Wyatt, 2014), a phenomenon termed pheromonal parsimony. For instance, some pheromones elicit resp... more Wyatt, 2014), a phenomenon termed pheromonal parsimony. For instance, some pheromones elicit responses only when emitted at specific concentrations, and the concentration of a signal can change the meaning of the message entirely (e.g., Bordereau & Pasteels, 2011; Foster & Johnson, 2011). Animals should only respond to signals above a certain concentration to minimize associated costs; behavioural response thresholds therefore reflect differences in a
As a means to compare and contrast to free-ranging Florida manatees, we examined the behavior and... more As a means to compare and contrast to free-ranging Florida manatees, we examined the behavior and movement patterns of nine adult-female captive manatees at Homosassa Springs Wildlife State Park (HSWSP). HSWSP has a unique manatee exhibit that consists of a natural river and a man-made pool. Because the manatees are exposed to a natural environment including natural food resources, the study of various aspects of behavioral and physiological parameters of the captive manatees is especially valuable with this group. We determined activity pattern and spatial use of the facility by manatees over three allotted periods of a day (noon, mid-afternoon, and late-afternoon) and three seasons (winter, spring, and summer). Behavioral strategies of the manatees were: 1) to remain ''inactive,'' probably to conserve energy, during the day while the park provisioned food; 2) to alter locations during the course of the afternoon, apparently with the direction of the sun, possibly to assist with thermoregulation; and 3) to change location seasonally where and when food resources became abundant, showing a strong interest in natural vegetation as it became available. Spatial use and activity pattern of the HSWSP captive manatees apparently were influenced by energy constraints and nutrient intake by provisioned food availability over the day and natural vegetation over the study period. The behavior of the female group of manatees may have been affected by the singlesex living arrangement. In addition, these manatees are subject to a largely
Sexual dimorphism in morphology can be accompanied by behavioural differences between the sexes. ... more Sexual dimorphism in morphology can be accompanied by behavioural differences between the sexes. We examined if investigatory behaviour involving the trunk of African elephants showed sexual dimorphism. Males compete and search for females, but they have a lengthy period of development before they are socially viable mates. Receptive females are relatively rare. We hypothesized that males would display higher rates of chemosensory behaviour following puberty than females. Because males disperse, they were hypothesized to be more likely to contact elephants outside their kinship group. We observed the trunk tip, chemosensory behaviours of African elephants at Addo Elephant National Park, South Africa. For 208 elephants, we found no significant differences in state behaviours around waterholes by age or sex. Yet, older elephants were more likely to investigate the environment and elephant excrement than younger animals. Males were more likely to investigate urine and faeces than females. Only post-puberty animals contacted non-family with males investigating both sexes, while investigations by and to females only involved post-puberty males. Overall, the probability of performing chemosensory behaviours depended on age and sex. Male elephants appear more reliant than females on signals in urine and faeces with ensuing inspections of individuals through trunk tip contacts.
African elephants are a polygynous species that raise offspring in a matriarchal society. Unlike ... more African elephants are a polygynous species that raise offspring in a matriarchal society. Unlike females, males disperse, spend time in male groups and search for mates when mature. Urinary chemical signals aid males in detecting reproductively active females. A preovulatory pheromone has been identified in Asian elephants, Elephas maximus, but has not yet been experimentally identified in African elephants. In this study, the goal was to determine whether adult captive male African elephants can distinguish between urine from conspecific females in luteal and periovulatory oestrous stages as an indication that a preovulatory pheromone is released in the urine. Urine was collected from seven different female African elephants during their luteal and periovulatory periods of oestrus. Bioassays were conducted with nine adult male elephants housed at six different facilities. Males were presented with the two urine types and a control sample once a day over 3 days to reduce sample novelty, which can result in misleadingly high responses. All males showed greater chemosensory responses to the periovulatory urine by trial 3 with the ability to distinguish the urines increasing over the 3 days. This is the first experimental behavioural evidence that African elephants release an oestrous pheromone in the urine. The ability of the captive male elephants to discern between the two urine types bolsters the hypothesis that there is a preovulatory pheromone in African elephants and encourages efforts to identify it.
Signal design and meaning are dependent on the condition of the sender and receiver as well as th... more Signal design and meaning are dependent on the condition of the sender and receiver as well as the response of the receiver. This study examined (1) whether female Asian elephants, Elephas maximus, can distinguish between a conspecific male in musth and nonmusth states using urinary signals, (2) how the oestrous condition of the female affects discrimination, and (3) correlation of female responses with the testosterone level of the male. Musth is a rut-like state displayed by healthy adult male elephants. Males in musth dominate nonmusth males and may be preferred by females as mates. Urine was collected from two captive male Asian elephants during nonmusth periods and from one of these males during times of musth. Samples of musth and nonmusth urine and control liquids were placed in an elephant enclosure weekly for 16 weeks, the length of a female oestrous cycle. Primary response behaviours were approach and four trunk-tip motions, namely sniff, check, place and flehmen. Musth urine consistently elicited greater responses than nonmusth and control samples. Females were more responsive during their follicular (sexually receptive) than luteal (unreceptive) stages of oestrus. Furthermore, females appeared to be sensitive to the degree of musth as responses increased with rising serum testosterone levels of the male donor. Chemical signals from males are a likely source of honest signals related to status and reproductive condition. Female elephants appear capable of detecting differences in a male based upon urinary chemosignals.
Enantiomers are stereoisomeric molecules, nonsuperimposable mirror images of each other yet other... more Enantiomers are stereoisomeric molecules, nonsuperimposable mirror images of each other yet otherwise identical. Such small, volatile, chiral compounds are frequently responsible for a diversity of defined chemical messages and corresponding (or resultant) precision of evoked responses most typically seen in insect chemical communication. Male Asian elephants (Elephas maximus) in musth rely on a racemic ratio of one such compound, frontalin, which is secreted from the temporal gland to deliver honest messages to conspecifics. Frontalin is a well-known aggregation pheromone of several species of bark beetles. The precision of behavioral responses evoked by various enantiomeric ratios of frontalin is most evident in conspecific females in their follicular phase of estrus. Varying enantiomeric ratios of beetle pheromones exo- and endo-brevicomin are also demonstrated in temporal gland secretions from male and female Asian elephants. Additionally, interspecific similarities were observed in the biosynthetic precursors of frontalin. The remarkable parallels in the emission and bioactivity of frontalin ratio blends in bark beetles and elephants suggest an intriguing convergence and even conservation in pheromone receptor function and principles.
Journal of Contemporary Water Research & Education, Apr 1, 2016
hard corals [see Angelini et al. 2012]), ecosystem engineers (e.g., in some cases herbivores that... more hard corals [see Angelini et al. 2012]), ecosystem engineers (e.g., in some cases herbivores that modify habitat like beavers or elephants [Jones et al. 1994]), or keystone species (such as terminal or near terminal trophic predators [Fleeger et al. 2003]). For this paper, we focus on the sublethal effects of water-borne pollutants and the roles of an ecosystem engineer, the beaver, and a keystone species, the otter, in freshwater habitats. Our tenet is that the interactions between two such ecosystem forces can potentially have profound impacts on the ecosystem that might not be predicted by considering only one. Ecosystem engineers are those species that "directly or indirectly modulate the availability of resources to other species, by causing physical state changes in biotic or abiotic materials" (Jones et al. 1994, 373). Eurasian and North American beavers (Castor fiber and C. canadensis, respectively) are notable ecosystem engineers because they create wetlands, affecting sediments, organic matter, nutrient cycling, decomposition, water flow and temperature,
At many beaver (Castor canadensis) sites at Allegany State Park in New York State, red maple (Ace... more At many beaver (Castor canadensis) sites at Allegany State Park in New York State, red maple (Acer rubrum) is the only or one of the few tree species left standing at the ponds' edges. The relative palatability of red maple (RM) was studied in three ways. (1) At seven beaver sites, the available and utilized trees were recorded and an electivity index (E) computed. Of 15 tree species, RM ranked second or fourth lowest. (2) In experiment I, RM, sugar maple (A. saccharum, SM), and quaking aspen (Populus tremuloides) logs were presented cafeteria style at 10 colonies. RM was the least preferred. (3) Bark of RM was extracted with solvents. Aspen logs were painted (experiment II) or soaked (experiment III) with this RM extract and presented to beaver cafeteria-style, along with aspen and RM controls. This treatment rendered aspen logs less palatable, indicating that a chemical factor had been transferred.
North American beavers are considered ecosystem engineers. Their activities can quickly and drast... more North American beavers are considered ecosystem engineers. Their activities can quickly and drastically alter habitat properties and perhaps permit highly aggressive colonizing plants, notably non-native species, to invade and potentially dominate. This study examined if beavers in southeastern Georgia have an effect on the terrestrial plant community. Sampling areas included beaver modified (N=9) and nearby but relatively non-impacted riparian habitat (N=9) in a matched pairs design. Vegetation surveys were performed in spring and summer. Species richness was calculated for herbs, vines, woody seedlings, and woody vegetation. Richness of herbaceous vegetation was higher at distances closer to shore while richness of large woody vegetation increased with distance from shore. Woody vegetation also was more abundant in beaver sites. Composition was not different between the two site types. The presence of exotic species was rare and did not differ by site type. This study provides evidence that beavers may play an important role in determining the vegetative structure of their community.
Females of species that live in matrilineal hierarchies may compete for temporally limited resour... more Females of species that live in matrilineal hierarchies may compete for temporally limited resources, yet maintain social harmony to facilitate cohesion. The relative degree of aggressive and nonaggressive interactions may depend on the reproductive condition of sender and receiver. Individuals can benefit by clearly signaling and detecting reproductive condition. Asian elephants (Elephas maximus) live in social matrilineal herds. Females have long estrous cycles (14-16 weeks) composed of luteal (8-12 weeks) and follicular (4-8 weeks) phases. In this study, we observed the behavior of four captive Asian elephant females during multiple estrous cycles over 2 years. We evaluated whether investigative, aggressive, and tail flicking behaviors were related to reproductive condition. Investigative trunk tip contacts showed no distinct pattern by senders, but were more prevalent toward female elephants that were in their follicular compared with their luteal phase. The genital area was the most frequently contacted region and may release reproductively related chemosignals. Aggression did not differ significantly with estrus; however, rates of aggression were elevated when senders were approaching ovulation and receivers were in the luteal phase.
Musth is an annual, yet asynchronous, rut-like condition that is experienced by many adult Africa... more Musth is an annual, yet asynchronous, rut-like condition that is experienced by many adult African and Asian male elephants. Behaviorally, musth is characterized by heightened aggression, decreased feeding, urine dribbling, temporal gland secretion and enhanced sexual activity. Musth improves the access of a male to reproductively active females through increased mobility and a higher dominance ranking (intrasexual competition). Whether females prefer males in musth as mates is as yet uncertain (intersexual choice). Females can distinguish among the odors of males in musth and nonmusth. Although behavioral musth has been associated with greatly elevated plasma testosterone levels, a recent study in Sri Lanka shows that intensified aggressiveness follows maximal testosterone secretion and proposes that behavioral musth is a consequence of declining androgen levels. Our data from an Asian male elephant in North America suggest that either declining or rising serum testosterone may be related to "musth behaviors." Our report demonstrates that certain aspects of body physiology are greatly altered during musth. Rather than a single state, our data suggest that musth is an ever-changing condition with some typical stages. Specific chemical compounds released at different stages of musth may serve individually or in combination as honest signals of male condition.
Selective pressures on individual behavior serve to mold social structure and subsequent levels o... more Selective pressures on individual behavior serve to mold social structure and subsequent levels of cooperation in social species, including elephants. Adult Asian (Elephas maximus) and African (Loxodonta africana) elephants have complex social societies that differ markedly between the sexes. Elephant social structure and cooperative behavior may have evolved in part to prepare young elephants to meet the challenges of an expansive environment, predators and parasites. In captivity, such forces are relaxed or eliminated, yet captive elephants display a similar repertoire of behaviors as their wild counterparts. Elephants live in herds of related adult females from several generations. This female social unit is centered on calves and the matriarch. Adult males reside in bachelor herds, singly, or frequent female groups, depending on male age and reproductive condition. In captivity, female elephants are usually housed together, although group size is smaller than in the wild, whereas adult males are generally housed separately from other elephants. Beyond these general similarities between wild and captive settings, captive elephants are housed in a wider range of group sizes, degrees of relatedness, and age structures than would be typical in the wild. This variation in social structure can be used to explore questions about cooperative behavior. Following a comparison of wild and captive social structures for elephants, three such potential avenues for study are discussed. Specifically, research with captive elephants could shed light on the development of social behavior, the functional significance of allomothering, and the ability of elephants to recognize kin or social group members. Beside the potential theoretical implications and insight into wild elephant behavior, the examination of social behavior also has important ramifications for the management of animals in captivity.
African elephants Loxodonta africana and Asian elephants Elephas maximus are not thriving in many... more African elephants Loxodonta africana and Asian elephants Elephas maximus are not thriving in many captive settings and are threatened throughout their native ranges. Many zoos support in situ conservation projects and provide opportunities to conduct ex situ research in controlled settings with comparably approachable animals. Zoo elephant projects may facilitate fieldwork with free-ranging elephants (e.g. development of non-invasive sampling and analytical tools), which may then also improve the husbandry of elephants in human care. Free-ranging elephants also benefit from drug therapies and veterinary care when they are orphaned, kept as working elephants or brought in as rehabilitation casesespecially as human-elephant conflicts become more common as a result of ever-expanding human populations. Much has been learned about the basic biology and husbandry needs of elephants but, often, the more we learn, the more questions arise. There are physiological differences between African and Asian elephants, and this should affect the management of these animals. This paper will provide brief overviews of the current state of knowledge regarding the pharmacology, nutrition, reproduction, sensory biology and diseases (primarily elephant endotheliotropic herpesvirus infections) relevant to elephants with recommendations for future research.
Free-ranging African elephants are highly social animals that live in a society where age, size, ... more Free-ranging African elephants are highly social animals that live in a society where age, size, kinship, and disposition all contribute to social rank. Although captive elephant herds are small and largely comprises of unrelated females, dominance hierarchies are common. The goal of this study was to delineate how the behavior of captive female African elephants varies with respect to age and social rank based on a combination of keeper questionnaires and behavioral observations. ''Body movements'' and ''trunk to'' behaviors of 33 nonpregnant female African elephants housed at 14 North American zoos were recorded over 8 hr. Keepers at each facility also rated each elephant based on a series of questions about interactions with herdmates. The assessment of social rank based on observations correlated strongly with ranks assigned by keepers via the questionnaires. Observations and questionnaire responses indicated that body weight of the female, and to a lesser extent age, were significantly related to rates and types of ''body movements'' and that these demographic factors dictate the captive elephant hierarchy, similar to that observed in the wild. Many of the observed ''body movements,'' such as back away, displace, push, and present,
Abstract: Controlling beaver (Castor canadensis) populations is a problematic issue for wildlife ... more Abstract: Controlling beaver (Castor canadensis) populations is a problematic issue for wildlife managers in North America. Management of beaver can be facilitated by determining sex ratio of a population, but this requires ready identification of gender for live and harvested ...
Human–wildlife conflict (HWC) is a pervasive, global conservation issue that occurs whenever inte... more Human–wildlife conflict (HWC) is a pervasive, global conservation issue that occurs whenever interactions between people and wildlife result in a negative outcome for either or both parties or the resources upon which they rely. Humans are impacted by wildlife either directly through their survival or health, or indirectly through damage to their food resources or property. Alleviating HWC has relied upon means from the individual to the population scale. Problem animals can be killed, relocated, or trained to avoid human habitations. Animal populations can be reduced through lethal or non-lethal means. Lethal control or relocation often have consequences such as biodiversity loss, unforeseen trophic cascades, and other ecologically detrimental effects. In many cases, the preference may be to keep the animals in question in the region but to reduce their impact on humans. In such situations, barriers can be constructed but these also have potential negative ramifications for other species as well as high costs for construction and maintenance. For invertebrate pests, a push–pull integrated pest management strategy has become increasingly popular. Chemical signals in the form of a natural repellents and attractants serve to keep pests away from crops and attract them to other areas, often traps. For vertebrates, the lack of known chemical signals hampers this approach and furthermore, the lethal trapping of individuals often is undesired. However, biological fences in concert with training animals to avoid the conflict area (e.g., crop or livestock) have potential for reducing HCW, especially for longer-lived, medium- to large-sized vertebrates. In lieu of using natural signals with known function, the proposition is to invoke a novel odor that would be unusual in the range of the problem species. Such an odor would be associated with strongly aversive stimuli near points of conflict and used as a warning of such a stimulus for future encounters. This novel scent fence would elicit anxiety and arouse a memory of discomfort and fear in the animal, motivating it to move away from the area without another interaction with the aversive stimulus. The odor would create an atmosphere of unease and avoidance rather than be the repellent itself. This approach provides further impetus for understanding better the chemical communication and the specific chemical signals used by vertebrates. In advance of those discoveries, odors may be useful as part of an aversive conditioning program to alter movement patterns of animals and keep them away from crops and livestock.
Wyatt, 2014), a phenomenon termed pheromonal parsimony. For instance, some pheromones elicit resp... more Wyatt, 2014), a phenomenon termed pheromonal parsimony. For instance, some pheromones elicit responses only when emitted at specific concentrations, and the concentration of a signal can change the meaning of the message entirely (e.g., Bordereau & Pasteels, 2011; Foster & Johnson, 2011). Animals should only respond to signals above a certain concentration to minimize associated costs; behavioural response thresholds therefore reflect differences in a
As a means to compare and contrast to free-ranging Florida manatees, we examined the behavior and... more As a means to compare and contrast to free-ranging Florida manatees, we examined the behavior and movement patterns of nine adult-female captive manatees at Homosassa Springs Wildlife State Park (HSWSP). HSWSP has a unique manatee exhibit that consists of a natural river and a man-made pool. Because the manatees are exposed to a natural environment including natural food resources, the study of various aspects of behavioral and physiological parameters of the captive manatees is especially valuable with this group. We determined activity pattern and spatial use of the facility by manatees over three allotted periods of a day (noon, mid-afternoon, and late-afternoon) and three seasons (winter, spring, and summer). Behavioral strategies of the manatees were: 1) to remain ''inactive,'' probably to conserve energy, during the day while the park provisioned food; 2) to alter locations during the course of the afternoon, apparently with the direction of the sun, possibly to assist with thermoregulation; and 3) to change location seasonally where and when food resources became abundant, showing a strong interest in natural vegetation as it became available. Spatial use and activity pattern of the HSWSP captive manatees apparently were influenced by energy constraints and nutrient intake by provisioned food availability over the day and natural vegetation over the study period. The behavior of the female group of manatees may have been affected by the singlesex living arrangement. In addition, these manatees are subject to a largely
Sexual dimorphism in morphology can be accompanied by behavioural differences between the sexes. ... more Sexual dimorphism in morphology can be accompanied by behavioural differences between the sexes. We examined if investigatory behaviour involving the trunk of African elephants showed sexual dimorphism. Males compete and search for females, but they have a lengthy period of development before they are socially viable mates. Receptive females are relatively rare. We hypothesized that males would display higher rates of chemosensory behaviour following puberty than females. Because males disperse, they were hypothesized to be more likely to contact elephants outside their kinship group. We observed the trunk tip, chemosensory behaviours of African elephants at Addo Elephant National Park, South Africa. For 208 elephants, we found no significant differences in state behaviours around waterholes by age or sex. Yet, older elephants were more likely to investigate the environment and elephant excrement than younger animals. Males were more likely to investigate urine and faeces than females. Only post-puberty animals contacted non-family with males investigating both sexes, while investigations by and to females only involved post-puberty males. Overall, the probability of performing chemosensory behaviours depended on age and sex. Male elephants appear more reliant than females on signals in urine and faeces with ensuing inspections of individuals through trunk tip contacts.
African elephants are a polygynous species that raise offspring in a matriarchal society. Unlike ... more African elephants are a polygynous species that raise offspring in a matriarchal society. Unlike females, males disperse, spend time in male groups and search for mates when mature. Urinary chemical signals aid males in detecting reproductively active females. A preovulatory pheromone has been identified in Asian elephants, Elephas maximus, but has not yet been experimentally identified in African elephants. In this study, the goal was to determine whether adult captive male African elephants can distinguish between urine from conspecific females in luteal and periovulatory oestrous stages as an indication that a preovulatory pheromone is released in the urine. Urine was collected from seven different female African elephants during their luteal and periovulatory periods of oestrus. Bioassays were conducted with nine adult male elephants housed at six different facilities. Males were presented with the two urine types and a control sample once a day over 3 days to reduce sample novelty, which can result in misleadingly high responses. All males showed greater chemosensory responses to the periovulatory urine by trial 3 with the ability to distinguish the urines increasing over the 3 days. This is the first experimental behavioural evidence that African elephants release an oestrous pheromone in the urine. The ability of the captive male elephants to discern between the two urine types bolsters the hypothesis that there is a preovulatory pheromone in African elephants and encourages efforts to identify it.
Signal design and meaning are dependent on the condition of the sender and receiver as well as th... more Signal design and meaning are dependent on the condition of the sender and receiver as well as the response of the receiver. This study examined (1) whether female Asian elephants, Elephas maximus, can distinguish between a conspecific male in musth and nonmusth states using urinary signals, (2) how the oestrous condition of the female affects discrimination, and (3) correlation of female responses with the testosterone level of the male. Musth is a rut-like state displayed by healthy adult male elephants. Males in musth dominate nonmusth males and may be preferred by females as mates. Urine was collected from two captive male Asian elephants during nonmusth periods and from one of these males during times of musth. Samples of musth and nonmusth urine and control liquids were placed in an elephant enclosure weekly for 16 weeks, the length of a female oestrous cycle. Primary response behaviours were approach and four trunk-tip motions, namely sniff, check, place and flehmen. Musth urine consistently elicited greater responses than nonmusth and control samples. Females were more responsive during their follicular (sexually receptive) than luteal (unreceptive) stages of oestrus. Furthermore, females appeared to be sensitive to the degree of musth as responses increased with rising serum testosterone levels of the male donor. Chemical signals from males are a likely source of honest signals related to status and reproductive condition. Female elephants appear capable of detecting differences in a male based upon urinary chemosignals.
Enantiomers are stereoisomeric molecules, nonsuperimposable mirror images of each other yet other... more Enantiomers are stereoisomeric molecules, nonsuperimposable mirror images of each other yet otherwise identical. Such small, volatile, chiral compounds are frequently responsible for a diversity of defined chemical messages and corresponding (or resultant) precision of evoked responses most typically seen in insect chemical communication. Male Asian elephants (Elephas maximus) in musth rely on a racemic ratio of one such compound, frontalin, which is secreted from the temporal gland to deliver honest messages to conspecifics. Frontalin is a well-known aggregation pheromone of several species of bark beetles. The precision of behavioral responses evoked by various enantiomeric ratios of frontalin is most evident in conspecific females in their follicular phase of estrus. Varying enantiomeric ratios of beetle pheromones exo- and endo-brevicomin are also demonstrated in temporal gland secretions from male and female Asian elephants. Additionally, interspecific similarities were observed in the biosynthetic precursors of frontalin. The remarkable parallels in the emission and bioactivity of frontalin ratio blends in bark beetles and elephants suggest an intriguing convergence and even conservation in pheromone receptor function and principles.
Journal of Contemporary Water Research & Education, Apr 1, 2016
hard corals [see Angelini et al. 2012]), ecosystem engineers (e.g., in some cases herbivores that... more hard corals [see Angelini et al. 2012]), ecosystem engineers (e.g., in some cases herbivores that modify habitat like beavers or elephants [Jones et al. 1994]), or keystone species (such as terminal or near terminal trophic predators [Fleeger et al. 2003]). For this paper, we focus on the sublethal effects of water-borne pollutants and the roles of an ecosystem engineer, the beaver, and a keystone species, the otter, in freshwater habitats. Our tenet is that the interactions between two such ecosystem forces can potentially have profound impacts on the ecosystem that might not be predicted by considering only one. Ecosystem engineers are those species that "directly or indirectly modulate the availability of resources to other species, by causing physical state changes in biotic or abiotic materials" (Jones et al. 1994, 373). Eurasian and North American beavers (Castor fiber and C. canadensis, respectively) are notable ecosystem engineers because they create wetlands, affecting sediments, organic matter, nutrient cycling, decomposition, water flow and temperature,
At many beaver (Castor canadensis) sites at Allegany State Park in New York State, red maple (Ace... more At many beaver (Castor canadensis) sites at Allegany State Park in New York State, red maple (Acer rubrum) is the only or one of the few tree species left standing at the ponds' edges. The relative palatability of red maple (RM) was studied in three ways. (1) At seven beaver sites, the available and utilized trees were recorded and an electivity index (E) computed. Of 15 tree species, RM ranked second or fourth lowest. (2) In experiment I, RM, sugar maple (A. saccharum, SM), and quaking aspen (Populus tremuloides) logs were presented cafeteria style at 10 colonies. RM was the least preferred. (3) Bark of RM was extracted with solvents. Aspen logs were painted (experiment II) or soaked (experiment III) with this RM extract and presented to beaver cafeteria-style, along with aspen and RM controls. This treatment rendered aspen logs less palatable, indicating that a chemical factor had been transferred.
North American beavers are considered ecosystem engineers. Their activities can quickly and drast... more North American beavers are considered ecosystem engineers. Their activities can quickly and drastically alter habitat properties and perhaps permit highly aggressive colonizing plants, notably non-native species, to invade and potentially dominate. This study examined if beavers in southeastern Georgia have an effect on the terrestrial plant community. Sampling areas included beaver modified (N=9) and nearby but relatively non-impacted riparian habitat (N=9) in a matched pairs design. Vegetation surveys were performed in spring and summer. Species richness was calculated for herbs, vines, woody seedlings, and woody vegetation. Richness of herbaceous vegetation was higher at distances closer to shore while richness of large woody vegetation increased with distance from shore. Woody vegetation also was more abundant in beaver sites. Composition was not different between the two site types. The presence of exotic species was rare and did not differ by site type. This study provides evidence that beavers may play an important role in determining the vegetative structure of their community.
Females of species that live in matrilineal hierarchies may compete for temporally limited resour... more Females of species that live in matrilineal hierarchies may compete for temporally limited resources, yet maintain social harmony to facilitate cohesion. The relative degree of aggressive and nonaggressive interactions may depend on the reproductive condition of sender and receiver. Individuals can benefit by clearly signaling and detecting reproductive condition. Asian elephants (Elephas maximus) live in social matrilineal herds. Females have long estrous cycles (14-16 weeks) composed of luteal (8-12 weeks) and follicular (4-8 weeks) phases. In this study, we observed the behavior of four captive Asian elephant females during multiple estrous cycles over 2 years. We evaluated whether investigative, aggressive, and tail flicking behaviors were related to reproductive condition. Investigative trunk tip contacts showed no distinct pattern by senders, but were more prevalent toward female elephants that were in their follicular compared with their luteal phase. The genital area was the most frequently contacted region and may release reproductively related chemosignals. Aggression did not differ significantly with estrus; however, rates of aggression were elevated when senders were approaching ovulation and receivers were in the luteal phase.
Musth is an annual, yet asynchronous, rut-like condition that is experienced by many adult Africa... more Musth is an annual, yet asynchronous, rut-like condition that is experienced by many adult African and Asian male elephants. Behaviorally, musth is characterized by heightened aggression, decreased feeding, urine dribbling, temporal gland secretion and enhanced sexual activity. Musth improves the access of a male to reproductively active females through increased mobility and a higher dominance ranking (intrasexual competition). Whether females prefer males in musth as mates is as yet uncertain (intersexual choice). Females can distinguish among the odors of males in musth and nonmusth. Although behavioral musth has been associated with greatly elevated plasma testosterone levels, a recent study in Sri Lanka shows that intensified aggressiveness follows maximal testosterone secretion and proposes that behavioral musth is a consequence of declining androgen levels. Our data from an Asian male elephant in North America suggest that either declining or rising serum testosterone may be related to "musth behaviors." Our report demonstrates that certain aspects of body physiology are greatly altered during musth. Rather than a single state, our data suggest that musth is an ever-changing condition with some typical stages. Specific chemical compounds released at different stages of musth may serve individually or in combination as honest signals of male condition.
Selective pressures on individual behavior serve to mold social structure and subsequent levels o... more Selective pressures on individual behavior serve to mold social structure and subsequent levels of cooperation in social species, including elephants. Adult Asian (Elephas maximus) and African (Loxodonta africana) elephants have complex social societies that differ markedly between the sexes. Elephant social structure and cooperative behavior may have evolved in part to prepare young elephants to meet the challenges of an expansive environment, predators and parasites. In captivity, such forces are relaxed or eliminated, yet captive elephants display a similar repertoire of behaviors as their wild counterparts. Elephants live in herds of related adult females from several generations. This female social unit is centered on calves and the matriarch. Adult males reside in bachelor herds, singly, or frequent female groups, depending on male age and reproductive condition. In captivity, female elephants are usually housed together, although group size is smaller than in the wild, whereas adult males are generally housed separately from other elephants. Beyond these general similarities between wild and captive settings, captive elephants are housed in a wider range of group sizes, degrees of relatedness, and age structures than would be typical in the wild. This variation in social structure can be used to explore questions about cooperative behavior. Following a comparison of wild and captive social structures for elephants, three such potential avenues for study are discussed. Specifically, research with captive elephants could shed light on the development of social behavior, the functional significance of allomothering, and the ability of elephants to recognize kin or social group members. Beside the potential theoretical implications and insight into wild elephant behavior, the examination of social behavior also has important ramifications for the management of animals in captivity.
African elephants Loxodonta africana and Asian elephants Elephas maximus are not thriving in many... more African elephants Loxodonta africana and Asian elephants Elephas maximus are not thriving in many captive settings and are threatened throughout their native ranges. Many zoos support in situ conservation projects and provide opportunities to conduct ex situ research in controlled settings with comparably approachable animals. Zoo elephant projects may facilitate fieldwork with free-ranging elephants (e.g. development of non-invasive sampling and analytical tools), which may then also improve the husbandry of elephants in human care. Free-ranging elephants also benefit from drug therapies and veterinary care when they are orphaned, kept as working elephants or brought in as rehabilitation casesespecially as human-elephant conflicts become more common as a result of ever-expanding human populations. Much has been learned about the basic biology and husbandry needs of elephants but, often, the more we learn, the more questions arise. There are physiological differences between African and Asian elephants, and this should affect the management of these animals. This paper will provide brief overviews of the current state of knowledge regarding the pharmacology, nutrition, reproduction, sensory biology and diseases (primarily elephant endotheliotropic herpesvirus infections) relevant to elephants with recommendations for future research.
Free-ranging African elephants are highly social animals that live in a society where age, size, ... more Free-ranging African elephants are highly social animals that live in a society where age, size, kinship, and disposition all contribute to social rank. Although captive elephant herds are small and largely comprises of unrelated females, dominance hierarchies are common. The goal of this study was to delineate how the behavior of captive female African elephants varies with respect to age and social rank based on a combination of keeper questionnaires and behavioral observations. ''Body movements'' and ''trunk to'' behaviors of 33 nonpregnant female African elephants housed at 14 North American zoos were recorded over 8 hr. Keepers at each facility also rated each elephant based on a series of questions about interactions with herdmates. The assessment of social rank based on observations correlated strongly with ranks assigned by keepers via the questionnaires. Observations and questionnaire responses indicated that body weight of the female, and to a lesser extent age, were significantly related to rates and types of ''body movements'' and that these demographic factors dictate the captive elephant hierarchy, similar to that observed in the wild. Many of the observed ''body movements,'' such as back away, displace, push, and present,
Abstract: Controlling beaver (Castor canadensis) populations is a problematic issue for wildlife ... more Abstract: Controlling beaver (Castor canadensis) populations is a problematic issue for wildlife managers in North America. Management of beaver can be facilitated by determining sex ratio of a population, but this requires ready identification of gender for live and harvested ...
Human–wildlife conflict (HWC) is a pervasive, global conservation issue that occurs whenever inte... more Human–wildlife conflict (HWC) is a pervasive, global conservation issue that occurs whenever interactions between people and wildlife result in a negative outcome for either or both parties or the resources upon which they rely. Humans are impacted by wildlife either directly through their survival or health, or indirectly through damage to their food resources or property. Alleviating HWC has relied upon means from the individual to the population scale. Problem animals can be killed, relocated, or trained to avoid human habitations. Animal populations can be reduced through lethal or non-lethal means. Lethal control or relocation often have consequences such as biodiversity loss, unforeseen trophic cascades, and other ecologically detrimental effects. In many cases, the preference may be to keep the animals in question in the region but to reduce their impact on humans. In such situations, barriers can be constructed but these also have potential negative ramifications for other species as well as high costs for construction and maintenance. For invertebrate pests, a push–pull integrated pest management strategy has become increasingly popular. Chemical signals in the form of a natural repellents and attractants serve to keep pests away from crops and attract them to other areas, often traps. For vertebrates, the lack of known chemical signals hampers this approach and furthermore, the lethal trapping of individuals often is undesired. However, biological fences in concert with training animals to avoid the conflict area (e.g., crop or livestock) have potential for reducing HCW, especially for longer-lived, medium- to large-sized vertebrates. In lieu of using natural signals with known function, the proposition is to invoke a novel odor that would be unusual in the range of the problem species. Such an odor would be associated with strongly aversive stimuli near points of conflict and used as a warning of such a stimulus for future encounters. This novel scent fence would elicit anxiety and arouse a memory of discomfort and fear in the animal, motivating it to move away from the area without another interaction with the aversive stimulus. The odor would create an atmosphere of unease and avoidance rather than be the repellent itself. This approach provides further impetus for understanding better the chemical communication and the specific chemical signals used by vertebrates. In advance of those discoveries, odors may be useful as part of an aversive conditioning program to alter movement patterns of animals and keep them away from crops and livestock.
Uploads
Papers by Bruce Schulte