Suckling and Weaning in Captive White-Tailed and Fallow Deer

Abstract

Parental investment and parent-offspring conflict theories make specific predictions on the behavior of parents and offspring. Since milk is a direct and vital form of maternal investment in mammals, nursing behavior is very well suited to test such predictions. We provide such tests here, as well as a fine-grained quantitative description of the weaning process in two species of deer. Both in white-tailed and fallow deer, fawns of primiparas had a significantly higher suckling rate than those of multiparous mothers in the first few days of life (2.90 ± 0.70 vs 1.24 ± 0.21 suckles/h from 0 to 5 days in FD, p < 0.01; and 1.42 ± 0.22 vs 0.81 ± 0.08 suckles/h from 6 to 10 days in WTD, p < 0.01). In both species, in the first 10 days of lactation, suckling bouts initiated by the mother had a significantly longer mean duration than those initiated by the fawn. We found no inter-sex difference in the rate of suckling, mean duration of suckles, total time suckling (s/h), and proportion of suckling attempts that were successful, in fawns of both species, at any age from birth to 80 days. White-tailed deer single fawns were identical to twins for all the above parameters. Fallow deer mothers were much more aggressive toward alien fawns than white-tailed deer mothers were, and spent more time close to their fawns (less than 10 m, 38% of the time from birth to 80 days, compared to 12% for white-tailed deer). We propose that weaning starts at about 20 days of age in both species. This is the time when the mother terminates more than half of all suckling bouts, terminates more bouts than she initiates, and when suckles are shorter when she initiates compared to when it is her fawn that does.

Nursing parameters in captive killer whales (Orcinus orca)

“…In terrestrial mammals, researchers have documented similar decreases in nursing frequencies and duration with respect to age [Clutton-Brock et al, 1982 in red deer (Cervus elaphus); Gauthier and Barrette, 1985 in bighorn sheep (Ovis canadensis) and fallow deer (Dama dama); Byers and Moodie, 1990 in pronghorn (Antilocarpa americana); Birgersson and Ekvall, 1994 in fallow deer (Dama dama)]. There is some question as to the reasons behind the decrease in suckling time (cumulative/ day) seen in these animals and odontocetes.…”

“…Other studies documented a greater volume of milk received by males during suckling [Reiter et al, 1978 in northern elephant seals (Mirounga angustirostris), Clutton-Brock et al, 1982, Duncan et al, 1984 in horses (Equus caballus), Lee and Moss, 1986 in African elephants (Loxodonta africana)]. However, Gauthier and Barrette [1985] (white-tailed deer [Odocoileus virginianus], fallow deer) and Festa-Bianchet [1988, bighorn sheep] reported no differences in the amount of milk consumed by males and females. Until we can gather quantitative and qualitative information about milk transfer, we can only make inferences about the patterns observed.…”

Inter-Specific Differences in the Structure and Mechanics but not the Chemical Composition of Antlers in Three Deer Species

“…This highlights that only standardized studies under controlled conditions can reliably demonstrate inter-specific differences in antler properties. In particular, zoos keeping various deer species under the same living conditions and management provide excellent material for such inter-specific studies (Gauthier & Barrette 1985, Ralls et al 1986, Pluháček et al 2012.…”

Sex-Biased Parent-Offspring Conflict

“…If not artificially terminated, weaning takes place between four and six months (HERSHER et al, 1963;ARNOLD et al, 1979) but, as in other ungulates (GAUTHIER & BARRETTE, 1985), manifestations of parent-offspring conflict may begin much earlier. Specifically, the period around the fourth week of lamb age seems to be especially critical.…”