Variation in gestation length among captive reindeer (Rangifer tarandus tarandus)

An estimated 90% of reindeer females are mated in a 10- to 21-d interval and give birth in an equally synchronized manner. Reported gestation length in reindeer is highly variable (range, 203 to 240 d), almost twice the reindeer estrous cycle length. Previously, we identified a significant, negative relationship between gestation length and conception date in a small group of reindeer. In the current study, the negative relationship was investigated in a switchback design, where reindeer were divided into two groups synchronized for early and late mating over a 2-yr trial. Regression analysis of 11 paired observations produced a negative (P < 0.001) association between gestation length and conception date (slope = − 0.31). Dam weight at breeding and prior to parturition, calf birth weight, and calf sex were not significant variables in the regression. Regression analysis of a larger data set from two University of Alaska Fairbanks reindeer herds, where conception date (verified by systemic progesterone) and gestation length were recorded (historical data set), supported previous conclusions (n = 70; slope = −0.37; P < 0.001). Although the calf sex ratio did not differ with gestation length, there was a positive relationship (r² = 0.19; P = 0.014) between male birth weight and gestation length in the larger data set. The negative relationship between conception date and gestation length enhanced calving synchrony, though the limits of gestation plasticity and underlying mechanisms are not clear. The potential role of photoperiod on early embryonic development is discussed.     

Population genetics of the native caribou (Rangifer tarandus groenlandicus) and the semi-domestic reindeer (Rangifer tarandus tarandus) in Southwestern Greenland: Evidence of introgression

Over the past centuries the native caribou ofWest Greenland has gone through extensive population size fluctuations, with reductionsas great as 90% in less than 20 years.Norwegian semi-domestic reindeer wereintroduced to the Nuuk area in 1952 because ofthe small number of caribou in Greenland.Although the reindeer and caribou wereinitially kept separated, mixing has occurredsince the 1970's. We investigated the genotypicstructure of caribou and reindeer in South-westGreenland, using five polymorphicmicrosatellite markers isolated from cattle,sheep, goat and red deer. A total of ninetysamples were collected, which included samplesfrom caribou of four different regions andsamples from two different reindeer herds.Based on the genetic variation of the fivemarkers, our results shows that the caribou andthe reindeer populations in the six regionssampled are genetically differentiated withineach group and the two subspecies aredifferentiated from each other. A likelyexplanation for the genetic isolation of thepopulations investigated is that naturalbarriers (glaciers and wide fjords) exists inthe area. Furthermore we found that introducedNorwegian domestic reindeer hybridized with thenative Greenlandic caribou in two areasneighbouring Nuuk.     

No evidence of inbreeding avoidance in a polygynous ungulate: the reindeer (Rangifer tarandus)

In polygynous species, mate choice is an integrated part of sexual selection. However, whether mate choice occurs independently of the genetic relatedness among mating pairs has received little attention, although inbreeding may have fitness consequences. We studied whether genetic relatedness influenced females' choice of partner in a highly polygynous ungulate--the reindeer (Rangifer tarandus)--in an experimental herd during two consecutive rutting seasons; the herd consisting of 75 females in 1999 and 74 females in 2000 was exposed to three 4.5-year-old adults and three 1.5-year-old young males, respectively. The females' distribution during peak rut was not influenced by their genetic relatedness with the dominant males of the mating groups. Further, genetic relatedness did not influence the actual choice of mating partner. We conclude that inbreeding avoidance through mating group choice as well as choice of mating partner, two interconnected processes of female mate choice operating at two different scales in space and time, in such a highly female-biased reindeer populations with low level of inbreeding may not occur.     

Genetic variation in caribou and reindeer (Rangifer tarandus)

Genetic variation at seven microsatellite DNA loci was quantified in 19 herds of wild caribou and domestic reindeer (Rangifer tarandus) from North America, Scandinavia and Russia. There is an average of 2.0-6.6 alleles per locus and observed individual heterozygosity of 0.33-0.50 in most herds. A herd on Svalbard Island, Scandinavia, is an exception, with relatively few alleles and low heterozygosity. The Central Arctic, Western Arctic and Porcupine River caribou herds in Alaska have similar allele frequencies and comprise one breeding population. Domestic reindeer in Alaska originated from transplants from Siberia, Russia, more than 100 years ago. Reindeer in Alaska and Siberia have different allele frequencies at several loci, but a relatively low level of genetic differentiation. Wild caribou and domestic reindeer in Alaska have significantly different allele frequencies at the seven loci, indicating that gene flow between reindeer and caribou in Alaska has been limited.     

Milk composition and lactational output in the greater spear-nosed bat, Phyllostomus hastatus

Growth rates of mammalian young are closely linked to the ability of the mother to provide nutrients; thus, milk composition and yield provide a direct measure of maternal investment during lactation in many mammals. We studied changes in milk composition and output throughout lactation in a free-ranging population of the omnivorous bat, Phyllostomus hastatus. Fat and dry matter of milk increased from 9 to 21% and from 21 to 35% of wet mass, respectively, throughout lactation. Energy increased from 6 to 9 kJ · g⁻¹ wet mass, primarily due to the increase in fat concentration. Total sugar levels decreased slightly but non-significantly. Mean sugar level was 4.0% of wet mass. Protein concentration increased from 6 to 11% of wet mass at peak lactation and then decreased as pups approached weaning age. Total milk energy output until pups began to forage was 3609 kJ. Milk levels of Mg, Fe, Ca, K, and Na averaged 0.55 ± 0.26, 0.23 ± 0.2, 8.75 ± 4.17, 5.42 ± 2.11, and 9.87 ± 4.3 mg · g⁻¹ dry matter, respectively. Of the minerals studied, calcium appears to be most limiting in this species. The high degree of variability in foraging time, milk composition and milk yield between individuals at the same stage of lactation could potentially yield high variance in reproductive success among females of this polygynous species. Accepted: 23 January 1997     

Effects of natural winter pasture and commercial pellet on the ultrastructure of small intestinal epithelium in reindeer

Segments of small intestine (duodenum, jejunum and ileum) from slaughtered reindeer (Rangifer tarandus tarandus) grazing natural winter pastures (n=3) and reindeer fed commercially available pellets (RF-80) in winter (n=5) were collected and immediately fixed in McDowells fixative. Transmission electron microscopy was employed to investigate the ultrastructural features of the epithelium and lamina propria along the small intestine and to relate these to the different diets. Major differences in ultrastructural features were observed between the small intestinal enterocytes of reindeer fed the two diets. Enterocytes in reindeer fed the natural diet displayed a normal appearance with a dense cytoplasm and distinct microvilli. In contrast, reindeer fed the commercial diet showed damaged enterocytes amongst the normal cells. Abnormal changes included disintegration and loss of microvilli, cytoplasmic swelling, loss of membrane integrity and increases in the width of intercellular spaces, especially in the jejunum. The transport and holding of animals was supported by a grant from the Reindeer Husbandry Research Fund.     

Remains of Late Pleistocene reindeer from Chmielewo,northeast Poland

Reindeer (Rangifer tarandus L.) remains in Europe are well represented in Late Pleistocene sites in France, Germany, Ukraine, Poland and other countries. In a chalk mine at Chmielewo (near niardwy Lake, NE Poland) four antlers were recovered. Radiocarbon assays date the fossils to the end of the Pleistocene. All antlers belong to male reindeer. One of the discovered specimens is an uncast antler of the tundra reindeer form, while the others are of the woodland reindeer form. The uncast antler has distinctly visible parieto-frontal fixation of the beam to the skull that confirms its parallel position in relation to the ground.     

Redescription of Besnoitia tarandi (Protozoa: Apicomplexa) from the reindeer (Rangifer tarandus)

Besnoitia tarandi tissue cysts were found in naturally-infected reindeer (Rangifer tarandus) from Finland. Infectivity of its tissue cysts, bradyzoites, and tachyzoites to animals and cell culture was studied. The bradyzoites and tissue cysts were not infectious to out-bred mice, rabbits or gerbils. When fed tissue cysts, neither cats nor dogs excreted oocysts. However, the parasite was lethal to interferon-gamma gene knock out mice irrespective of the route of inoculation. The parasite was grown successfully in African Green Monkey cells from tissues of two reindeer for the first time. Non-dividing, uninucleate tachyzoites from smears from cell cultures were 5.6 x 1.4 microm (4.5-7.4 x 1.0-1.9, n=50) in size. Longitudinally-cut bradyzoites in tissue sections measured 7.4 x 1.3 microm (6.5-7.8 x 1.0-1.6, n=30). Ultrastructurally, tachyzoites and bradyzoites were similar to those in other Besnoitia species, and in particular to parasites described from cattle (Besnoitia besnoiti) and equids (Besnoitia bennetti) in that their bradyzoites lacked enigmatic bodies. Based on comparative analysis of three portions of nuclear ribosomal DNA (the small and large subunits and the first internal transcribed spacer) B. tarandi was found to be more closely related to the other congeners described from ungulates. The parasite was formally redescribed and specimens deposited in the US National Parasite Collection.     

Merging and comparing three mitochondrial markers for phylogenetic studies of Eurasian reindeer (Rangifer tarandus)

Phylogenetic analyses provide information that can be useful in the conservation of genetic variation by identifying intraspecific genetic structure. Reconstruction of phylogenetic relationships requires the use of markers with the appropriate amount of variation relative to the timeframe and purpose of the study. Here, genetic structure and clustering are inferred from comparative analyses of three widely used mitochondrial markers, the CR, cytb and the COI region, merged and separately, using Eurasian reindeer as a model. A Bayesian phylogeny and a MJ network, both based on the merged dataset, indicate several distinct maternal haplotype clusters within Eurasian reindeer. In addition to confirm previously described clusters, two new subclusters were found. When comparing the results from the merged dataset with the results from analyses of the three markers separately, similar clustering was found in the CR and COI phylogenies, whereas the cytb region showed poor resolution. Phylogenetic analyses of the merged dataset and the CR revealed congruent results, implying that single sequencing analysis of the CR is an applicable method for studying the haplotype structure in Eurasian reindeer.     

Personality and fitness consequences of flight initiation distance and mating behavior in subdominant male reindeer (Rangifer tarandus)

Animal personality has been studied extensively in recent years, yet multidimensionality in tendencies of risk‐related behavior, and the role of such consistency from a mating tactics perspective, is yet to be investigated. We used a semi‐domesticated herd of reindeer (Rangifer tarandus) to examine individual subdominant male propensity to risk mating attempts on guarded females, as well as flight initiation distance (FID), within the personality paradigm to elucidate potential fitness consequences of consistency from an adaptive perspective. Data were collected at the Kutuharju Reindeer Research Station in Kaamanen, Finland, where measures of personality were generated using field observation data based on the relative frequency of dominant male–subdominant male agonistic interactions over 4 years and subdominant males' FID measured over 1 year. Individual propensity for transient mating attempts was not significantly repeatable and did not significantly predict reproductive success or somatic cost during the mating season. Individuals varied consistently in FID, and although repeatable, FID was not related to reproductive success or somatic cost. Proximate state‐dependent or social mechanisms may be driving decision‐making with respect to mating effort, whereas consistent between‐individual differences in FID may be maintained by mechanisms unrelated to life‐history trade‐offs involving productivity.     

Neandertal mobility and large-game hunting: The exploitation of reindeer during the Quina Mousterian at Chez-Pinaud Jonzac (Charente-Maritime, France)

Neandertals were effective hunters of large ungulates throughout their geographic and temporal ranges. Equipped with this knowledge, researchers in paleoanthropology continue to seek insight on the relationships between hunting and subsistence strategies with other components of the Neandertals’ niche, such as mobility, site use, and lithic technology. The Quina Mousterian deposits from the rockshelter site of Chez Pinaud Jonzac (Charente-Maritime, France; hereafter Jonzac) offer an excellent opportunity to pursue these issues. This paper focuses on the extensive and well-preserved skeletal remains of reindeer (Rangifer tarandus) recovered from recent excavations of the site, representing at least 18 individuals that were hunted by Neandertals during the fall through winter. Our zooarchaeological results indicate that all ages of reindeer were hunted but adult individuals predominate. No bias is evident in the comparable frequencies of males and females. These prey were butchered on-site, with abundant evidence of meat filleting and marrow exploitation. In the excavated sample, the absence of hearths and the almost complete lack of burned bones or stones suggest that Neandertals were not using fire to assist with processing the reindeer carcasses. The zooarchaeological results presented here indicate that reindeer were hunted during a restricted window of time when they were seasonally abundant in the local area near Jonzac. Taken together with the lithic industry based on bifacial elements, the evidence is consistent with a pattern of site use by highly mobile hunter-gatherers making frequent, short-term visits. Ongoing research at Jonzac and other Quina Mousterian localities will contribute to a better understanding of Neandertal behavior during cold climate phases.     

Lactation in the Japanese monkey (Macaca fuscata): Yield and composition of milk and nipple preference of young

Changes in the yield and chemical composition of milk, together with those in the nipple preferences and suckling behavior of infants, were followed in three lactating Japanese monkeys rearing single infants under laboratory conditions at monthly intervals for six months after their paturition. Milk accumulating in the mammary glands during a 4-hr separation of the infant was collected by milking under anesthesia with the aid of a physiological dose of oxytocin. The stage of full lactation appeared to last for about two or three months after parturition. The milk at this stage contained 14.0% of total solids, 4.2% of lipids, 1.6% of proteins, and 6.2% of lactose, and the concentrations of Na, Cl, and K in the milk water were 7.4, 15.1, and 5.9 mM, respectively. From the 9th or 13th week of lactation onwards, according to the individual, the milk composition changed appreciably and the time during which the young left hold of the mother's nipple also increased. The weaning of young in the Japanese monkey appears to begin during the 3rd or 4th month of age. The milk production then wanes and almost ceases by the end of the 6th month. The nipple preference of the young was generally established completely by the 3rd, or the 8th at latest, week of age. However, no difference in either the yield or composition of the milk secreted was found between the mammary glands of the preferred and non-preferred sides. Without regard to the apparent nipple preference, infants seem to ingest milk from the mother's breasts of both sides. Accurate estimation of the rate of milk production could not be achieved, but the rate was expected to be 150–200 g/day at the height of lactation based on the relation between the mother's body weight and the milk production rates of other primate species. A disparity was noted between the observed and estimated values for the milk yield, and a diurnal fluctuation in the milk secretion of the Japanese monkey was inferred. This study was conducted through the official system of the Primate Research Institute, Kyoto University, for cooperative research work with other institutions.     

Heterogeneity in individual quality overrides costs of reproduction in female reindeer

Reproductive allocation at one age is predicted to reduce the probability of surviving to the next year or to lead to a decrease in future reproduction. This prediction assumes that reproduction involves fitness costs. However, few empirical studies have assessed whether such costs may vary with the age at primiparity or might be overridden by heterogeneities in individual quality. We used data from 35 years’ monitoring of individually marked semi-domestic reindeer females to investigate fitness costs of reproduction. Using multi-state statistical models, we compared age-specific survival and reproduction among four reproductive states (never reproduced, experienced non-breeders, reproduced but did not wean offspring, and reproduced and weaned offspring) and among contrasted age at primiparity. We assessed whether reproductive costs occurred, resulting in a trade-off between current reproduction and future reproduction or survival, and whether early maturation was costly or rather reflected differences in individual quality of survival and reproduction capabilities. We did not find any evidence for fitness costs of reproduction in female reindeer. We found no cost of gestation and lactation in terms of future reproduction and survival. Conversely, successful breeders had higher survival and subsequent reproductive success than experienced non-breeders and unsuccessful breeders, independently of the age at primiparity. Moreover, it was beneficial to mature earlier, especially for females that successfully weaned their first offspring. Successful females at early primiparity remained successful throughout their life, clearly supporting the existence of marked among-female differences in quality. The weaning success peaked for multiparous females and was lower for first-time breeders, indicating a positive effect of experience on reproductive performance. Our findings emphasize an overwhelming importance of individual quality and experience to account for observed variation in survival and reproductive patterns of female reindeer that override trade-offs between current reproduction and future performance, at least in the absence of harsh winters.     

The effect of cloprostenol in non-pregnant and pregnant Norwegian semi-domestic reindeer (Rangifer tarandus tarandus L)

Two non-pregnant and five pregnant 1.5-year-old semi-domestic reindeer were used to study the effect of cloprostenol given during the luteal phase of the oestrous cycle, or at two stages of pregnancy (early December, n = 3, and mid-January, n = 2). Blood samples were collected at 3-hourly intervals from immediately prior to treatment until 6–8 days after treatment, after which blood samples were collected every second day. Prior to each blood collection, the animals were observed for signs of oestrus. Plasma progesterone, oestradiol-17β, luteinizing hormone (LH) and 15-ketodihydro-PGF_2α were analyzed to characterize variations in ovarian function.Treatment with cloprostenol resulted in an immediate and rapid decrease in plasma progesterone concentrations in all treated animals. The fall in plasma progesterone was associated with increase in 15-ketodihydro-PGF_2α. Oestrus, indicated by standing behaviour, was observed on three out of four occasions in the two non-pregnant animals. The average duration of standing behaviour (oestrus) was 27 h (range: 24–30 h).Of the pregnant females that were treated with cloprostenol in the beginning of December (n = 3), two aborted between 72 and 96 h after treatment. One of these developed pyometra after abortion. In one female the foetus died 2 days after treatment, but was retained within the uterus until slaughter 2.5 months later. One of the two females that were treated in mid-January aborted between 62–65 h after injection. The other female retained a live foetus until slaughter in February. There were few endocrinological differences between animals that aborted and those that did not, though aborting animals had lower progesterone concentrations for a longer period of time after treatment.It was concluded that cloprostenol can be used during the luteal phase of the oestrous cycle to induce luteolysis and oestrus. When given during pregnancy, cloprostenol can induce abortion, though undesired side effects make it inappropriate for practical use.     

Use of climatic data to assess the effect of insect harassment on the autumn weight of reindeer (Rangifer tarandus) calves

Considerable behavioural evidence supports harassment by insects as the most important causal link between warm summer temperatures and low body condition of reindeer Rangifer tarandus , and that insect activity is influenced by weather condition. However, much less is known about the effect of insect harassment on individual performance, measured as reduced weight gain during summer, and the related consequences on both the reindeer pastoral economy and reindeer as a biological resource. Using climatic data, this paper develops a simple index for the analysis of insect harassment that takes into consideration weather variables known to significantly affect insect activity and/or the level of insect harassment. The insect harassment index, which is based on mid-day ambient temperature ≥13 °C, wind speed <6 m/s and cloud cover <40%, is further used to test the hypothesis that insect harassment has a negative effect on reindeer performance during summer in three Norwegian populations. Results show that harassment by insects negatively affects the autumn weight of reindeer calves, most probably through reduced grazing time and increased energy expenditure, but also indirectly by negatively influencing milk production of the dam. Moreover, female calves were more vulnerable to insect harassment than males. Insect harassment may have consequences on future reproductive performance, calving time, calf birth weight and hence neonatal mortality, and thus affect reindeer productivity. The presented index is easy to estimate and may be used to quantify and compare harassment levels on various reindeer summer grazing areas for management purposes. Our results also suggest that the expected temperature increase in the course of global warming may increase the insect-related stress on reindeer.     

Sexual dimorphism and intercorhort variation in reindeer calf antler length is associated with density and weather

We analysed intercohort variability of live weight and antler length of 5,123 reindeer calves. We further assessed the influence of climate and density on the interannual variation in antler length, and discussed sex-specific resource allocation and response to climate variability. Antler length varied significantly among years and between sexes, with interaction between year and sex. Body weight and antler length were highly positively correlated, showed similar intercohort variability, and had a strong allometrical link, suggesting that antler length could be an equally reliable measure of calf condition as live weight. We found a relative measure of antler length (i.e. antler length corrected for the allometric effect of body mass) to be positively influenced by increasing density and May–June precipitation, and also decreasing May–June temperature. We attributed the effect of early summer weather to its influence on forage availability and quality as well as the level of parasitic insect harassment. Gender difference in both the allometric exponents and the interannual variability suggest that young males and females may have different tactics for relative resource allocation towards growth of antlers as compared to body mass. Because antlers are costly to produce, they may be an honest signal of individual quality for both sexes. However, we found gender-specific allometry, as female calves more than males appear to prioritize their antler growth over body mass, especially when resources are limited. Thus, our results suggest that environmental variation may influence the extent of sexual dimorphism in antler length. Electronic Supplementary Material Supplementary material is available for this article at