Translator Disclaimer
1 June 2002 Relationship between calving time and physical condition in three wild reindeer Rangifer tarandus populations in southern Norway
Author Affiliations +

Time of calving in reindeer Rangifer tarandus varies between populations, but takes place around the start of the green season to ensure a stable food supply for doe and calf. Causes of variation in calving time was investigated by studying the three adjacent populations of North Ottadalen, South Ottadalen and Snøhetta, in Norway. The peak calving time was 12–14 May during 1996–1998 in North Ottadalen, 10 May in 1997 and 11 May in 1998 in South Ottadalen, and 22–26 May during 1996–1998 in Snøhetta. Comparing these results with recordings from 1969–1972, 1978 and 1985, peak calving time has been delayed by 6–8 days in North Ottadalen, and has advanced by 2–6 days in Snøhetta. In South Ottadalen, the peak calving time has remained almost constant. Analyses of covariance showed that calving time was negatively related to autumn dressed weight (P < 0.05), but not to mandible length (P = 0.15), and that calving happened later in Snøhetta than in North Ottadalen for the same level of autumn dressed weight (P < 0.05; 11.5 days) and mandible length (P < 0.05; 14 days). These results strengthen the hypothesis that delayed conception and calving is a consequence of relatively poor doe condition in autumn.

Peak calving time, i.e. the day when 50% of the pregnant does in a population have given birth, has been found to vary between 6 and 27 May in the various populations of wild reindeer Rangifer tarandus tarandus in Norway (Holthe 1975, Reimers 1983a, Reimers 1997, Skogland 1984). Reimers (1983a,b) suggested that female reindeer do not ovulate until they have reached a certain body mass or body composition in autumn. Differences among populations in time of calving may be influenced by different pre-rut body weights and body compositions (Reimers 1983a, Lenvik 1988), different pasture availability during winter influencing the length of gestation (Bergerud 1975), different sex ratios, with large bucks initiating earlier ovulation (Holthe 1975, Verme, Ozoga & Nellist 1986), or genetically fixed adaptations to different start dates of the growing season (Skogland 1989). We examined the above-mentioned hypotheses by comparing three populations in southern Norway: North Ottadalen, South Ottadalen and Snøhetta, for five specific periods covering 28 years.

North Ottadalen (2,700 km2), South Ottadalen (1,500 km2) and Snøhetta (3,295 km2) are adjacent geographical areas located at 61°30-62°35N, 7°15-9°30E in southern Norway. Habitat types and climate are similar in the three areas, with alpine terrain at altitudes of 1,000–1,500 m a.s.l. Wild reindeer populations in the three areas are controlled by hunting. In North Ottadalen, and especially in Snøhetta, the population densities have varied greatly due to varying management policies (Fig. 1). High densities in the 1960s caused severely overgrazed winter pastures in Snøhetta (Gaare 1968), resulting in small reindeer with low body mass (Reimers 1968). Concurrently, the small but growing reindeer population in North Ottadalen (Reimers 1972) enjoyed good pastures and had high body weights. During the last 25 years, the situation was reversed; body weights and winter pasture for the Snøhetta reindeer had improved (Strand, Jordhøy & Holmstrøm 1996), whereas they had deteriorated in North Ottadalen (Reimers & Sørumgård 1995). In South Ottadalen, the population has remained at 300–400 animals, with no apparent changes in pasture quality or physical condition for the last 30 years (K. Granum, pers. comm.).


Calving time in the three herds was determined for the following years: 1969–1972 (Holthe 1975), 1978, 1985, and 1996–1998. Calving data were acquired by calculating the cumulative proportion of births in consecutive days by counting ‘does that have given birth’ and ‘pregnant does’. Two methods were tested:

  1. The doe was classified as a ‘doe that had given birth’ if she had a calf in her vicinity, and as a ‘pregnant doe’ if she had antlers and no calf. Factors that bias such estimates are calf mortality in the first hours/days after birth, barren does with antlers, and pregnant does without antlers.

  2. The newborn/female ratio for a day at the end of a calving season was used as an estimate for the proportion of breeding females (Caughley & Caughley 1974). For each counting day the total number of females was multiplied by this proportion to give the number of breeding females. The cumulative proportion of births was newborns/breeding females. Calf mortality causes bias in this method as the proportion of dead calves increases with time.

We compared the two methods mathematically, using estimated proportions of barren does with antlers and pregnant does without antlers at the start of the calving season (Espmark 1971), and calf mortality during the calving season (Aarthun Ims 1996). We found method 1 to be less biased, and thus only used method 1 in this study. Holthe (1975) used the same sampling method when estimating calving time for the years 1969–1972 in North Ottadalen, South Ottadalen and Snøhetta.

Figure 1.

Approximate number of reindeer during winter in Snøhetta and North Ottadalen from 1930 until 1997. The wild reindeer population in North Ottadalen was established in 1964 (Reimers 1972). The curves are based on data from Hansen (1987), Jordhøy (1994), Jordhøy, Strand, Skogland, Gaare & Holmstrøm (1996), Hageland (1987), Heitkøtter (1981), Reimers (1968), Reimers & Sørumgård (1995), and K. Granum (unpubl. data).

For 1996, 1997 and 1998, we used probit analysis with a significance level of 0.05 when estimating the calving time from cumulative birth proportions (Finney 1971, SAS 6.11). For 1978, 1985 and South Ottadalen 1997, the calving time was estimated qualitatively based on confidence intervals for the cumulative birth proportions because the number of counting days were too low to do a probit analysis.

Table 1.

Mean reindeer calving time (Julian date) for the three Norwegian study populations, with 95% confidence intervals given in parentheses. Data are from the present study and Holthe (1976)a and E. Reimers (unpubl. data)b.

Table 2.

Mean snow depth (in cm) in the period 1 March-15 May for the three Norwegian study areas during the years 1969–1972, 1978, 1985 and 1996–1998. The first column (Mean) shows the overall mean for the period 1967–1999. Data are from the Norwegian Meteorological Institute's observational stations in Lesjaskog (North Ottadalen), Grov (South Ottadalen) and Ångårdsvatnet (Snøhetta).

The physical condition in autumn was measured as dressed weight and mandible length for does ≥2 years old (Reimers 1968). Physical condition estimates with 95% confidence intervals are given for the years preceding the years for which estimates of calving time exist. Data are lacking for some years. The relationship between calving time and autumn dressed weight, and calving time and autumn mandible length was calculated by analyses of covariance with two groups, North Ottadalen and Snøhetta, and a significance level of 0.05 (S-PLUS 2000). South Ottadalen was not included in the analyses due to low sample size.

Snow depths during late winter (1 March -15 May) were registered at meteorological stations in Lesjaskog (North Ottadalen), Ångårdsvatnet (Snøhetta), and Grov (South Ottadalen), located in valleys adjacent to the reindeer areas. We tested for correlations between snow depth and time of calving in the different populations.

Table 3.

Mean reindeer autumn dressed weight and mandible length for the three Norwegian study population with 95% confidence intervals for does ≥2 years old. Data are from E. Reimers (unpubl. data)a, K. Granum (unpubl. data)b, Jordhøy et al. (1996)c and P. Jordhøy (unpubl. data)d.


In the period from 1970 until 1996–1998, the estimated calving time had been delayed by about six days in North Ottadalen, had advanced by about four days in Snøhetta, and had remained almost unchanged in South Ottadalen (Table 1). The changes in Snøhetta and North Ottadalen are probably significant, but unfortunately, Holthe's (1975) data were not available for treatment. Calving time in Snøhetta was significantly later than in North Ottadalen and South Ottadalen for all testable years. In 1998, calving time in North Ottadalen was significantly later than in South Ottadalen, reversing the situation in 1970. In Snøhetta, calving time was significantly later in 1997 than in 1996 and 1998. This coincided with large amounts of snow during late winter 1997 in Snøhetta (Table 2).

From around 1970 until 1995–1997, dressed weights and mandible lengths for does ≥2 years old increased significantly in Snøhetta by 2.6–2.9 kg and 4.4–8.0 mm, respectively, decreased significantly in North Ottadalen by 7.9–8.4 kg and 1.8 mm, respectively, and decreased in South Ottadalen by 2.6–4.9 kg (Table 3). For the years 1995–1997, only small differences in body weight among the populations was recorded (see Table 3).

Analysis of covariance showed a significant negative linear relationship between calving time and autumn dressed weight (y = -0.75x, P = 0.0009), with a significantly later calving of 11.5 days in Snøhetta than in North Ottadalen for the same level of the covariate (P< 10 4; Fig. 2). For mandible length the negative linear relationship with calving time was non-significant (y = -0.46x, P = 0.15), but calving in Snøhetta was significantly 14 days later than in North Ottadalen for the same level of the covariate (P = 0.0007; Fig. 3).

Figure 2.

A significant linear relationship exists between calving time (Julian date) and autumn dressed weight (in kg) for does ≥2 years old (y = -0.75x, P=0.0009), with a different level of 11.5 days for the two populations in Snøhetta and North Ottadalen (P< 10-4). Ancova, R2 = 0.96, P = 1.5*10-7. Data are from 1969–1998.

In Snøhetta, there was more snow in 1997 than in 1996 or 1998 (see Table 2) which agreed with our observations in the mountains during fieldwork. The tendency was clearest in Snøhetta, where pasture availability in May 1997 was low due to exceptionally large snowfalls in late April. For the whole data set, there were no significant correlations between snow depth and time of calving in the different populations.

Figure 3.

A non-significant linear relationship exists between calving time and mandible length for reindeer does a2 years old (y = -0.46x, P = 0.15), with a different level of 14 days for the two populations in Snøhetta and North Ottadalen (P = 0.0007). Ancova, R2 = 0.93, P = 2,7*10-5. Data are from 1969–1998.


The negative relationship between autumn dressed weight and peak calving time suggests that breeding is delayed and/or gestation is prolonged when the physical condition of females is reduced, and vice versa when female physical condition improves. The insignificance of the negative relationship between mandible length and calving time may be explained by the combined effect of 1) higher growth priority of skeletal tissue, in particular in the body extremities and hence the mandible, than in muscular and adipose tissues (Langvatn 1977), and 2) fixed mandible length at 3–4 years of age (Reimers 1968).

For female reindeer, it would be adaptive to delay oestrus and conception until energy reserves are adequate to ensure successful gestation and early lactation. Lenvik (1988) found a negative relationship between autumn dressed weight and conception time among three populations of domestic reindeer, and Reimers (1997) found a negative relationship between autumn dressed weight and calving time for 11 populations of wild reindeer. In the experimental reindeer herd in Kaamanen, Finland, Eloranta & Nieminen (1986) reported that females calving before the peak of the calving period were significantly older and heavier than those calving after the peak. Except for Lenvik (1988), neither of the other two studies provided information on conception dates, and hence, could not exclude differences in pregnancy duration.

Studies on close phylogenetic species support the existence of a relationship between autumn physical condition and time of conception. In a study of two red deer Cervus elaphus populations in Scotland, Mitchell & Lincoln (1973) found a negative correlation between a kidney fat index and the date of conception. Correspondingly, Hamilton & Blaxter (1980) reported a distinct tendency for the heavier red deer hinds within an age cohort and a year to calve about one day earlier for every 4 kg of additional weight. Haagenrud & Markgren (1974) found a negative correlation between condition (measured by mandible length) and time of oestrus in moose Alces alces. In white-tailed deer Odocoileus vir-ginianus, Verme (1965) found that extremely poor nutrition from October through the latter part of November resulted in a delayed and protracted rut. When offered a higher feed level in the treatment group, Verme (1969) found no difference from normal breeding time. In a food manipulation experiment on Scottish blackface ewes Ovis aries, the time of oestrus was delayed in the group of ewes that were in poor condition (Gunn & Doney 1975). In contrast, Dauphiné & McClure (1974) found that condition (weight and fat deposits) did not significantly influence the time of conception in Canadian barren ground caribou Rangifer tarandus groenlandicus. In conclusion, it appears that female oestrus, and thus breeding time, may be influenced by pre-rut physical condition.

Differences in length of gestation could affect the time of calving. Estimates of gestation length in reindeer differ from 192 to 246 days (Skjenneberg & Slagsvold 1968). Autumn body weights of females were similar in Snøhetta in 1995, 1996 and 1997 (see Table 3), and yet, calving time was significantly later in 1997 than in 1996 and 1998. The snow conditions and pasture availability in late winter - early spring, and especially in May, were markedly worse in 1997 than in 1996 and 1998 (see Table 2). This period coincides with the major growth of the foetus in reindeer (e.g. Krog, Wika & Savalov 1979, Roine, Nieminen & Timisjarvi 1982). During the last week of March, the Snøhetta area received large amounts of snow and local farmers could not remember similar snow depths in late April–May (P Fale, pers. comm.). The reindeer in Snøhetta grazed in smaller groups during calving in 1997 than in 1996, probably because pasture could only be reached on a few patchy wind-exposed ridges. Lengthened gestation rather than delayed breeding may have caused the late calving in Snøhetta in 1997. However, the lack of any significant correlation between snow depth and calving time for the whole data set suggests that other variables affecting pasture availability, like snow hardness and wind exposure in rugged terrain, may be more important.

McEwan & Whitehead (1972) measured the gestation length of reindeer (208.0 + 2.9 days) and caribou (216.4 ± 1.7 days) fed ad libitum. These gestation periods are considerably shorter than the average of 225–227 days reported by Skjenneberg & Slagsvold (1968). Bergerud (1975) concluded that breeding dates of Newfoundland caribou Rangifer tarandus caribou vary little between years, and that the variable calving dates may result from differences in gestation length related to pasture availability. Espmark (1980) conducted a nutrition experiment with two groups of reindeer from the same population, and found a non-significantly longer gestation period of four days in the poorly fed group. More female than male foetuses in the food restricted group (7:2 vs 2:7 in the unrestricted group) may have contributed to the calving time differences. However, Varo (1972) found that male calves are bom later or at the same time as female calves. Skogland (1983) reported later calving by wild reindeer in Snøhetta following winters of deep, persistent snow, but supplied no data. In a more recent study, Cameron, Fancy, Gerhart & White (1992) suggested that maternal undernourishment late in the gestation period might delay parturition. However, Thomson (1977) found the same gestation length of 225–228 days in wild reindeer in North Ottadalen and Hardangervidda even though winter pastures and physical condition in Hardangervidda were markedly worse than in North Ottadalen (Gaare 1968).

The results from studies on other ungulates suggest that gestation can be lengthened by reduced nutrition and physical condition. In a study on penned white-tailed deer, Verme (1965) found a 4–6 day shorter gestation length in high- than in low-diet groups. In a study of bison Bison bison, late-breeding cows in good condition produced calves at the normal time, whereas late-breeding cows in poor condition had significantly longer gestation than cows in good condition (Berger 1992). In an experimental study on sheep, Holst & Allan (1992) found that a period of nutritional restriction in the last part of the gestation period lengthened this. In horses Equus caballus, well-fed mares had shorter gestation than mares on a maintenance ration (Howell & Rollins 1951). Exceptions are Cox (1964), who found that the gestation length in pigs Sus scrofa was unrelated to the live weight and backfat thickness of the sows, and Alexander (1956), who found that undernutrition during late pregnancy shortened the duration of gestation in sheep.

If the adaptive time of calving varies with climate, and if populations have evolved in different climatic regions, a difference in calving time among populations could be developing genetically through natural selection (Skogland 1989).

Røed (1985, 1986) showed that wild and semi-domestic reindeer in southern Norway are genetically different. The geographic origin of domesticated reindeer is unclear because different herds have been mixed and moved by man several times through history. The Ottadalen populations are mainly of domestic origin (Reimers & Sørumgård 1995), probably from the forested areas in Trøndelag and Sweden (Mølmen 1991). According to Skogland (1989), the reindeer at Snøhetta are descendants of the original wild reindeer of south-ern Norway that are adapted to high mountain areas. However, immigration of escaped domestic reindeer and reindeer from North Ottadalen has occurred (Ø. Mølmen, pers. comm.). Our study shows that the Snøhetta population is calving later than the North Ottadalen population at the same level of physical condition. The difference may be genetically determined, caused by different adaptive calving times in different geographical areas in the past. More data are needed to test this hypothesis.



Aarthun Ims, A. 1996: Tidlig kalvedødelighet i tre sør-norske villreinområder med ulik beitestatus. - M.Sc. thesis, Agricultural University of Norway, 61 pp. (In Norwegian). Google Scholar


Alexander, G. 1956: Influence of nutrition upon duration of gestation in sheep. - Nature 178: 1058–1059. Google Scholar


Berger, J. 1992: Facilitation of reproductive synchrony by gestation adjustment in gregarious mammals: A new hypothesis. - Ecology 73: 323–329. Google Scholar


Bergerud, A.T. 1975: The reproductive season of Newfoundland caribou. - Canadian Journal of Zoology 53: 1213–1221. Google Scholar


Cameron, R.D., Fancy, S.G., Gerhart, K.L. & White, R.G. 1992: Calving success of female caribou in relation to body weight. - Canadian Journal of Zoology 71: 480–486. Google Scholar


Caughley, G. & Caughley, J. 1974: Estimating median date of birth. - Journal of Wildlife Management 38: 552–556. Google Scholar


Cox, D.F. 1964: Relation of litter size and other factors to the duration of gestation in the pig. - Journal of Reproduction and Fertility 7: 405–407. Google Scholar


Dauphiné, T.C. & McClure, R.L. 1974: Synchronous mating in Canadian barren-ground caribou. - Journal of Wildlife Management 38: 54–66. Google Scholar


Eloranta, E. & Nieminen, M. 1986: Calving of the experimental reindeer herd in Kaamanen during 1970 - 85. - Rangifer, Special Issue No.1. pp. 115–221. Google Scholar


Espmark, Y. 1971: Antler shedding in relation to parturition in female reindeer. - Journal of Wildlife Management 35: 175–177. Google Scholar


Espmark, Y. 1980: Effects of maternal pre-partum under nutrition on early mother - calf relationships in reindeer. - In: Reimers, E., Gaare, E. & Skjenneberg S. (Eds.); Proceedings of the Second International Reindeer/Caribou Symposium, Røros, Norway, pp. 485–496. Google Scholar


Finney, D.J. 1971: Probit analysis. - Cambridge University Press, Cambridge, 333 pp. Google Scholar


Gaare, E. 1968: A preliminary report on winter nutrition of wild reindeer in the southern Scandes, Norway. - Symposium of the Zoological Society of London 21: 109–115. Google Scholar


Gunn, R.G. & Doney J.M. 1975: The interaction of nutrition and physical condition at mating on ovulation rate and early embryo mortality in Scottish Blackface ewes. - Journal of Agricultural Science (Cambridge) 85: 465–470. Google Scholar


Haagenrud, H. & Markgren, G. 1974: The timing of estrus in moose (Alces alces L.) in a district of Norway. - Transactions of the Eleventh International Congress of Game Biology, Stockholm, pp. 71–78. Google Scholar


Hageland, J. 1987: Villreinstammen i Snøhettaområdet 1970–1986. - Villreinen 1: 57–60. (In Norwegian). Google Scholar


Hamilton, W.J. & Blaxter, K.L. 1980: Reproduction in farmed red deer. 1. Hind and stag fertility. - Journal of Agricultural Science (Cambridge) 95: 261–273. Google Scholar


Hansen, I. 1987: Snøhettastammen - villreinforvaltning frem til 1970. - Villreinen 1: 39–40. (In Norwegian). Google Scholar


Heitkøtter, O. 1981: Villrein og villreinjakt. - Grøndahl & Søn Forlag A.S, Oslo, 151 pp. (In Norwegian). Google Scholar


Holst, P.J. & Allan, C.J. 1992: The timing of moderate nutritional restriction in mid pregnancy and its effect on lamb birth weight and ewe gestation length. - Australian Journal of Experimental Agriculture and Animal Husbandry (Melbourne) 32: 11–14. Google Scholar


Holthe, V. 1975: Calving season in different populations of wild reindeer in South Norway. - In: Proceedings of the First International Reindeer/Caribou Symposium, Fairbanks, Alaska. Biological Paper, University of Alaska, Special Report 1: 194–198. Google Scholar


Howell, C.E. & Rollins, W.C. 1951: Environmental sources of variation in the gestation length of the horse. - Journal of Animal Science 10: 789–796. Google Scholar


Jordhøy, P. 1994: Naturarv i faresonen, men god utvikling hos Snøhettareinen. - Villreinen 8: 34–37. (In Norwegian). Google Scholar


Jordhøy, P., Strand, O., Skogland, T., Gaare, E. & Holmstrøm, F. 1996: Oppsummeringsrapport, overvåkningsprogram for hjortevilt - villreindelen 1991–95. - NINA fagrapport 22: 1–57. (In Norwegian). Google Scholar


Krog, J., Wika, M. & Savalov, P. 1979: The development of the foetus of the Norwegian reindeer. - In: Reimers, E., Gaare, E. & Skjenneberg, S. (Eds.); Proceedings of the Second International Reindeer/Caribou Symposium, Røros, Norway, pp. 306–310. Google Scholar


Langvatn, R. (Ed.) 1977: Criteria of physical condition, growth and development in Cervidae, - suitable to routine studies. - Nordic Council for Wildlife Research, Stockholm, 27 pp. Google Scholar


Lenvik, D. 1988: Selection strategy in domestic reindeer. 6. Oestrus peak and oestrus synchronization in domestic reindeer in Trøndelag County, Norway. - Norsk landbruksforskning 2: 163–174. Google Scholar


McEwan, E.H. & Whitehead, P.E. 1972: Reproduction in female reindeer and Caribou. - Canadian Journal of Zoology 50: 43–46. Google Scholar


Mitchell, B. & Lincoln, G.A. 1973: Conception dates in relation to age and condition in two populations of red deer in Scotland. - Journal of Zoology (London) 171: 141–152. Google Scholar


Mølmen, Ø. 1991: Ottadalsreinen. Fra pil og bue til lasso og gevaer. - Engers Boktrykkeri A/S, Otta, Norway, 290 pp. (In Norwegian). Google Scholar


Reimers, E. 1968: Vekstforskjeller hos rein (Rangifer tarandus L.) i to sørnorske fjellområder. - M.Sc. thesis, University of Oslo, 61 pp. (In Norwegian). Google Scholar


Reimers, E. 1972: Growth in domestic and wild reindeer in Norway. - Journal of Wildlife Management 36: 612–619. Google Scholar


Reimers, E. 1983a: Growth rate and body size differences in Rangifer. A study of causes and effects. - Rangifer 3: 3–15. Google Scholar


Reimers, E. 1983b: Reproduction of wild reindeer in Norway. - Canadian Journal of Zoology 61: 211–217. Google Scholar


Reimers, E. 1997: Rangifer population ecology: a Scandinavian perspective. - Rangifer 17(3): 105–118. Google Scholar


Reimers, E. & Sørumgård, R. 1995: Nord-Ottadalsreinen 30 ˚retter starten. - Villreinen 9: 22–26. (In Norwegian). Google Scholar


Roine, K., Nieminen, M. & Timisjarvi, J. 1982: Foetal growth in the reindeer. - Acta Veterinaria Scandinavica 23: 107–117. Google Scholar


Røed, K.H. 1985: Genetic differences at the transferrin locus in Norwegian semidomestic and wild reindeer (Rangifer tarandus L.). - Hereditas 102: 199–206. Google Scholar


Røed, K.H. 1986: Genetic variability in Norwegian wild reindeer (Rangifer tarandus L.). Hereditas 104: 293–298. Google Scholar


Skjenneberg, S. & Slagsvold, L. 1968: Reindriften og dens naturgrunnlag. - Universitetsforlaget, Oslo, 332 pp. (In Norwegian). Google Scholar


Skogland, T. 1983: The effects of density dependent resource limitation on size of wildreindeer. - Oecologia 60: 156-168. Google Scholar


Skogland, T. 1984: The effects of food and maternal conditions on fetal growth and size in wild reindeer. - Rangifer 4: 39–46. Google Scholar


Skogland, T. 1989: Comparative social organization of wild reindeer in relation to food, mates and predator avoidance. - Advances in Ethology 29, Supplements to Ethology, 74 pp. Google Scholar


Strand, O., Jordhøy, R. & Holmstrøm, F. 1996: Rapport fra kjeveinnsamlingen 1995. - Villreinen 10: 98–105. (In Norwegian). Google Scholar


Thomson, B. 1977: The behavior of wild reindeer in Norway. - PhD thesis, University of Edinburgh, 428 pp. Google Scholar


Varo, M. 1972: Investigations on the possibilities of reindeer breeding II. - Journal of the Scientific Agricultural Society (Finland): 234–248. Google Scholar


Verme, L.J. 1965: Reproduction studies on penned whitetailed deer. - Journal of Wildlife Management 29: 74–79. Google Scholar


Verme, L.J. 1969: Reproductive pattern of white-tailed deer related to nutritional plane. - Journal of Wildlife Management 33: 881–887. Google Scholar


Verme, L.J., Ozoga, J.J. & Nellist, J.T. 1986: Induced early estrus in penned white-tailed deer does. - Journal of Wildlife Management 51: 54–46. Google Scholar
Kjetil Flydal and Eigil Reimers "Relationship between calving time and physical condition in three wild reindeer Rangifer tarandus populations in southern Norway," Wildlife Biology 8(1), 145-151, (1 June 2002).
Received: 8 December 1999; Accepted: 12 July 2001; Published: 1 June 2002

Back to Top