Survival and Conflict Behavior of American Black Bears after Rehabilitation

Wildlife agencies face difficult situations when orphaned or injured American black bear (Ursus americanus) cubs (<12 months old) or yearlings (≥12 and <24 months old) are captured. One option is bear rehabilitation, the care and feeding of cubs or yearlings in a semi-natural environment, followed by release. Unfortunately, the survival and movements of bears released from rehabilitation facilities are often poorly documented and the ultimate reasons for success or failure poorly understood. Our goal was to assess survival and post-release conflict of orphaned bear cubs and yearlings following release from a rehabilitation facility, Appalachian Bear Rescue (ABR), in Townsend, Tennessee, USA, from 2015–2016. We predicted that rehabilitated bears would survive at similar rates, die from similar causes, and engage in similar conflict behavior to wild conspecifics. We equipped 42 black bear cubs and yearlings from ABR with global positioning system-collars and released them in Great Smoky Mountains National Park or Cherokee National Forest, Tennessee and North Carolina, USA. Estimated annual survival using known-fate methods for all released bears was 0.93 ± 0.06 [SE]). Survival for 13 bears released as cubs was 0.64 ± 0.14, whereas none of the bears released as yearlings died within 1 year after release (n = 29). Survival of rehabilitated bears was similar to or higher than published rates for wild conspecifics. Three of 42 bears (7.1%) released from ABR engaged in conflict behavior up to 1 year following release, and those had spent time involved in conflict behavior with their mothers (e.g., approaching humans) prior to being orphaned. Despite not having the typical post-natal experience with their mothers, the bears in our study appeared to behave and survive similarly to their wild conspecifics. Rehabilitation is effective for managing orphaned or injured bears. Best survival occurred for bears released as yearlings; however, managers can maximize cub survival through fall releases when plentiful wild foods are available. © 2019 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.     

Behaviour of brown bears killing wild ungulates in the Cantabrian Mountains,Southwestern Europe

Although brown bears (Ursus arctos) are known to be major predators of ungulates in North America and Northern Europe, there is little documentation regarding bear predation on wild ungulates in Southern Europe. We describe search, detection, killing and prey consumption behaviour by brown bears during seven attacks on <1-month roe deer, red deer and chamois fawns in spring in the Cantabrian Mountains, north-western Spain. As soon as the bears detected a fawn by their smell or their mother's presence, they switched from routine foraging on plants and insects to an intensive search for the fawns, mainly using smell to comb a 0.5–1 ha area for 15–45 min. They killed the fawns either while the latter were resting or after a brief chase. The bears usually took their prey to dense vegetation, consuming it immediately. In four cases, 5-month-old cubs accompanying the female did not participate in the hunt. We also document the apparently non-predatory killing of a 40-kg wild boar by a female bear with cubs surprised by a sudden encounter. They did not eat the boar after the attack.     

Reproductive parameters of the common genet <Emphasis Type="Italic">Genetta genetta</Emphasis> (Linnaeus, 1758) in Southwest Europe

We used information from 148 litters belonging to 119 different wild and captive female common genets (Genetta genetta) in SW Europe over a period of almost 50 years to study certain reproductive parameters. Data were obtained from a combination of sources including carcasses, live captures, telemetry-based studies, captive genets, and reports in the literature. The circannual pattern of breeding was fairly similar in both wild and captive genets, with births occurring in all months except December, albeit with a large peak in spring and a secondary peak in autumn. The sex ratio at birth was near to 1:1, and mean litter size was 2.16 ± 0.76 cubs/litter with a range of 1–5 cubs. Litters of two cubs were the most frequent both in wild and captive settings. In captivity, we have observed the births of replacement litters and double litters; however, we did not find evidence of wild females that having two litters in the same year. We conclude that the possibility of breeding at any time of the year is facilitated by the continuous spermatogenesis of the males and by the ability of females to enter into estrus after losing a litter prematurely and to breed twice in the same year.     

Early life social and ecological determinants of global DNA methylation in wild spotted hyenas

Environmental factors early in life can have lasting influence on the development and phenotypes of animals, but the underlying molecular modifications remain poorly understood. We examined cross‐sectional associations among early life socioecological factors and global DNA methylation in 293 wild spotted hyenas (Crocuta crocuta) in the Masai Mara National Reserve, Kenya, grouped according to three age classes (cub, subadult and adult). Explanatory variables of interest included annual maternal rank based on outcomes of dyadic agonistic interactions, litter size, wild ungulate prey density and anthropogenic disturbance in the year each hyena was born based on counts of illegal livestock in the Reserve. The dependent variable of interest was global DNA methylation, assessed via the LUminometric Methylation Assay, which provides a percentage methylation value calculated at CCGG sites across the genome. Among cubs, we observed approximately 2.75% higher CCGG methylation in offspring born to high‐ than low‐ranking mothers. Among cubs and subadults, higher anthropogenic disturbance corresponded with greater %CCGG methylation. In both cubs and adults, we found an inverse association between prey density measured before a hyena was 3 months old and %CCGG methylation. Our results suggest that maternal rank, anthropogenic disturbance and prey availability early in life are associated with later life global DNA methylation. Future studies are required to understand the extent to which these DNA methylation patterns relate to adult phenotypes and fitness outcomes.     

Hand‐rearing and rehabilitation of orphaned wild giant otters,Pteronura brasiliensis,on the Rupununi river,Guyana, South America

From 1985–2003, 34 orphaned giant otters, Pteronura brasiliensis, (22 males, 12 females) were hand raised for eventual return to the wild at The Karanambu Cattle Company Limited Ranch (Karanambu), on the Rupununi River, Guyana, South America. The orphans ranged in age from 2 weeks to 9 months old; most were 8–10‐week‐old cubs. Feeding, housing, exercising, veterinary care, and rehabilitation protocols for young giant otters were developed during this period. Six cubs died during hand‐rearing; of these, four died from illness or injury, and two were killed, one by a caiman and one by another orphaned otter. Of 34 giant otters brought to Karanambu, 28 (82%) were reared successfully to an age and condition suitable for rehabilitation, and 18 (53%) returned to the wild. Ten otters survived hand‐rearing but died either before or during the process of rehabilitation. These hand‐reared giant otters were killed by people (3 known, 2 presumed) or other giant otters (5), including one male otter that remained at Karanambu for several years. During rehabilitation, young giant otters chose to spend increasing amounts of time on the Rupununi River away from human care, often interacting with wild giant otters. Although long‐term monitoring was not possible, Karanambu staff observed most (15 of 18) of the rehabilitated otters repeatedly, for as long as 4 years after their return to the river. The giant otter rehabilitation program at Karanambu generated new knowledge about this species, and offered visitors the opportunity to observe them. Zoo Biol 24:153–167, 2005. © 2005 Wiley‐Liss, Inc.     

RECENT BIOACOUSTIC PUBLICATIONS (2002 and earlier)

The vocal repertoire of the Asiatic Black Bear (Ursus thibetanus) has been poorly studied and until recently only two call types (chuffing and humming) have been described. Here I investigate the vocalizations of three wild orphaned cubs (two males and one female) reared by two observers in natural conditions in the Russian Far East. I grouped the calls into structural types, and then compared them with existing literature data on vocalizations of the same, as well as other species of the Ursidae family. In total, 1302 calls were classified visually from spectrograms into seven call types: whine, moan, yelp, grunt, snort, chuffing and humming. Classification results were verified with discriminant function analysis and randomization. I also fixed the presence of nonlinear phenomena (NLP) and articulation effects in calls. Whine was the most frequently recorded, as well as the most structurally variable call type due to a high rate of NLP. These results indicate that the vocal repertoire of the Asiatic Black Bear cubs is graded, but includes at least two discrete sound types. This work needs to be continued with further studies of vocalizations of cubs and adults of this species to verify the results of this preliminary study.     

25‐OH‐D3, calcium,phosphorus, and alkaline phosphatase content in sera from captive polar bear (Ursus maritimus) cubs at the Denver Zoological Foundation

After the development of rickets in two hand‐reared polar bear (Ursus maritimus) cubs at the Denver Zoological Foundation we initiated a project opportunistically evaluating sera 25‐OH‐D₃, calcium, phosphorus, and alkaline phosphatase levels in seven mother‐reared polar bear cubs. From one to three serum samples were obtained while the cub was still in the den with no access to natural sunlight and one after the cub exited the den. The sera 25‐OH‐D₃ increased as the cubs grew (108±37 nmol/L [n=7] while in den, 184.6±48.3 nmol/L [n=7] out of the den) but were substantially lower then captive adults (348±215 nmol/L [n=36]) or free‐ranging adults (360±135 nmol/L [n=56]). We found that age was correlated significantly with 25‐OH‐D₃ levels but den status (in or out) was not significant. Sera calcium and phosphorus values were highest in denned cubs (calcium, 2.9±0.4 mmol/L [n=13]; phosphorus, 3.1±0.5 mmol/L [n=13]) and then declined as the cubs matured and left the den (calcium, 2.5±0.1 mmol/L [n=7]; phosphorus, 2.4±0.4 mmol/L [n=7]). The enzyme alkaline phosphatase (presumably the bone isoenzyme) was high in denned growing cubs (831±426 IU/L [n=13]) and then declined gradually as the cubs aged and exited the den (96±83 IU/L [n=7]). Zoo Biol 0:1–7, 2007. © 2007 Wiley‐Liss, Inc.     

A Remotely Operated Motorized Burrow Probe to Investigate Carnivore Neonates

Abstract: We describe a miniaturized infrared camera mounted on a remotely operated platform (burrow probe system) that we developed to investigate spotted hyena (Crocuta crocuta) cubs while still in their natal dens. In conjunction with the burrow probe system, we used a hook system to retrieve carcasses from within burrows. To test the utility of these systems, we compared results obtained using the burrow probe and hook to results obtained from intensive above-ground monitoring alone. With the probe, we documented births and litter sizes at significantly younger ages than with above-ground monitoring. The probe was instrumental in detecting cubs that died prior to emergence from the natal den. Retrieval of carcasses allowed collection of genetic samples and data on sex and cause of death. Thus, the burrow probe and hook systems can provide scientists and managers with empirical data on productivity and neonatal mortality of carnivores in the wild; data essential to accurately monitor and model population trends.     

Food intake and mass gain of hand-reared brown bear cubs

Five orphaned European brown bear cubs (Ursus arctos) from 3 litters were hand-reared from the ages of 1–4 months. Body mass initially ranged from 1.7 to 2.8 kg. Growth rates were monitored with reference to diet. Over a period of 3 years, 6 different feed formulas were used. The first 4 formulas were given with bottles until an average age of 133 days. Conversion to mass in the first 10 months ranged from 3.5 to 32.0 g of food per gram of body mass (or 38.1–192.6 kJ of gross energy/gram body mass), and was affected by type of diet. High fat content increased, whereas high carbohydrate content decreased the conversion rates. Formula 3, with 12.0% protein, 23.9% fat, and only 0.2% carbohydrates, simulated values found in bears' milk and produced the best growth rates. Formula 6 (bread, fruits, and meat) was used from ages 7 to 35 months, and over this period, the efficiency of gross energy conversion decreased gradually, by an eventual factor of 3.8. Hand-reared cubs ranged from 1.3 to 2.7 times heavier than 17 wild cubs measured at matching ages. Wild mass is probably limited by maternal hibernation, and by the largely herbivorous nature of the diet. © 1993 Wiley-Liss, Inc.     

Role-Reversed Nepotism Among Cubs and Sires in the Spotted Hyena (Crocuta crocuta)

Nepotism is widespread among parents and offspring, and is typically associated with fundamental asymmetries; parents can usually do more to help their offspring than vice versa, and the cost of a given nepotistic behavior is usually less for parents than for offspring. This may not be so among spotted hyenas (Crocuta crocuta); sires never achieve social rank equal to that of their cubs, to whom they provide no obvious paternal care. Nepotism by sires towards their cubs is thus socially constrained. However, the higher social status of cubs might offset cubs’ developmental disadvantages and permit nepotistic treatment of sires by offspring. We therefore sought to determine whether the interactions among spotted hyena cubs and adult males were influenced by kinship, using long‐term observations from one clan of spotted hyenas. Sires exhibited no overt nepotism towards their cubs in most behaviors, but they did associate more closely with their daughters than with unrelated control females. Sires also associated more closely with their daughters than with their sons, with whom they associated no more closely than they did with unrelated control males. Cubs favored their sires by directing less intense aggression towards them than towards unrelated control males. Cubs of both sexes also associated more closely with their sires than with control males after the cubs were independent of the clan's communal den. Although sires evidently recognize their offspring, paternal nepotism by sires towards their cubs is weaker than filial nepotism by cubs towards their sires. The small size and immaturity of cubs thus appear to be weaker constraints on nepotism than is the low social status of their sires.     

Selection of maternity dens by female polar bears in western Hudson Bay,Canada and the effects of human disturbance

We deployed 19 satellite radio collars on adult female polar bears (Ursus maritimus) in western Hudson Bay to study how pregnant females select maternity-den sites and the degree to which human disturbance might influence this process. To eliminate the possibility that being handled while pregnant might influence the final choice of a suitable site, the collars were attached 1 year before the females were expected to select dens. Our results indicated that pregnant females moved inland and selected an area to den shortly after coming ashore in the summer and remained there if not disturbed. We analyzed 24 years of consecutive data (1979–2002) to examine whether disturbance of pregnant females in the denning area in the autumn affected litter size or mass of cubs the following spring. We defined three levels of disturbance (none—bear not seen; low—bear seen but not handled; high—bear seen and handled), and found that disturbance had no effect on either litter size or the mass of male cubs. However, we did find that females handled in the autumn had significantly lighter female cubs than females that were not seen. Our disturbance of pregnant females occurred in August and September, which is only a few months prior to parturition; it is not known what the effects of disturbance might be in late October or early November, closer to the time when cubs are born.     

Influence of prenatal stress on steroidogenesis in gonads of blue foxes

Handling is a source of stress for farm bred blue foxes. The influence of handling during the late gestational period was investigated in 10-day-old male and female blue foxes. Testosterone and estradiol were measured by RIA in the plasma, gonadal homogenates andin vitro incubates, from blue foxes of both sexes. The gonads were incubatedin vitro without or with human chorionic gonadotropin. In cubs of both sexes, the gonad weights and ovarian estradiol production were decreased by stress. The testicular testosterone and ovarian estradiol contents were increased in prenatally stressed cubs as compared to the controls. The testicular content and baselinein vitro production of testosterone were not affected by prenatal stress, but the testicular response to human chorionic gonadotropin was higher in the stressed group. This study suggests that prenatal stress induced by handling pregnant vixens may influence gonadal steroidogenesis and that this effect was more pronounced in female cubs.     

Growth and teat ownership in a litter of binturongs

Teat ownership has been hypothesized to reduce competition among littermates and has been documented in several species. This study was conducted at the Conservation and Research Center to determine if competition and ownership occurred in the binturong (Arctictis binturong). One litter of four cubs was observed for 2 h, three times per day for 16 wk. Cubs showed definite teat preferences, but no exclusive ownership. Competition, as measured by teat fighting, occurred most frequently for the inguinal pair of mammae. The cubs that suckled most frequently on the inguinal teats had a faster growth rate after day 45. Thus, based on suckle frequency, fight frequency, and growth rates, binturong cubs prefer the inguinal pair of teats.     

Effect of Prenatal Stress on the Pituitary–Adrenal Axis in Blue Foxes

Handling is a source of stress for farm bred blue foxes. The influence of handling during the late gestation period on the pituitary–adrenal axis was studied in 10-day old male and female blue foxes. Cortisol and progesterone were measured by radioimmunoassay in the plasma, adrenal homogenates, and in vitro incubates from animals of both sexes. Adrenals were incubated in vitro in the absence or presence of ACTH. In addition, the adrenal weight and plasma concentration of ACTH were assessed. In cubs of both sexes, the adrenal weight was decreased after prenatal stress treatment. The plasma concentration of progesterone and the adrenal cortisol in vitro production were elevated in the prenatally stressed female cubs, as compared to the control, along with the adrenal progesterone in vitro production in prenatally stressed male cubs. The adrenal cortisol and progesterone content and plasma ACTH and cortisol concentrations were not affected by prenatal stress. In conclusion, the results of this study suggest that the prenatal stress induced by handling pregnant vixens can affect the pituitary–adrenal axis in neonatal offspring, this effect being more pronounced in female cubs.     

Reproductive Ecology of American Black Bears in the Alleghany Mountains of Virginia,USA

We studied reproduction of American black bears (Ursus americanus) in western Virginia from 1994 to 2003. We handled 326 ≥2-year-old female black bears 672 times during summer trapping and followed 176 of these individuals through 424 winter den seasons. We examined 183 litters consisting of 455 cubs. Primiparity occurred at mean and modal ages of 3.8 and 3 years, respectively. Composite mean litter size was 2.49 (SE = 0.06) cubs/litter; 3- and 4-year-olds had smaller litters than older bears. We tracked reproductive synchrony using 5 indices and documented a resetting of this synchrony, likely in response to hard-mast failure. The amplitude of oscillations in synchrony indices dampened through time after the synchronizing events. Documentation and quantification of relationships between nutrient availability, reproduction and population dynamics can be used to inform population modeling efforts and more accurately forecast harvest. © 2011 The Wildlife Society.     

Natural and anthropogenic drivers of cub recruitment in a large carnivore

Recruitment is a critical parameter governing population dynamics and influences population persistence. Understanding the drivers of recruitment is therefore important for conservation, especially for long‐lived mammals such as large carnivores, which have low reproductive rates, rendering them prone to extinction. Using cheetahs (Acinonyx jubatus) as a model species, I investigated the variation in cub recruitment in relation to habitat and the abundance of tourists and predators. Per litter, female cheetahs on average raised 1.71 ± 1.35 cubs to independence, but this varied depending on the presence of open habitat and the abundance of tourists, both of which had a negative effect on cub recruitment. More specifically, female cheetahs that were mostly found in open habitats on average raised 1.69 ± 0.14 cubs per litter to independence compared to 3.04 ± 0.26 cubs in denser habitat. Similarly, female cheetahs that were exposed to high tourist abundance on average raised 0.21 ± 0.72 cubs to independence compared to 2.32 ± 0.11 cubs in low tourism areas. Neither lion nor spotted hyaena abundance had an impact on the number of cubs that were recruited. Based on these findings, I recommend that the importance of a heterogeneous environment should be taken into consideration in habitat management, restoration efforts, and reintroduction programs. In addition, tourist quotas should be put in place in high visitation areas and strict wildlife viewing guidelines, such as number of vehicles, tourist behavior, time spent, and distance to a sighting, should be enforced. Cub recruitment is an important component of species persistence and incorporating these findings could aid conservation efforts for species that are increasingly under threat.     

Consistent individual behavior: evidence of personality in black bears

Personality is defined as consistency in individual differences in organismal behavior across time or context, a phenomenon of interest within behavioral and evolutionary ecology. Empirical data have revealed an ever-increasing number and diversity of taxa that display these phenotypic patterns in both wild and captive settings. Moreover, these behavioral traits are frequently linked to wild behavior, life history strategies, and measures of individual fitness. Understanding personality is of particular importance for some animals, such as large carnivores, which may express maladaptive behavior that can lead to conflict with humans. To date, few studies of personality exist on large carnivores and none have investigated the presence of personality in black bears (Ursus americanus). Through focal animal sampling, and open field, novel object, and startle object tests, we investigate the potential for personality in captive black bear cubs. Results indicate the presence of personality, with consistency in behavior across five metrics for the bold-shy axis, and eight sampling events measuring responses for the activity axis. Information presented here reveals the presence of personality in black bear cubs, and may provide a framework for future investigations into relationships of personality with ecology and life history.     

Reproductive life history of South African cheetahs (Acynonyx jubatus jubatus) at the San Diego Zoo Wild Animal Park, 1970–2005

We analyzed 35 years of data from a captive breeding program of cheetahs to determine basic reproductive life history characteristics of females. Breeding females ranged in age from 2.7–10.5 years. Sixteen females and over 13 males produced 129 cubs in 36 litters, with an average litter size of 3.6. Older females produced significantly fewer cubs per litter than younger females, but cub survivorship was comparable across female ages. Sex ratio was balanced at birth and 71% of infants survived the weaning period. Given that the reproductive output of captive cheetahs in our study is similar to that in other zoologic institutions and to cheetahs in the wild, we suggest that reproductive deficits in captive cheetahs arise from the inability of some pairs to breed, due to a lack of mating preference, rather than from a species‐wide problem. Zoo Biol 0:1–8, 2006. © 2006 Wiley‐Liss, Inc.     

Population dynamics of pedigree leopards,Panthera pardus ssp,in captivity

The demographic history of 4 races or subspecies of leopard, Panthera pardus, was reviewed from international studbook records dating back to 1953. The Chinese leopard has been the most common pedigree race maintained in captivity, a factor linked to the length of time (29 years) this subspecies has been in captivity. The relative youth of the wild-born founders also helped them to adjust to captivity as well as live long reproductive lives. Today, however, this race is suffering from the ill effects of inbreeding due to the small founder size. This condition appears to be correctable now that additional specimens have been located. Persian leopards have a larger founder size than the former race, but some of their ancestors were older animals at the time of acquisition. Because of this, their potential fecundity was probably depressed from psychological problems related to adjustment and a shorter life span in captivity. Two founding females experienced pelvic deformities while young, and few of their cubs survived because they all had to be delivered via caesarian section. This procedure also shortened the reproductive life of the females involved because the owning zoos refrained from breeding the animals in the leopards' later years. Captive leopards appear to live longer than their wild counterparts, although precise data on wild populations is not available. In captivity many reach 12–15 years old, and exceptional individuals of several races have lived 20 years. Most captive-born leopards begin breeding when they are 3 years old and continue until they are 8–10 years old. Reproduction in females usually ceases at 12–14 years, although males have a longer reproductive life, with several successfully breeding when 19–20 years old.