 weeks, but nursing
frequently continues for several weeks or months (Rood
1972; Kleiman 1972, 1974; Makin and Porter 1984). Moth-
ers of precocial young also continue to groom their off-
spring well beyond the time when such grooming functions
to stimulate urination or defecation (Kleiman 1972, 1974).
The continued association between mothers and young, ex-
emplified by prolonged nursing and grooming, is appar-
ently beneficial to both (Kleiman 1974).Litter size
Mothers spend more time in the nest with small than with
large litters (see table 20.2, column In nest). One explana-234 Chapter Twenty
Table 20.2 Maternal behavior in relation to litter size among selected rodents
Study Total In Age at Groom
Species design carea nest weaning Nurse pup Nest build Attackb Reference
Norway rat (Rattus AS Seitz 1958
norvegicus)
ASS Grota and
Ader 1969;
Ader and
Grota 1970;
Grota 1973
A S S S Leigh and
Hofer 1973
A X X (quality) Fuemm and
Driscoll 1981
House mouse A S S (days 1–14); X X Priestnall
(Mus musculus) L (days 15 –20) 1972
A L Maestripieri
and Alleva
1990
Wild house mouse N S (days L König and
(Mus domesticus)1–4) Markl 1987
Social vole (Micro- N X X X Libhaber and
tus socialis) Eilam 2004
Bank vole (Clethri- A L Jonsson et al.
onomys glareolus) 2002
Deer mouse (Pero- NL Millar 1979
myscus mani-
culatus)
Gerbil (Meriones A S X L S Elwood and
unguiculatus) Broom 1978
Golden hamster A Sc S (quality) Scott 1970
(Mesocricetus
auratus)
A S X Guerra and
Nunes 2001
Desert woodrat N L Cameron
(Neotoma lepida) 1973
Guinea pig (Cavia A & N L Stern and
porcellus) Broner 1970
European ground N L Millesi et al.
squirrel (Spermo- 1999
philus citellus)d
NOTES: Shigher in small litters; Lhigher in large litters; Xno difference with respect to litter size (modified from Mendl [1988: Tables III, IV] and updated with additional
information). Aartificial manipulation of litter size, Nnatural litters. Unless otherwise indicated, studies were conducted in the laboratory and patterns of behavior measured
by duration, frequency of occurrence, or percent of the observation period spent performing the behavior. Empty cells indicate that the behavior was not recorded in the study.a
Rating of maternal quality which included categories such as response to opening of cage, reluctance to leave litter, retrieval of young, and quality of nest (Seitz 1958); sum of
time percentages per observation period for nurse, groom pup, and nest build (König and Markl 1987).b
cAttacks by mother directed at unfamiliar male conspecifics.
dRepresents time spent by mother in bodily contact with young.
Field study; age at weaning assessed by condition of mothers’ teats, not behavioral observations of mothers, and young and yearling females excluded.