The consequences of differences in litter size for the nursing cat and her kittens

Abstract

Seventy‐one litters of kittens (mean litter size 4.4) were studied from birth to eight weeks of age in order to measure kitten growth and maternal body condition. Few sex differences in growth occur; male and female kittens place a similar burden on their lactating mother. A mother's weight (non‐pregnant, non‐lactating) interacts with litter size to determine the fate of her growing kittens. A large litter places a burden on both the mother and on the kittens, whose growth is affected; small mothers with large litters are particularly at risk. An acceleration in kitten growth occurs at about 32 days as the kittens take more solid food. This change in growth rate is more marked in large litters. Kittens of light mothers and kittens in large litters are weaned at a lower weight, and kittens of light mothers are weaned earlier. Our results indicate that, under poor environmental conditions, large litters would be less successful than small litters; kitten growth and survival would be affected and providing milk for a large litter would have a detrimental effect on the mother's health. The cost of lactation appears to have been a major evolutionary factor in determining mean litter size.

Lactation, maternal behavior and infant growth in common marmoset monkeys ( Callithrix jacchus ): effects of maternal size and litter size

“…The fact that small mothers rearing twins were highly likely to be ill and infertile in the year following lactation, while small mothers rearing singletons were fertile and showed no illness, suggests that the combined effects of maternal and litter size might be an important factor in reproduction allocation in this small primate. This result is similar to that seen in house cats, in which maternal stress (lack of coordination, bedraggled appearance, and poor appetite) was most prevalent in small mothers nursing large litters (Deag et al 1987).…”

“…However, in large-bodied species, such effects are most marked in those taxonomic groups that are capital breeders (Jonsson 1997), who pay the costs of lactation investment by drawing heavily from maternal energy reserves (domestic sheep: Thompson 1983; gray seals: Iverson et al 1993;bighorn sheep: Festa-Bianchet et al 1998) or in species producing large litters (e.g., house cat: Deag et al 1987).…”

Integration of proximate and evolutionary explanation of reproductive strategy: The case of callitrichid primates and implications for human biology

“…This pattern suggests that maternal physiology will protect energy stores more tightly in early events (e.g., placentation) and less so in later events and that behavioral adaptations (e.g., reduced activity) play a large role in maternal management of energetic investment in lactation. Similar results have been reported in other nonhuman primates (see Dufour and Sauther (2002) for a review) and in nonprimates (e.g., cats (Deag et al, 1987)). …”

Changes in the activity of captive cotton-top tamarins (Saguinus oedipus) over the breeding cycle

“…It is possible that the ease with which food could be obtained in captivity minimised weight loss; however, since in the present study feeding time increased beyond this point, a longer-term study may find subsequent weight loss in lactating females. Although there are no comparative data from other primates, increased litter size was associated with a stress syndrome characterized by weakness in female cats studied by DEAG et al (1987): the larger the litter, the more weight the mother lost, although there was no effect of stress on the proportion of a mother's litter that survived.…”