Absence Of Pups Research Articles

Function of meerkats' mobbing-like response to secondary predator cues: recruitment not teaching

Early detection of predators greatly improves prey escape and survival chances. By investigating cues predators leave behind, such as fur, urine, faeces or feathers (secondary predator cues), prey may gain vital information about predators in the vicinity. Meerkats, Suricata suricatta , display an unusual mobbing-like response upon encountering secondary predator cues, not reported in any other species. The function of this behaviour is unclear because, unlike mobbing of a live predator, it cannot yield the primary benefit of driving the threat away. Here we examine two potential functions. First, we hypothesized that older group members may exhibit exaggerated mobbing-like responses towards secondary predator cues as a form of teaching to promote learning in naïve pups. Meerkats are known to teach pups hunting skills, but there is no evidence that any nonhuman species teaches across multiple contexts. Mobbing-like responses could also function to facilitate group member recruitment, stimulating information gathering and collective decision making by the group. Using experimental presentations of secondary predator cues in the presence and absence of pups, in combination with 20 years of data on natural encounters with secondary predator cues, we found that older group members' response frequency was lower when pups were present and that response intensity declined as the proportion of pups to total group member number increased. Conversely, the intensity of responses increased when a greater proportion of group members interacted with the cue and varied with predator cue type. The response frequency to natural encounters with secondary predator cues was greater in larger groups, and the distance travelled by the group decreased following an encounter with secondary predator cues. These results suggest that meerkats do not show exaggerated responses to secondary predator cues as a form of teaching. Mobbing-like responses more likely serve to increase recruitment of others to investigate the cue and inform defensive group behaviour. • Meerkats show an unusual mobbing-like response to secondary predator cues (SPCs). • We examined potential functions using cue presentations and long-term observations. • No evidence to support teaching via increased mobbing-like response in pup presence. • Large groups responded to SPCs more often; distance travelled fell after encounters. • Mobbing-like response facilitates recruitment and informs group defensive behaviour.

Repeated predator odor exposure alters maternal behavior of postpartum Brandt’s voles and offspring’s locomotor activity

Recent evidence indicates that predation risk plays a special role in the rodent behavior of dams and offspring, but little is known about the effect of maternal exposure to the predator cues in the absence of pups. Here, we assessed the effects of repeated predator odor exposure on various maternal responses in postpartum Brandt’s voles (Lasiopodomys brandtii). We also examined offspring’s behavioral response to a novel environment. Only mother voles were exposed to distilled water, rabbit urine and cat urine for 60 min daily from postpartum day (PP) 1–18. Maternal behavior was immediately tested after these exposures on PP1, 3, 6, 9 and 18. Repeated cat odor (CO) and rabbit odor (RO) exposure disrupted hovering over pups in a time-dependent fashion. Repeated CO exposure also time-dependently disrupted pup retrieval, whereas RO exposure induced long-term reduction in pup licking. Juvenile offspring of CO-exposed mothers showed increased locomotor activity and decreased rearing in the open field at postnatal day 30. These findings demonstrated that maternal exposure to predator or non-predator odors had a disruptive effect on the maternal behavior of Brandt’s voles when only the mother was exposed to these odors, and that the adversity experience with predation risk significantly impacted the behavioral development of offspring. Future work should explore possible behavioral mechanisms, such as the effect of predation risk, on the dams’ emotional processing or pup preference.

Who let the dogs out? Occurrence, population size and daily activity of domestic dogs in an urban Atlantic Forest reserve

Domestic dogs (Canis lupus familiaris) are one of the most common exotic species in protected areas, and their impact is an important conservation concern. This study evaluated the occurrence of domestic dogs in one of the world's largest urban forests, the Tijuca National Park (TNP; 3953ha), the most visited Park in Brazil. From April to September 2016, 42 camera-trap stations, spaced 0.5km among them, were set in TNP, covering an area of 1050ha. Population size and density of dogs were estimated, and the spatial distribution of dogs evaluated in relation to the distance to the Park's boundaries and to paved roads. Dogs’ circadian activity pattern and its overlap with those of the five most recorded native mammal species were also studied. The estimated population size of dogs was 29±4.86 (mean±SE) individuals, and the estimated density was between 0.74ind./km2 and 1.37ind./km2. Domestic dogs were widely distributed in the Park, and the number of independent dog records was not related to proximity to paved roads or the boundaries of the Park. The domestic dog was mainly diurnal in TNP, overlapping its activity mostly with the red humped agouti Dasyprocta leporina and the coati Nasua nasua. The absence of pups indicates that dogs come from surrounding areas rather than being a feral population within TNP. Therefore, managing strategies must consider the engagement of local people.

No evidence for punishment in communally nursing female house mice (Mus musculus domesticus).

Punishment is claimed as an important mechanism to stabilise costly cooperation in humans, but its importance in social animals has been questioned recently due to both conceptual considerations and a lack of empirical evidence (only few published studies). We empirically tested whether there is evidence for punishment in communally nursing house mice (Mus musculus domesticus, direct descendants of “wild” animals). Communally breeding females pool their litters and raise all offspring together, indiscriminately caring for own and other offspring. Such a situation resembles a public good and provides scope for exploitation if females vary in their relative contributions to the joint nest (offspring number). We allowed two females to communally breed and conducted removal experiments both in the presence and absence of pups. We aimed to test whether reduced investment by one of the females (induced through separation from the partner and their combined offspring for 4 or 12 hours) leads to increased aggression by the other female after the reunion. We found no evidence for punishment, on the contrary, females increased socio-positive behaviours. The costs of losing a partner in a communally breeding species might be too high and hinder the evolution of punishment. Our findings add to a growing list of examples questioning the role of punishment in cooperating non-human animals and emphasise the importance of empirical testing of its assumptions and predictions.

Absence epileptic activity in Wistar Albino Glaxo Rijswijk rat mothers

Absence epileptic activity was analyzed during pregnancy, the postpartum period and after weaning to establish alterations of seizures throughout the reproductive cycle. Wistar Albino Glaxo Rijswijk (WAG/Rij) rats were used in the study as a model of absence epilepsy and because their seizures do not interfere with rearing offspring. The number of spike-wave discharges (SWDs) was gradually elevated from the 19th pregnancy day to delivery. Meanwhile, the characteristics of individual SWDs did not change suggesting that SWD generation remained the same. In the postpartum and postweaning periods, the number of SWDs was not increased in the absence of pups. However, returning the pups to mothers resulted in a markedly elevated number of SWDs for 1h. If pups were taken away after 30min, the number of SWDs dropped immediately suggesting that the presence of pups increased the SWD number. The time mothers spent with the litter and in kyphosis suckling posture were in correlation with their SWD number further suggesting the importance of interaction with pups in SWD induction. Suckling elevates prolactin levels but surprisingly, its intracerebroventricular injection markedly reduced SWD number in suckled WAG/Rij mothers suggesting that the SWD-inducing effect of suckling is not mediated by prolactin. Rather, the elevated prolactin level may provide some protection against pro-epileptic effects of suckling. In conclusion, we first identified periods within the reproductive cycle with increased absence epileptic activity, implying that more attention should be devoted to epileptic activity changes in mothers.

Cocaine-associated odor cue re-exposure increases blood oxygenation level dependent signal in memory and reward regions of the maternal rat brain

BackgroundCue triggered relapse during the postpartum period can negatively impact maternal care. Given the high reward value of pups in maternal rats, we designed an fMRI experiment to test whether offspring presence reduces the neural response to a cocaine associated olfactory cue. MethodsCocaine conditioned place preference was carried out before pregnancy in the presence of two distinct odors that were paired with cocaine or saline (+Cue and −Cue). The BOLD response to +Cue and −Cue was measured in dams on postpartum days 2–4. Odor cues were delivered to dams in the absence and then the presence of pups. ResultsOur data indicate that several limbic and cognitive regions of the maternal rat brain show a greater BOLD signal response to a +Cue versus −Cue. These include dorsal striatum, prelimbic cortex, parietal cortex, habenula, bed nucleus of stria terminalis, lateral septum and the mediodorsal and the anterior thalamic nucleus. Of the aforementioned brain regions, only the parietal cortex of cocaine treated dams showed a significant modulatory effect of pup presence. In this area of the cortex, cocaine exposed maternal rats showed a greater BOLD activation in response to the +Cue in the presence than in the absence of pups. ConclusionsSpecific regions of the cocaine exposed maternal rat brain are strongly reactive to drug associated cues. The regions implicated in cue reactivity have been previously reported in clinical imaging work, and previous work supports their role in various motivational and cognitive functions.

Blood oxygen level‐dependent signal responses in corticolimbic ‘emotions’ circuitry of lactating rats facing intruder threat to pups

Lactating rats must continuously maintain a critical balance between caring for pups and aggressively responding to nest threats. We tested the neural response of lactating females to the presentation of their own pups and novel intruder males using blood oxygen level-dependent functional magnetic resonance imaging at 7 T. Dams were presented with a single sequence of a control stimulus, pups or a male intruder in one imaging session (n = 7-9). To further determine the selectivity of neural processing, dams were imaged for their response to a male intruder in both the absence and presence of their pups (n = 6). Several maternal cortical and limbic brain regions were significantly activated by intruder presentation but not by pups or a control stimulus. These included the nucleus accumbens, periaqueductal gray, anterior cingulate, anterior thalamus, basal nucleus of the amygdala, temporal cortex, prelimbic/orbital area and insula. The nucleus accumbens, periaqueductal gray, temporal cortex and mediodorsal thalamus still showed greater neural activity when compared with intruder presentation in the absence of pups. The present results suggest that the high emotional state generated by a threat to pups involves robust activation of classical limbic regions controlling emotional responses. This pattern of blood oxygen level-dependent activity may precede behavioral states upon which lactating rats initiate attacks against a potential threat to offspring.

Nursing stimulation is more than tactile sensation: It is a multisensory experience

Novel sensory experiences, particularly those associated with epochal developmental events like nursing alter cortical representation, affecting memory, perception and behavior. Functional MRI was used here to test whether the sensoricortical map of the ventrum is modified during lactation. Three stimuli were used to drive cortical activation in primiparous rats: natural, artificial suckling stimulation and general mechanical rubbing of the skin of the ventrum. These stimuli significantly activated the somatosensory cortex of dams. Of the three stimuli, artificial and pup suckling robustly activated much of the cerebrum, most notably the visual, auditory and olfactory cortices. Surprisingly, activation occurred even in the absence of pups, with artificial suckling. This finding suggests that incoming information from a single modality was sufficient to drive activity of others. Enhanced sensitivity across the cortical mantle during nursing may help the dam to perceive, process, and remember stimuli critical to the care and protection of her young.

The timing of pupping by pack-ice seals in East Antarctica

Data on the timing of pupping by the three species of phocid that breed on the Antarctic pack-ice (crabeater, Ross and leopard seals) are limited. Better information would improve our understanding of these species' population and reproductive ecologies, and could facilitate planning and design of population surveys. Observations of the presence or absence of pups with adults during numerous voyages of the Australian National Antarctic Research Expeditions to East Antarctica during spring and early summer months are analysed and presented. The earliest sighting in any year of a crabeater pup accompanied by an adult was on 2 October and the latest sighting on 15 December. The ratio of crabeater pups to adults increased rapidly during the 10-day period 16–25 October, implying a pulse of births over this time. Ross seal pups with an accompanying adult were sighted between 24 October and 22 November, with a peak in the pup-adult ratio occurring in the period 6–15 November. Leopard seal pups were sighted between 8 November and 25 December, with the pup-adult ratio relatively constant during this period. The data provide circumstantial evidence that the maximum durations of lactation reported in the literature for the three species may be over-estimates. If lactation is shorter than reported, asynchrony in the timing of pupping, either among or within years, is implied.

Rat pups are reinforcing to the maternal rat: Role of sensory cues

The present studies were undertaken to investigate the involvement of sensory cues in the expression of maternal behaviors and in the reinforcing properties of pups, reflected in performance on a conditioned place preference task. Postpartum animals were either able to interact with pups in one of two novel environments or were prevented from doing so by placing pups in a perforated Plexiglas cube. On alternate days, mothers were exposed to a second environment in the absence of pups. When the mothers tested for the development of a conditioned place preference, it was found that the group permitted pup interaction preferred the pup-paired box and that the no-interaction (distal) group did not. The role of the primary olfactory system was investigated by rinsing the nares of animals with either a 5% zinc sulphate spray to render the animal hyposmic or an air control and then permitting the animals to interact with pups in one of two novel environments. There were no differences between groups in maternal responding. However, when the mothers were tested for the development of a preference for the pup- paired box, it was found that while the air control animals preferred the pup-paired box, the anosmic zinc sulphate animals did not. To investigate the involvement of somatosensory cues, the ventral or perioral surfaces of animals were treated with either an anesthetic cream or a control cream prior to exposure to pups. Testing for maternal behaviors revealed that there were no differences between anesthetized groups and their controls. However, when the animals were tested for the development of a conditioned place preference, it was found that while both the ventral and perioral control groups preferred the pup-paired box, the ventral and the perioral anesthetized groups did not. Taken together, these studies demonstrate that several modalities involved in the interaction between pups and mothers contribute to the pups’ ability to be a reinforcing stimulus to the mother. The stimulation that postpartum mothers receive via these modalities is complex, and the disruption of any of them can alter the reinforcing capabilities of pups.

Rat pups are potent reinforcers to the maternal animal: Effects of experience, parity, hormones, and dopamine function

These experiments were designed to determine whether the parity difference in robustness of a maternal experience reflects a parity difference in the reinforcing value of pups and factors affecting pup reinforcement. Postpartum and virgin animals were exposed for 15, 30, or 60 min to a novel environment (either a horizontally or vertically striped box) in the presence or absence of pups (or food stimuli) over a 2-, 4-, or 8-day period and then tested for their box preference in a two-choice conditioned place preference paradigm. Postpartum animals preferred the pup-associated box to the alternative box; nulliparous animals did not. The reverse pattern was found when food, rather than pups, was paired with the distinctive environment. However, if nulliparous animals were induced to become maternal either by induction procedures or by hormonal manipulation, they also preferred the pup-associated box. The effect was most robust when animals were stimulated to be maternal by hormones. Finally, pup reinforcement shares properties with other types of reinforcers in being dependent on the functional integrity of the dopamine system. Postpartum animals treated with cis(Z)-flupentixol, a dopamine antagonist, do not develop a conditioned place preference when pups are the reinforcing stimulus. Taken together, these experiments show that pups are potent reinforcers to the maternal animal, regardless of how animals become maternal, but that the hormones of parturition may augment these effects. They show further that pup reinforcement, like food or drug reinforcement, is dopamine dependent.

Is rat-dam licking behavior regulated by pups’ preputial gland secretion?

Anogenital licking (AGL) is crucial for pups’ survival; nonlicked pups cannot defecate, and they die. A cotton swab impregnated with anogenital smears was investigated and the odorous testbox containing it was sniffed by virgins and adult males as well as by dams. When the pups’ heads were rubbed with anogenital smears and the perineal area cleaned, the dams licked only the heads. The same results were obtained with a lipidic extract from pups’ preputial glands. Chromatographic analysis of that extract showed the same peaks as those obtained from anogenital smears and thus confirmed preputial glands as the source of the attractant, Without pups’ preputial glands, AGL did not disappear, but it was disrupted. Some pups were never licked, and died; median licking time increased from 14.5 (control) to 20 sec. Preputial secretions were designated as a regulating factor of AGL. What may induce AGL in the absence of pups’ preputial gland secretion is discussed.

Maternal aggression in response to the risk of infanticide by male mice, Mus domesticus

This study investigated whether maternally aggressive female mice can discriminate between infanticidal and non-infanticidal males. The effect of maternal experience and of the presence or absence of pups on this discrimination were also tested, in a factorial design. Parental experience of the mothers did not influence their responses or those of the males. When pups were present, but not when they were absent, females were more likely to attack infanticidal males than non-infanticidal males. Females were more likely to attack infanticidal males in the presence of pups than in the absence of pups but the reverse occurred with non-infanticidal males. When pups were present, females were more likely to adopt a defensive posture to non-infanticidal males than to infanticidal males. Infanticidal males were more likely to attack the female in the absence of pups than in their presence and this may be because females were less likely to attack them in the former situation. Female attack was initiated by the presence of the male not by his action towards the pups. These data indicate that females discriminate between males of the same reproductive status but of different infanticidal tendencies and respond according to the risk to their young.

Patterns of behaviour during postpartum oestrus in prairie voles, Microtus ochrogaster

Social and sexual behaviour during postpartum oestrus in prairie voles was monitored using time-lapse videotaping over a period of at least 24h. Behaviour was measured as a function of the familiarity and social history of the male partner and as a function of the presence or absence of pups. In general, postpartum oestrus was shorter than male-induced oestrus. When pups remained with the pair, the duration and frequencies of copulatory interactions were further reduced. In familiar pairs mountlordosis bouts were more frequent, and durations of male autogrooming and side-by-side contact were longer than in unfamiliar pairs. All pairs successfully reproduced and litter size among groups was similar, even then the frequency of sexual activities was very low. These results suggest that in monogamous species, such as prairie voles, the social history of the pair was well as female reproductive status are strong determinants of sexual and social interactions that occur during postpartum oestrus.

Offspring control of cerebrospinal fluid GABA concentrations in lactating rats.

The concentrations of gamma-aminobutyric acid (GABA) and its metabolic precursors glutamate (Glu) and ornithine (Orn) were measured in cerebrospinal fluid (CSF) samples obtained from the cisterna magna of freely moving lactating rats on: postpartum day 5 when the rats were with their pups, day 6, 6 h after removal of the pups, and day 7, 24 h after mother-pup reunion. The concentration of GABA was non-detectable in the absence of pups (condition 2) but forty-fold above the limit of detection whenever the rats and the pups were together (conditions 1 and 3). Glu and Orn were low in but increased in and still more so in. Thus, the CSF concentration of GABA, an inhibitory neurotransmitter which profoundly influences behavior and hormone secretion is markedly increased by the pup-related stimuli, which control the behavior and the endocrine secretions of the lactating rat.

Plasma prolactin levels in parental male rats: Effects of increased pup stimuli

The effects of pup exposure on plasma prolactin (PRL) levels were measured in unrestrained, steroid-primed, orchidectomized parental rats. Castrated adult male rats were treated with estradiol and progesterone for 3 weeks and then exposed to rat young until parental behavior was induced. Blood samples were then collected from parental males in both the presence and the absence of pups. Samples were obtained through the use of indwelling cannulas connected via polyethylene tubing to syringes located outside each subject's cage. Despite the intense pup stimulation provided by exposure to nine rat pups, acute rises in plasma PRL levels were not observed in these unrestrained parental male rats. Parental male rats, therefore, do not appear to have the capacity to secrete prolactin in response to acute exposure to young.