Further evidence for sex differences in suckling behaviour of captive plains zebra foals

Sex differences in suckling behaviour could be explained either by different maternal investment or by different behaviour of young. Previously, we found sex differences in rejection and termination of suckling bouts in captive plains zebras (Equus burchellii). In this study, we analysed the length of suckling bout interruptions and unsuccessful subsequent attempts which followed a successful suckling bout in plains zebra foals at Dvůr Králové Zoo. When a suckling bout was interrupted, male foals resumed the bout sooner than female foals. The probability of a subsequent attempt decreased with increasing age in female foals but did not change in male foals. These results demonstrate higher effort in suckling interest by male foals, who tried to suckle more than female foals. Although we found sex bias in the effort to suckle, which suggested higher parent–offspring conflict in male offspring, we cannot omit a sex bias in milk supply by the mother.     

The effects of twinning on mother—Offspring behavior in range beef cattle

Methods to increase the productivity of beef cattle include induced twinning and multiple fostering of calves on nurse cows, but little is known about the capacity of cows to rear more than one calf in a rangeland environment.Eight single and 14 twin calves and their mothers were studied in a 30.4-ha enclosure in a California rangeland environment from 2 to 20 weeks following parturition. Data were obtained on ingestive, grooming, agonistic, play and sexual behaviors, as well as spatial proximity of calves to mothers and peers.Initially, twins spent more time suckling their mothers than did single calves (presumably due to insufficient milk intake), but later adapted by utilizing natural forage and obtaining milk from alien cows. By 15–20 weeks of age, twins were suckling their dams for less than one-quarter of the time spent at 3–6 weeks, whereas the suckling time of single calves did not decline. Thus, twins may experience a natural early weaning from mother's milk.The hypothesis that mother—Offspring bonds are weaker with twins than with singles was supported by the fact that mothers bearing twins groomed their offspring less than mothers with singles, and twins were normally found at greater distances from their mothers than singles.Most long-distance cow—Calf separations resulted from the cow moving to feed or to obtain water. Reunion of mother and young depended on auditory communication; the calf normally traversed most of the intervening distance.     

Mother-calf relationships and maternal investment in European bison<Emphasis Type="Italic">Bison bonasus</Emphasis>

Mother-young relationships, up to the third month of the calves’ life, were investigated in European bisonBison bonasus (Linnaeus, 1758) from Białowieża National Park breeding centres (Poland). During the first week, calves spent most of their time close to their mothers and were rarely seen in the vicinity of other group members. Highest suckling rate, most frequent vocal contact and agonistic behaviour of mothers towards intruders, were other characteristics of this period. Although being a forest species, European bison exhibit a following type of strategy for offspring protection, typical for ungulates living in open areas; no hiding phase was observed. Suckling rates were similar in calves of both sexes, however, the pattern of nursing was different: male calves suckled longer, but in rarer bouts than female calves. The mothers’ condition, reflected by their social rank, did not influence the suckling rate. No sex differences were recorded in other maternal activities or mother-calf distance. The presumption of a lack of sex-biased maternal investment in European bison is confirmed by the results of other research.     

Preliminary study of mother–offspring conflict in black and gold howler monkeys (<Emphasis Type="Italic">Alouatta caraya</Emphasis>)

Parent–offspring conflict has been scarcely studied in Neotropical primates. In this study, we explored mother–offspring conflict in a group of wild black and gold howler monkeys (Alouatta caraya) in northeastern Argentina. We used the all-occurrences technique to record behaviors, completing 712 h of observation. The results showed that all immature individuals between 2 and 23 months expressed conflict with regard to suckling or traveling with their mothers. Successful suckling attempts negatively correlated with the age of the immatures, occurring least frequently with the presence of newborns. In the juvenile period, the decline in successful attempts was a consequence of juveniles reducing suckling attempts and mother rejection.     

SUCKLING BEHAVIOR IN SPERM WHALE CALVES: OBSERVATIONS AND HYPOTHESES

This study is the first to describe quantitatively the apparent suckling behavior of sperm whale, Physeter macrocephalus (Linnaeus, 1758), calves using observations from both above and below the surface. Peduncle dives are short (mean 14 s) dives made by sperm whale calves beside the peduncle of an adult female, which were previously assumed to be indicative of suckling. Photo-identification and focal calf-follows were used to collect data during 177 peduncle dive bouts from 22 different calves (11 calves from the Caribbean Sea, 11 from the Sargasso Sea), one of which was followed on forty different days. We found that peduncle diving in sperm whale calves is laterally asymmetrical with a bias to the left side of the escorting adult (69.8% of peduncle dives) and that calves generally do not switch sides during a bout of peduncle dives (switches occurred in only 10.8% of bouts). Further subsurface observations gave insight into potential alternative functions of peduncle diving. These alternative hypotheses, including nasal suckling, and the existing supporting evidence for each are discussed. It is likely that peduncle diving is related to suckling but that the exact function of the dives and manner in which sperm whale calves ingest milk remains unclear.     

Nursing behavior and early development of impala at San Diego Wild Animal Park

Because impala are commonly exhibited and handreared in zoos and their natural nursing behavior had not previously been studied, we examined nursing and early development in five impala calves housed in a large, naturalistic enclosure. Calves were observed for the first 5 weeks of life during 12-hr continuous watches and 20-min focal animal samples. Total daily suckling time decreased while time grazing and feeding on concentrates increased from 1–5 weeks of age. An increasing proportion of nursing bouts were terminated by the dam as calves matured, with dams terminating almost 70% of bouts during the first week. Suckling success and maternal grooming also decreased after week I, suggesting that impala mothers cut back early on nursing and grooming of offspring. Rapid decline in mother-young spatial proximity and a concomitant increase in calf association with age-mates over time suggests that the mother-young bond is weak and ephemeral in impala. An example of the implications of our results for improving handrearing programs would be that newborn calves should be started on a daylight feeding schedule of one bottle-feeding every three hours, and that they not be allowed to gorge themselves at any one of these feedings.     

Effect of age of calf on suckling behaviour and other behavioural activities of Zebu and crossbred calves during restricted suckling periods

The objective of this study was to investigate the effect of age of calf on the behaviour of Zebu and crossbred calves during restricted suckling (RS) periods. The behaviours of 20 Zebu and 16 crossbred calves were recorded during two 30-min sessions each day after milking when the calves and their dams were brought together in a group for suckling. This was made for a time period of 2 weeks/month for 6 months postpartum.The total suckling duration was significantly longer in Zebu calves (11.8+/-0.19 min) compared to the crossbred calves (9.4+/-0.19 min), but decreased significantly in both breeds with increasing age from 1 to 6 months. The number of suckling bouts decreased from a mean of 3.8 at 1 month of age to 1.1 at 6 month (P<0.05). The duration of each suckling bout decreased significantly from a mean of 3.5+/-0.15 min at 1 month of age to 1.6+/-0.01 min at 6 months (<0.05). The frequency of crossbred calves cross-suckling (3.7%) was significantly higher than that of the Zebu calves (1.9%; P<0.05). The frequency of calves cross-suckling decreased significantly from 4.2% at 1 month of age to 2.3% at 6 months. The duration and number of bouts of cross-suckling was significantly higher in the crossbred calves (duration 0.9+/-0.06 min; bouts 3, 7) than in the Zebu calves (duration 0.5+/-0.06 min; bouts 2, 7) and decreased with increasing age of calf. The duration and number of bouts of inter-sucking was significantly higher in the crossbred calves (duration 0.6+/-0.07 min; bouts 1, 6) than in the Zebu calves (duration 0.1+/-0.04 min; bouts 0, 5) and decreased with increasing age of calf. Exploration increased in duration as the calves increased in age from 1 to 6 months (P<0.05). The duration of play increased significantly with the increase in age of calf from 1 to 6 months, and occurred mainly after nursing.     

Mother–young distance in Japanese Black cattle at pasture

Distance between dam and offspring (1–121 days old) in a herd of Japanese Black cattle (Bos taurus) grazing a tropical grass (Paspalum notatum) pasture (1.5 ha) was investigated during 7-h grazing periods over grazing seasons from May (spring) to October (autumn). The mother–young distance was not constant throughout the grazing period, repeatedly increasing and decreasing. Although significant periodicity was always detected in the mother–young distance, there was no consistent dominant cycle, indicating the complexity of the within-day pattern of mother–young distance. The mean mother–young distance over the grazing period increased as a calf aged, reaching a plateau at an age of about 33 days. The mean distance of a calf from its mother was usually shorter than that from a non-mother cow, with the difference between the mean distances decreasing sharply until a calf became about 35 days old. The results and literature show that mutual independence of mother and young rapidly develops in the first 30–50 days after parturition. Electronic Publication     

Behaviour of Zebu and crossbed cows in restricted suckling groups

The aim of this study was to investigate whether Zebu (Bos indicus) and crossbred (Bos indicusxBos taurus) cows differ in maternal related behaviour during restricted group suckling. The behaviours of 20 Zebu and 16 crossbred cows were recorded during two 30min sessions each day after milking when their calves were present for suckling, for a time period of 2 weeks per month for 6 months postpartum. The main activity in both breeds during the 0.5h observation sessions was suckling. However, the two breeds differed significantly in several behavioural aspects. The Zebu cows had longer total duration of suckling than the crossbred cows, per 30min session, 11.8 and 9.4min, respectively. The separate suckling bouts were longer in the Zebu cows (2.8min in Zebu and 2.3min in crossbred) and this breed also had more suckling bouts than the crossbred per session, 3.8 and 3.2, respectively. Zebu cows stayed in close contact with their calves for longer time and directed more agonistic actions against alien calves and cows than the crossbred cows.     

A case of adoption and allonursing in captive plains zebra (Equus burchellii)

Although allonursing (allowing non-filial offspring to suckle) can be a costly behaviour, it has been reported for many mammals including ungulate species. However, such behaviour is very rare in equids. This is the first report on adoption and allonursing in captive plains zebra (Equus burchellii), recorded in the Dv?r Králové Zoo, Czech Republic. We observed a case of adoption of an orphaned foal by a lactating mare, who then regularly nursed two foals (filial and non-filial). The allonursing mare rejected more suckling attempts, terminated suckling bouts more often, and had a shorter suckling bout duration than other mares. When nursing both foals at the same time, the suckling bout lasted for less time than when nursing a single foal, regardless of whether it was filial or non-filial. The allonursing mare apparently did not discriminate between the filial and non-filial foal.     

Aggression and Nearest Neighbour Distances in Female Reindeer during the Rut

Data on nearest neighbours and aggressive behaviour were collected within rutting groups of semi-domesticated reindeer (Rangifer t. tarandus L.) in a 1300-ha pasture in Finnish Lapland, and wild forest reindeer (Rangifer t. fennicus Lönnb.) in a 15-ha enclosure in Central Finland. Adult cows of forest reindeer charged yearling males, yearling females and calves in that order of decreasing frequency. Semi-domesticated reindeer cows rushed yearling females more often than they did one another. One suggested influence of antagonism by cows were the observed intragroup associations of yearling females. Cows were tolerant toward their own yearling females, but not toward their own yearling males. Although no maternal aggression toward calves was found, male calves moved away more often from their mothers than did female calves during the post-rut period.     

The nest-holding grass goby (Zosterisessor ophiocephalus) male adjusts the spawning activity in relation to parasitic nest intrusions

This study examines the temporal pattern of spawning behavior by the territorial (i.e. nest-holding) grass goby male, Zosterisessor ophiocephalus, in response to sneak intrusions by the small parasitic male under controlled laboratory conditions. The spawning activity of the territorial male consists of a sequence of upside–down movements on the ceiling of the nest accompanied by undulations of the body and sperm release. Five pairs of one territorial male and one parasitic male, each kept inside a large tank provided with an artificial buried nest (always occupied by the territorial male) and one small tunnel-shaped shelter (always occupied by the small male), were observed during one-female spawning taking place in the innermost part of the nest (i.e. the nest chamber). During the spawning, the presence of the small male nearby the nest openings elicited aggressive behavior and increased nest patrolling by the territorial male. In one spawn the small male never attempted to enter the nest. In four spawns the small male entered one to three times the nest chamber (sneaks), staying there from 2 to 203 s until the large male chased him away. The temporal patterning of the spawning activity by the territorial male (bouts of upside–down, U–D), and its changes following a sneak by the small male, were investigated using bout analysis and correlative tests. Results showed the length of bouts U–D did not change significantly after a sneak intrusion. whereas gap length (i.e. the period between subsequent bouts U–D) decreased significantly after each sneak intrusion. The mean duty cycle of bouts U–D tended to be positively correlated to the number of sneaker intrusions of each replicate. Results are discussed in the light of current knowledge on sperm competition among externally fertilizing teleosts.     

Sex-specific differences in reindeer calf behavior and predation vulnerability

According to reproductive strategy theory, males in polygamousbreeding systems should invest in morphological or behavioralfeatures that increase reproductive success. When the earlydevelopment of such traits conflicts with predator protection,we expect that male calves will exhibit risk-taking behavior,such as high activity level and increasing distance from mother,to a greater extent than female calves. We investigated sexdifferences in mother–calf distance, calf activity levels,and calf mortality in a semi-domesticated reindeer (Rangifertarandus) population. The results show that male calves strayfarther away from their mothers, exhibit a higher level of locomotivebehavior in terms of play and walking, and are more vulnerableto predation than are female calves. Although mother–calfdistance increased over time in 1- to 6-month-old calves, noevidence was apparent for an increase in sex difference in mother–calfdistance over this period. The results suggest a trade-off betweenpredation vulnerability and investments in behavioral traitsthought to be important for future reproductive success andsuggest that these sex-related differences in behavior are apparentas early as 6 months of age.     

The Function of Mounting Behaviour in Farmed Red Deer Calves

The function of mounting behaviour was studied in farmed red deer (Cervus elaphus) calves. On the basis of previous work, we tested two alternative hypotheses about the function of this behaviour. The first hypothesis deals with the proximate function of the behaviour. Three predictions were tested: (1a) mounting behaviour attracts the attention of the mother and/or consolidates the mother–calf bond; (1b) mounting is intended to obtain more milk; (1c) mounting is intended to prevent other calves from sucking from the mother. The second hypothesis deals with an ultimate function in practising for future life with two predictions tested: (2a) mounting behaviour is part of calves' play behaviour promoting development of the calf's locomotor and social skills; (2b) calves gain sexual experience through mounting behaviour. For the study, 50 hind‐calf pairs were observed. The maternity of individual hinds was confirmed by a genetical analysis. The hinds were classified as ‘maternal’ and ‘non‐maternal’ and the calves as ‘filial’ and ‘non‐filial’. We recorded 40 cases of mounting behaviour involving 25 hinds and 21 calves. Our results suggest that the mounting behaviour of red deer calves serves several different functions depending on the circumstances. In association with suckling, calves of both sexes mounted maternal hinds mainly to attract their attention and to achieve another suckling. In situations not associated with suckling, mounting by male calves might be considered part of their sexual training. On the other hand, mounting by female calves probably reflects the attempt to maintain contact with their mother in tense situations.     

Suckling Behavior of the Collared Peccary (Tayassu tajacu)

Based on Trivers' (1974) theory of parent/offspring conflict, we predicted that weaning would be accelerated under poor dietary conditions in an aseasonally breeding, monomorphic ungulate, the collared peccary (Tayassu tajacu). Suckling behavior was observed in 18 captive litters under a dietary treatment of high or low protein formulated to mimic forage under ecological conditions of normal rainfall vs. drought. Litters on the low protein diet weaned later (mean of 27 weeks) than litters on the high protein diet (mean of 21 weeks). Other indices of cumulative suckling effort (weaning weight, cumulative minutes suckling, cumulative bouts) did not differ between dietary treatments. No differences in suckling effort were found relative to offspring sex or litter size. Milk did not completely compensate for the low protein diet affecting growth of young in the second and third phases of lactation. Some nursers did not conserve bodily resources as would be expected if the benefits of short interbirth intervals outweighed the costs of lactation during unpredictable drought conditions.     

Chinko/Mbari drainage basin represents a conservation hotspot for Eastern Derby eland in Central Africa

One of the largest of antelopes, Derby eland (Taurotragus derbianus), is an important ecosystem component of African savannah. While the western subspecies is Critically Endangered, the eastern subspecies is classified as least concern. Our study presents the first investigation of population dynamics of the Derby eland in the Chinko/Mbari Drainage Basin, Central African Republic, and assesses the conservation role of this population. We analysed data from 63 camera traps installed in 2012. The number of individuals captured within a single camera event ranged from one to 41. Herds were mostly mixed by age and sex, mean group size was 5.61, larger during the dry season. Adult (AD) males constituted only 20% of solitary individuals. The overall sex ratio (M:F) was 1:1.33, while the AD sex ratio shifted to 1:1.52, reflecting selective hunting pressure. Mean density ranged from 0.04 to 0.16 individuals/km², giving an estimated population size of 445–1,760 individuals. Chinko harbours one of the largest documented populations of Derby eland in Central Africa, making Chinko one of its potential conservation hotspots.     

Behavior of Japanese monkey (Macaca fuscata) mothers and neonates at parturition

Parturitional behavior in 12 caged Macaca fuscatawas analyzed. Wild-caught mothers showed adequate maternal behaviors immediately following the neonate’s expulsion. Parity differences existed in the behaviors; primiparae were more idiosyncratic than were multiparae. Among multiparae, those with two or more offspring were uniformly adequate, but those with a single birth experience varied in the adequacy of the maternal care they provided at parturition. Mothers embraced and licked their neonates and had ventroventral contact with them frequently immediately after parturition but decreased these behaviors after expulsion of the placenta. In contrast, mothers showed allogrooming after consuming the placenta. Placentophagy was correlated with the level of orality represented by maternal licking behaviors. An isolation-reared primipara reacted to her newborn in a basically negative manner, although she showed little actual aggression. She showed a rapid shift in her negative behavior during the immediate postpartum period. This mother’s newborn sought contact with her, indicating the neonate’s active role in establishing a stable mother-neonate bond.     

Dive bout organization in the Chinstrap penguin at seal island, antarctica

Diving behavior of 2 breeding Chinstrap penguins (Pygoscelis antarctica) was studied focusing first and primarily on dive bouts rather than dives themselves. Analysis of dive bout organization revealed (1) though there are differences between solitary dives and dive bouts in dive duration and dive depth, the first dives of dive bouts do not differ from solitary dives in the dive parameters, (2) mean dive duration during bout correlates positively to both mean dive depth during bout and mean surface interval during bout, while number of dives during bout negatively correlates to both cost (consumed energy) and duration of a dive cycle during bout. These findings suggest the following possibilities on foraging behavior of penguins: (1) their decision to repeat diving depends on the result of the first dive at a site, and the first dives of bouts would tend to be searching or evaluating dives though they would be also successful foraging dives, (2) they repeat diving at a foraging patch until foraging efficiency decrease to a threshold of diminishing returns.     

Population genetic structure of wild and farmed rusa deer (<Emphasis Type="Italic">Cervus timorensis russa</Emphasis>) in New-Caledonia inferred from polymorphic microsatellite loci

Historical records indicate that 12 rusa deer (Cervus timorensis russa) were introduced in New-Caledonia during the 1870s. We used eight polymorphic microsatellite DNA loci to assess the genetic differentiation and diversity of farmed and wild deer populations. Past genetic bottlenecks were detected in both sub-populations, although higher genetic diversity was maintained in farmed populations, probably due to the regular introduction of reproducers from wild populations and from other farms. The genetic structure of farmed and wild populations differed significantly. There was a significant isolation by distance for wild populations, whereas farmed populations were significantly differentiated between farms independently from their geographical proximity. Wild rusa deer consisted of small populations (with effective population sizes ranging between 7 and 19 individuals depending on the methods used), with a low parent–offspring dispersion range (0.20–2.02 km). Genetic tools and direct observations provided congruent estimates of dispersion and population sizes. We discuss the relevance of our results for management purposes.