Do female degus communally nest and nurse their pups?

We examined the nesting and nursing behavior of females of the caviomorph rodent Octodon degus. We recorded the behavior of two, three-female groups of lactating degus kept in captivity and compared it with that of singly housed lactating females. Grouped females spontaneously nested communally. Five of six lactating females had non-offspring pups hanging from their teats, which suggests that some non-offspring nursing took place. Non-mothers increased their maternal behavior after the delivery of their own pups. Although time allocated to parental care by each communally nesting dam did not differ from that of solitary lactating females, young of communal litters spent less time alone and enjoyed more time cared for by a lactating female than young of single dams. Electronic Publication     

Competitive interactions between spotted hyenas and lions in the Etosha National Park, Namibia

Spotted hyenas are successful hunters, but they also scavenge. Their main food competitors are lions. In the Etosha National Park, Namibia hyenas are unable to prevent kleptoparasitism by lions and fail to acquire kills from lions. The reasons are the small ratio of hyenas to female and subadult lions at kills and the presence of adult male lions. Because of the hyenas’ small clan sizes and large territories they seem to be unable to recruit sufficient clan members to take over lion kills or deter lions from their own kills. In Etosha, 71% of hyena mortality was due to lions; four cubs and one adult female hyena were killed by male lions during a 1‐year study. Hyenas have evolved adaptations against lions and initiate aggressive interactions with lions without the immediate availability of food, which is termed mobbing behaviour. Etosha hyenas initiated mobbing attempts when lions were near the hyena's communal den. Possibly, Etosha hyenas mobbed lions to distract lions from the hyenas’ den and their cubs and to warn their dependent offspring to hide from lions.     

A case of co-operative nursing and offspring care by mother and daughter feral horses

Among mammals, non-offspring nursing is the most extreme form of communal parenting. This is because lactation is the most energetically costly part of parental investment (Clutton-Brock, 1991; Packer, Lewis & Pusey, 1992). Non-offspring nursing is most common in species characterized by large litters and small kin groups (Packer et al ., 1992; e.g. lions Panthera leo : Pusey & Packer, 1994). Although non-offspring nursing has also been reported in monotocous species (e.g. water buffalo Bubalus bubalus , Murphey et al ., 1995; African elephant Loxodonta africana : Dublin, 1983; Lee, 1987; Indian elephant Elaphus maximus : MacKay, 1973; Rapaport & Haight, 1987; fallow deer Cervus dama : San José & Braza, 1993) it is almost always associated with reproductive errors (Riedman, 1982) such as milk theft or exclusive adoption (Packer et al ., 1992). However, simultaneous non-offspring nursing in monotocous species has been reported in some bat species (e.g. McCracken, 1984; Eales, Bullock & Slater, 1988), African elephants (Lee, 1987), and captive Indian elephants (Rapaport & Haight, 1987). Recent research, however, suggests that nutritive non-offspring nursing in African elephants is rarer than previously thought as most reported instances were probably non-lactating juveniles allowing infants to suckle (Lee & Moss, 1986; Lee, 1987, 1989).     

Infanticide by Male Lions Hypothesis: A Fallacy Influencing Research into Human Behavior

Recently, familial abuse and killing of children have been correlated with infanticidal behavior by nonhuman male animals which is postulated to be genetic. However, infanticide by males as an evolutionary mechanism is unlikely to occur in primates, and is equally unlikely in lions. To investigate the sexual selection hypothesis of infanticide for lions, four questions should be considered: (1) because they all mate freely with lionesses, are male pride lions closely related? (often they are not), (2) do males kill the young cubs when they join a pride? (few such cases have been observed), (3) do the females then mate with the new males to produce offspring? (yes), and (4) do the males remain with the pride for over two years to protect this new generation? (often not). Field data indicate that in NO instance do we know that male lions killed cubs in a new pride, mated with their mother, and then remained with the pride to protect their own young. Rather, female lions may kill more cubs than males and certainly cause many more cub deaths by allowing them to starve, [ infanticide by male lions, infanticide hypothesis, faulty science]     

Allonursing in Captive Guanacos,Lama guanicoe: Milk Theft or Misdirected Parental Care?

Females in several ungulates transfer milk to non-filial (NF) offspring, in a process known as allonursing. This behavior is less common in monotocous species, including most ungulates, and it has been associated with parasitic behavior of calves or mothers who have lost their own offspring. To examine whether the calves 'steal' milk from the females or whether females fail to discriminate their own calves in guanacos, allonursing behavior was observed. If milk theft drives allonursing, mothers should reject NF offspring, they should search for their own calves, and calves attempting to suckle from alien mothers should adopt parallel (as opposed to the anti-parallel) position during allonursing. Alternatively, if allonursing is caused by mothers unable to discriminate own offspring, mothers are not expected to reject NF offspring, and alien calves should use parallel and antiparallel position similarly when allonursing. Allonursing was investigated during the first 3 mo of lactation in two groups of captive guanacos composed of 15 and 14 mother-calf pairs, respectively. While 40% and 62.5% of mothers in groups 1 and 2 performed allonursing, high individual variation prevailed; some females exhibited this behavior infrequently (4.1% and 6.5 % in groups 1 and 2). The rejection rate to NF nursing attempts was threefold higher than the rejection rate to filial nursing attempts. The occurrence of nursing to NF was associated to a parallel posture by the calves. Our findings suggest that 'milk theft' is a more plausible hypothesis to explain allonursing in guanacos than 'misdirected parental care'.     

Maternal rank is not correlated with cub survival in the spotted hyena, Crocuta crocuta

Reproductive success in female spotted hyenas, Crocuta crocuta,is positively correlated with social rank. High-ranking femalesare known to produce more offspring, but the effects of maternalrank on early cub survivorship have not been investigated. Cubmortality was examined over a 4-year period in one clan of wild-livingspotted hyenas in Kenya. Data were obtained for 100 cubs in63 litters produced by 27 adult females. Survivorship of cubsfrom birth through their first year was examined as a functionof litter size, sex of cubs, and maternal rank. Overall, cubmortality was high (61%). Contrary to expectation, singletoncubs did not survive better than twins, and there was no differencein survivorship between female and male cubs. High-ranking motherswere not more successful at raising twins or daughters thanwere low-ranking mothers. There was no correlation between cubmortality and maternal rank. Peaks in cub mortality coincidedwith life stage events, including mean age of arrival at a communalden, and age at which cubs began visiting kills. Documentedcauses of mortality included intraclan infanticide, disease,orphaning, predation by lions, and a mechanism of filial infanticidethat has not been previously described in this species: selectivelitter reduction by mothers via partial litter abandonment.No instances of facultative or obligate siblicide were detected.During this study, association between rank and number of cubssurviving to 1 year of age appeared to be due to differencesin reproductive output and not differential survival of cubswithin their first year.     

Non-offspring nursing by a nulliparous pregnant female just before first parturition in free-ranging Japanese macaques

A nulliparous pregnant Japanese macaque, Macaca fuscata, suckled her 1-year-old sister 44 days before her own parturition. Other Japanese macaque yearlings did not hold the nipples of this nulliparous female in their mouths. Although this non-offspring nursing before first parturition did not improve the rate of milk secretion, the nulliparous female may have improved her indirect fitness and her suckling behavior.     

Polygynandry in a red fox population: implications for the evolution of group living in canids?

Canid social groups are typically thought to consist of extendedfamilies, that is, a dominant breeding pair and related nonbreedingsubordinates, that principally obtain indirect fitness benefitsfrom helping to raise the offspring of the dominant pair. Consequently,the monogamous pair has been viewed as the basic fundamentalunit of canid social organization. However, there have beenfew genetic studies that have tested this assumption. We analyzedthe parentage of red foxes (Vulpes vulpes) in a high-density(19.6–27.7 adult foxes/km²) population in Bristol, UK,to determine (1) whether groups typically produced a singlelitter of cubs annually and (2) whether male and female foxesexhibited monogamous mating strategies. Social monogamy (theproduction of one litter in a social group) was observed orassumed in 54% of breeding attempts (N = 13 group-years). However,polyandrous and polygynous patterns of mating were common. Multiplepaternity was confirmed in 38% of litters (N = 16) containingoffspring with resolved maternity and paternity (N = 30 cubs);when including cubs with unresolved paternity (N = 20), multiple-paternitymay have occurred in 69% of litters. Litters were sired by anaverage of 1.6 identified males (range = 1–4); when includingcubs with unresolved paternity, litters may have been siredby up to seven males. Only 20% (6/30) of cubs with resolvedmaternity and paternity were sired by males within the socialgroup. Within groups, dominant females did not breed with subordinatemales; dominant males did breed with subordinate females. Dominantand subordinate females both produced cubs with dominant andsubordinate males from other social groups. Mean adult relatednessin groups typically ranged from 0.15–0.35, indicativeof second-order rather than first-order relatives.     

High Natality Rates of Endangered Steller Sea Lions in Kenai Fjords,Alaska and Perceptions of Population Status in the Gulf of Alaska

Steller sea lions experienced a dramatic population collapse of more than 80% in the late 1970s through the 1990s across their western range in Alaska. One of several competing hypotheses about the cause holds that reduced female reproductive rates (natality) substantively contributed to the decline and continue to limit recovery in the Gulf of Alaska despite the fact that there have been very few attempts to directly measure natality in this species. We conducted a longitudinal study of natality among individual Steller sea lions (n = 151) at a rookery and nearby haulouts in Kenai Fjords, Gulf of Alaska during 2003–2009. Multi-state models were built and tested in Program MARK to estimate survival, resighting, and state transition probabilities dependent on whether or not a female gave birth in the previous year. The models that most closely fit the data suggested that females which gave birth had a higher probability of surviving and giving birth in the following year compared to females that did not give birth, indicating some females are more fit than others. Natality, estimated at 69%, was similar to natality for Steller sea lions in the Gulf of Alaska prior to their decline (67%) and much greater than the published estimate for the 2000s (43%) which was hypothesized from an inferential population dynamic model. Reasons for the disparity are discussed, and could be resolved by additional longitudinal estimates of natality at this and other rookeries over changing ocean climate regimes. Such estimates would provide an appropriate assessment of a key parameter of population dynamics in this endangered species which has heretofore been lacking. Without support for depressed natality as the explanation for a lack of recovery of Steller sea lions in the Gulf of Alaska, alternative hypotheses must be more seriously considered.     

Habitat use and movements of plains zebra (Equus burchelli) in response to predation danger from lions

Prey species must adapt their behavior to avoid predation. Asa key prey item for lions (Panthera leo), plains zebras (Equusburchelli) were expected to respond to immediate threats posedby lions in their area. In addition, zebras were predicted toexhibit behavior tuned to reduce the potential for encounterswith lions, by modifying their movement patterns in the timesof day and habitats of greatest lion danger. We studied a populationof approximately 600 plains zebra living in Ol Pejeta Conservancy,Kenya. We found that zebra abundance on or near a grasslandpatch was lower if lions had also been observed on that patchduring the same day. Predation danger was highest in grasslandhabitat during the night, when lions were more active. Zebrasightings and global positioning system radio collar data indicatedthat zebras also reduced their use of grassland at night, insteadusing more woodland habitat. Zebras moved faster and took sharperturns in grassland at night. It is hypothesized that these moreerratic movements assist zebras in avoiding detection or captureby lions.     

哺乳期圈养雌性大熊猫圈舍转移及其育幼行为变化

<正>大熊猫(Ailuropoda melanoleuca)为我国特有珍稀濒危物种之一,被誉为"国宝"。经过科研人员多年努力,圈养大熊猫"配种难、受孕难、幼仔存活难"等问题已基本被成功解决,圈养大熊猫种群数量正在快速增加(张和民等,2013)。目前我国已经建立了四川卧龙、成都和陕西楼观台3个较大的圈养大熊猫种群繁育基地。截至2013年底,圈养大熊猫种群数量已经达到375只(谢钟,2013)。快速增加的圈养种群,导致现存可供使用     

大熊猫母兽可根据幼仔的尖叫声辨别自己的后代

研究表明,群居哺乳动物具备通过叫声进行母幼识别的机制,而有关独栖动物的母幼识别机制鲜有研究。大熊猫(Ailuropoda melanoleuca)是典型的独栖动物,原始森林是保持野生大熊猫种群数量可持续发展的必要条件,其中的大型古树提供的育幼巢穴对大熊猫幼仔的存活至关重要。但是,近年来大型古树因受人为干扰而急剧减少,致使野生成年雌性大熊猫活动领域的重叠增大,在育幼期产仔大熊猫母兽对育幼巢穴的利用产生了竞争。大熊猫幼仔的体重约为成年大熊猫的0.1%,幼仔需要母兽高度关怀才能存活和成长。叫声是0-45日龄大熊猫幼仔向其母兽传递生理需求或所处状态的主要方式。然而,母兽能否根据幼仔的叫声识别自己的后代,目前尚无定论。本研究以274条大熊猫幼仔的尖叫声为例,首先对其进行个体独特性分析,然后通过叫声回放以及母兽对所回放的两种叫声的行为反应,验证大熊猫母兽能否辨别出其亲生幼仔。结果发现,尖叫声的17个声学参数中有14个具有潜在的个体判别能力(PIC>1);进一步的判别分析结果显示,基于这17个声学参数,78.5%的尖叫声被正确分配到对应的幼仔;叫声回放实验的结果显示,母兽在行为上更倾向其亲生幼...     

Nursing Synchronization and Milk Ejection Failure as Maternal Strategies to Reduce Allosuckling in Pair-Housed Sows (Sus scrofa domestica)

Non‐offspring nursing (allosuckling) is costly for lactating females. It is reasonable to assume, therefore, that mechanisms have evolved to control the frequency of allosuckling. It is suggested that the synchronization of nursing between females could be such a mechanism. The aim of this study was to investigate whether nursing synchronization is related to the timing of nursing behaviour of paired sows and the behaviour of alien piglets in relation to allosuckling. Specifically, we predicted that: (i) nursing synchronization will increase if there is a real risk of allosuckling compared with a situation where there is none, (ii) nursing synchronization indeed reduces allosuckling and, therefore, those nursings with allosuckling attempts will be less closely synchronized than those without allosuckling attempts and (iii) in non‐synchronized nursings, the sows will more often employ another strategy to reduce allosuckling, namely, they will make the nursings non‐nutritive by not releasing milk. Ten pairs of sows and their litters were used in this study. For each pair, the two sows were housed individually until their litters were weaned; however, their litters had access to both sows from day 11 post‐partum. The behaviour of the 10 pairs of sows with their litters was videotaped for 6 h on days 10, 11, 17 and 24 post‐partum. The frequency of allosuckling attempts, non‐nutritive nursings and allosuckling during milk ejection was analysed for every pair for every day of observation. The observed frequency of nursing synchronization was high. The median interval between the start of a nursing within one pair of sows was 32 s. The first prediction was supported as synchronization became significantly tighter when piglets were given the possibility to allosuckle on day 11 [Cochran–Mantel–Haenszel (CMH) statistics, p < 0.0001]. The second prediction was also supported; the nursings were less closely synchronized when there were allosuckling attempts (CMH statistics, p < 0.05). Of all nursings, 36% had an allosuckling attempt; however, only 17% resulted in real allosuckling. Evidence in favour of the third prediction was also found as non‐nutritive nursings were more frequent in non‐synchronized nursings (CMH statistics, p < 0.05). Finally, real allosuckling during milk ejection was unrelated to the degree of nursing synchronization, as in less synchronized nursings, the sows responded to allosuckling attempts by not releasing milk. Our results suggest that sows are not able to completely suppress allosuckling; however, they can reduce its frequency through nursing synchronization and non‐nutritive nursings.     

Lion density and population structure in the Selous Game Reserve: evaluation of hunting quotas and offtake

In 1992, tourist hunting in the Selous Game Reserve generated 1.28 million dollars for the Tanzanian government, of which 0·96 million dollars were returned to wildlife conservation. Lions ( Panthera leo ) are one of three critical species for tourist hunting, consistently generating 12%–13% of hunting revenue from 1988 to 1992. Because of their ecological and economic importance (and intrinsic value), it is important that lion quotas be set so that offtake is sustainable. The population density of lions in Selous ranges from 0·08 to 0·13 adults km⁻², comparable to unhunted ecosystems. The adult sex ratio (36–41% male) and the ratio of cubs to adults (29% cubs) are similar to those of unhunted populations. The ratio of lions to hyaenas is lower in heavily hunted areas (0·17 lions/hyena) than in unhunted areas (0·43 lions/hyena). Hunting levels between 1989 and 1994 took 2·7–4·3% of adult males annually, which is sustainable. The current quota is 10–16% of the adult male population, which exceeds natural mortality rates for male lions. To remain stable if the quota was filled, the population would have to compensate via increased fecundity, increased juvenile survival, or an altered sex‐ratio. Compensation occurs in Selous by producing (or raising) more male than female cubs (66–81% of juveniles are male). Only 28% of the Selous quota was filled in 1992. The percentage of quota filled (both in Selous and nationwide) has dropped since 1988 as quotas have increased. The current intensity of lion hunting in Selous is sustainable, but the quota cannot be filled sustainably.     

The number of subordinates moderates intrasexual competition among males in cooperatively breeding meerkats

For dominant individuals in cooperatively breeding species, the presence of subordinates is associated with both benefits (i.e. increased reproductive output and other group-living benefits) and costs (i.e. intrasexual competition on reproduction). The biological market theory predicts that dominant individuals are tolerant to same-sex group members when there are only a few subordinates, so as to maximize their own reproductive success. We investigated factors affecting aggression by dominant males and submission by subordinate males for a cooperatively breeding mammal, meerkats, Suricata suricatta. In this species, reproductive conflict occurs between the dominant male and the non-offspring males. As predicted, the number of subordinates in a group was positively associated with the aggression frequency by the dominant male and with the submission frequency by the subordinate males. Relative to the aggression frequency against male offspring, the frequency of aggression against non-offspring males was comparable in small groups, but was higher in large groups. These results indicate that reproductive conflict is present between the dominant male and the non-offspring males but is moderated in groups with small numbers of subordinates. This study provides an empirical data agreeing with the biological market theory in the context of intrasexual competition in cooperatively breeding species.     

Lethal combat and sex ratio evolution in a parasitoid wasp

Sex allocation theory provides excellent opportunities for testinghow behavior and life histories are adjusted in response toenvironmental variation. One of the most successful areas fromthis respect is Hamilton's local mate competition theory. Aspredicted by theory, a large number of animal species have beenshown to adjust their offspring sex ratios (proportion male)conditionally, laying less female-biased sex ratios as the numberof females that lay eggs on a patch increases. However, recentstudies have shown that this predicted pattern is not followedby 2 parasitoid species in the genus Melittobia, which alwaysproduce extremely female-biased sex ratios. A possible explanationfor this is that males fight fatally and that males producedby the first female to lay eggs on a patch have a competitiveadvantage over later emerging males. This scenario would negatethe advantage of later females producing a less female-biasedsex ratio. Here we examine fatal fighting and sex ratio evolutionin another species, Melittobia acasta. We show that femalesof this species also fail to adjust their offspring sex ratioin response to the number of females laying eggs on a patch.We then show that although earlier emerging males do have anadvantage in winning fights, this advantage 1) can be reducedby an interaction with body size, with larger males more likelyto win fights and 2) only holds for a brief period around thetime at which the younger males emerge from their pupae. Thissuggests that lethal male combat cannot fully explain the lackof sex ratio shift observed in Melittobia species. We discussalternative explanations.     

人工育幼非洲狮、孟加拉虎、豹幼仔的生长曲线拟合比较

<正>生长曲线(Growth curve)是揭示动物生长发育规律的有效手段之一，反映动物发育指标(包括体重、体尺、体表面积等度量值)与时间之间的关系(盛志廉和吴常信，1995)。生长曲线方程大致可以分为三类：第一类是表示报酬递减规律的方程，如指数函数；第二类是描述光滑S型曲线，     

Monandry and polyandry as alternative lifestyles in a butterfly

Butterflies show considerable variability in female mating frequency, ranging from monandrous species to females mating several timesin their lifetime. Degree of polyandry also varies within species,with some females only mating once and others mating multiply.Previous studies have shown that one reason for female multiplemating is to obtain nutritious male donations that both increasethe longevity of females and result in higher lifetime fecundity.Despite the presence of male nutrient donations, some femalesof the green-veined white butterfly (Pieridae: Pieris napi)never mate more than once. In this study, we examined thisapparent paradox. We assessed to what degree polyandry is undergenetic control by a full-sib analysis, and we also estimatedthe broad sense heritability of female lifetime fecundity in singly mated females. Both polyandry and lifetime fecundityhave a genetic component. However, degree of polyandry appearsto be traded off against reduced longevity when denied theopportunity to mate more than once. It is possible that femaleP. napi display different reproductive strategies, with somefemales relying on male donations to realize their potentialfecundity and others relying on their own resources for egg production. In nature, polyandrous females may be preventedfrom mating multiply due to unfavorable weather. We discussthe possibility that the trade-off between degree of polyandryand life span when singly mated may affect the maintenanceof genetic variability in female mating frequency in this species.Possible reasons for these different reproductive strategiesare discussed.     

Eavesdropping and Risk Assessment Between Lions,Spotted Hyenas and African Wild Dogs

Vocalizing allows rapid transmission of detailed information beyond line of sight. However, the risk of eavesdropping by unintended receivers means there is also a potential cost to any vocalization. For fugitive species such as African wild dogs the potential cost of attracting dangerous competitors as eavesdroppers is especially significant. Experiments presented here demonstrate that eavesdropping lions Panthera leo were highly motivated to approach playbacks of wild dog Lycaon pictus vocalizations. As lions will kill any wild dogs they can catch, wild dogs risk paying high costs should their calls be detected. Lions were less likely to approach playbacks of spotted hyena Crocuta crocuta whoops, with responses split according to gender: male lions remained quick to approach hyena whoops, but females without accompanying males typically did not approach. Although hyenas seemed at least as capable as lions of detecting playbacks of wild dog calls, they were significantly less likely to subsequently approach them. Analogous to female lions faced with hyenas, the reluctance of hyenas to approach wild dogs may well derive from an assessment of the potential risks involved. We consider the hypothesis that wild dog twitters display counter‐adaptations against eavesdropping, but suggest that this species may best limit the risk of detection by avoiding areas where they are most likely to be overheard by lions.     

南非Hluhluwe-Umfolozi公园植被对非洲狮群大小的影响

非洲狮(Pantheraleo)群处于不断的分裂-聚合过程,其亚群大小与原狮群大小以及诸如狮群捕食成功度、协作幼仔保护及狮群领域防卫等社会性因素有关。我们分析了南非一个保护区(Hluhluwe-Umfolozi公园)15年间的狮群大小,其成年雌狮和成年雄狮群的大小在保护区内呈显著性变化。在开放生境中雌狮结大群,而茂密植被生境中则结小群。雄狮群大小与植被类型无关,但在大的雌狮群分布区域发现大雄狮群。令人惊奇的是,作为幼狮成活率指标的幼狮群大小和雌狮平均幼仔数在保护区内没有显著性差异。我们认为,雌狮群大小的不同是对植被结构的适应,即在开放生境中大群有利于协作狩猎、育幼、共同保护幼仔、应对高强度群间领域防卫竞争。相反,茂密植被中,群间竞争很低,高密度植被覆盖有利于狩猎成功及补偿小狮群对幼仔保护的不足。雌狮平均幼仔数在整个保护区内没有变化,我们认为是由于开放生境和茂密植被对狮群大小起到相似的调节作用