Zoo Biology 33: 403–410 (2014)
Diurnal and Nocturnal Activity Budgets of Zoo Elephants in an Outdoor Facility Kristina M. Horback,1* Lance J. Miller,2 Jeff R. M. Andrews,3 and Stan A. Kuczaj II4 1
Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 2 Chicago Zoological Society—Brookﬁeld Zoo, Brookﬁeld, Illinois 3 Department of Zoological Operations, Busch Gardens Tampa, Tampa, Florida 4 Department of Psychology, University of Southern Mississippi, Hattiesburg, Mississippi The present study examined the activity budgets of 15 African elephants (1 bull, 6 cows, 2 male juveniles, 2 female juveniles, and 4 male calves) living at the San Diego Zoo Safari Park during the summers of 2010 and 2011. Onsite behavioral data (n ¼ 600 hr) were collected for approximately 12 weeks from 0400 to 0830 and 1100 to 2400 during the 2010 and 2011 summer season. Foraging was the most common behavior state during the day followed by resting, and walking. During the evening hours, the elephants spent majority of their time foraging, resting, and sleeping. The average rate of self‐maintenance behavior events (dust, wallow, etc.) increased from 0600 to 0700, 1100 to 1500, and from 1700 to 1900. Positive social behavior events (touch other, play, etc.) remained high from 0500 to 2300, with peaks at 0600, 1300, 1500, and 1900. Negative social events occurred at low rates throughout the day and night, with peaks at 0600, 1900, and 2200. The majority of positive behavior events during the daylight and nighttime hours involved the mother‐calf pairs. Furthermore, the calves and juveniles initiated approximately 60% of all social events during the daytime and 57% of all social interactions at night. The results of this study demonstrate the differences between diurnal and nocturnal activity budgets of a multi‐age and sex elephant herd in a zoological facility, which highlights the importance of managing elephants to meet their 24 hr behavioral needs. Zoo Biol. 33:403–410, © 2014 Wiley Periodicals, Inc. 2014.
Keywords: activity budget; African elephant; animal management; animal welfare; behavioral needs; Loxodonta africana; zoological institution
INTRODUCTION Determining how zoo animals allocate their time throughout a 24‐hr period often provides useful information for animal management (e.g., training, enrichment, social groupings, and exhibit design). Currently, there are approximately 171 female and 73 male African elephants (Loxodonta africana) on exhibit in the North American zoological institutions [Olson, 2011]. Management and husbandry of African elephants in zoos is particularly difﬁcult due to the multifaceted requirements of adequate exhibit size, compatible social grouping, physical management (e.g., free or protected contact), and individual health care [Clubb and Mason, 2002; Veasey, 2006; Mason and Veasey, 2010]. The relaxation of selective pressures seen in zoos (i.e., no predation and limited parasitism) may alter wild behavior patterns. Therefore, making direct comparisons between wild and zoo animals may be misleading. In order to comprehensively assess the welfare of elephants in zoos, researchers
© 2014 Wiley Periodicals, Inc.
may monitor behavioral indicators of health. For example, play behavior occurs when an animal’s primary needs (i.e., food, comfort, safety) have been satisﬁed; therefore, monitoring positive social behaviors may be a sensitive indicator of welfare [Oliveira et al., 2010]. While elevated levels of stereotypy or aggression may indicate, or result in, poor welfare [Mason and Latham, 2004; Hutchins, 2006], other behavior categories such as foraging, self‐maintenance, Conﬂicts of interest: None. Correspondence to: Kristina M. Horback, Swine Teaching and Research Center, New Bolton Center, 505 Byrd Road, Kennett Square, PA 19348. E‐mail: [email protected]
Received 17 October 2013; Revised 06 June 2014; Accepted 02 July 2014
DOI: 10.1002/zoo.21160 Published online 11 August 2014 in Wiley Online Library (wileyonlinelibrary.com).
404 Horback et al. and resting have less clear welfare implications. Although it is difﬁcult for zoological exhibit designers to construct environments that mimic those of their wild counterparts, diurnal activity patterns of feeding and socializing similar to wild activity budgets have been reported in zoo herds [Adams and Berg, 1980; Stoinski et al., 2000; Rees, 2008]. Wild African elephants feed on a variety of low quality vegetation (e.g., grass, branches, and roots) and thus allocate the majority of their alert hours foraging [60–80%: Wyatt and Eltringham, 1974; Shepherdson, 1999; Clubb and Mason, 2002]. These sustained periods of walking for the sake of grazing are interspersed with bouts of social interactions and self‐maintenance behaviors (e.g., dust, wallow, rub) [Wyatt and Eltringham, 1974; Douglas‐ Hamilton and Douglas‐Hamilton, 1975; Moss, 1988]. In order to encourage the performance of such natural behavior patterns, the Association of Zoos and Aquariums recommends the provision daily browse, as well as sand or soil to allow dust bathing and mud wallowing, and durable objects (e.g., rock structures, trees) for rubbing and scratching behavior [AZA, 2011]. While the AZA recommends outdoor housing of at least 167.2 m2/elephant, with an additional 83.6 m2 for each additional elephant, enclosure sizes vary considerably among US zoos [Clubb and Mason, 2002]. In addition, the amount of time that zoo elephants are maintained outdoors depends on the regional climate, enclosure design (e.g., free access to water), and management practices (e.g., keeper hours). Such variation in the management and husbandry practices of elephants directly effects how the animals allocate their time (i.e., activity budget). Environments of zoo elephants should be physically and socially complex both during and after zoo operating hours in order to sufﬁciently meet their 24 hr behavioral needs. For example, unrestricted enclosure access at night [Brockett et al., 1999; Wilson et al., 2006] has been shown to facilitate afﬁliative social behavior and exhibit use in a herd of three adult female African elephants.
Maintaining the natural family herd in zoos is often difﬁcult due to limited accessibility and appropriate enclosure size. The AZA recommends that an institution keep at least three cows as an appropriate social group [AZA, 2011]; while others suggest that six cows are needed to meet the social needs of elephants [Roocroft and Zoll, 1994]. In the wild, maternal family units can range from 4 to 12 closely related adult females and their offspring [Douglas‐Hamilton and Douglas‐Hamilton, 1975; Moss, 1988]. The creation and maintenance of these strong social bonds, including allomothering, has been reported to occur in unrelated zoo elephants [Garaï, 1992]. Maintaining a cohesive elephant herd in zoos is essential given that social housing is recognized as a highly effective enrichment which may improve welfare [Rees, 2009]. The husbandry and management of zoo elephants requires the provision of adequate environmental complexity and space, as well as appropriate social grouping of age and gender whenever possible. Examining the 24 hr activity budget of a multi‐aged African elephant herd in a zoological setting could facilitate animal welfare efforts based on the occurrence of natural behaviors and standard proportions of behavioral activity. MATERIALS AND METHODS Focal Subjects The subjects for this study were 15 African elephants (Loxodonta africana) exhibited at the San Diego Zoo Safari Park in Escondido, California (Table 1). From May 2010 through January 2011, this herd consisted of one adult male, six adult females, two male juveniles, two female juveniles, and four male calves (age class according to Lee ). In January 2011, another male calf was born into the herd and a second bull male was given access to certain females and their corresponding offspring. Behavioral data were not collected on these two additional elephants as the objective of this study was consistency of behavior over the two years. The
TABLE 1. Gender, date of birth, age class, and lineage of the African elephants observed during the summers of 2010 and 2011 Elephant
E1 E2 E3 E4 E5 E6 E7 E8 E9 E10 E11 E12 E13 E14 E15
M F F F F F F M F M F M M M M
est.1/1/1990 est.1/1/1990 est.1/1/1990 est.1/1/1990 est.1/1/1990 est.1/1/1990 est.1/1/1990 2/23/2004 9/11/2006 3/11/2007 9/19/2007 3/13/2009 2/14/2010 4/12/2010 5/12/2010
Adult Adult Adult Adult Adult Adult Adult Juvenile Juvenile Juvenile Juvenile Calf Calf Calf Calf
Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown E1 E1 E1 E1 E1 E1 E1
Unknown Unknown Unknown Unknown Unknown Unknown Unknown E5 E6 E3 E7 E6 E5 E2 E7
Diurnal and Nocturnal Activity Budgets of Zoo Elephants
date of birth for all adults is estimated, as this wild herd was transferred from Kruger National Park in South Africa to Swaziland in 1994, before being rescued from a scheduled cull and ﬁnally transferred to North America in August 2003. Facility The elephant enclosure at the San Diego Zoo Safari Park contains two indoor barns (113.8 m2) and a 14,449.3 m2 outdoor exhibit of various topography (dirt, rock, mud, grass) and includes accessories of trees, shade structures, and a bathing pool. The social grouping of the herd ranged from 15 individuals present in the same large outdoor exhibit, to smaller subgroups of a single adult female and her offspring. The facility was open to the public from 0900 to 1700 every day. Data Collection Onsite behavioral data were collected for approximately 12 weeks from late May to early August during the summers of 2010 and 2011. Observations were recorded in the perimeter section of the elephant exhibit, which is closed off to the public. This enabled the observer to follow and track each individual when they traveled out of public view. During 15 min focal follows, behavior events were recorded using an
all‐occurrence focal sampling technique, while the behavior state of the focal individual at each one minute interval was recorded using instantaneous sampling method [Altmann, 1974; Martin and Bateson, 1993] (see Table 2 for operational deﬁnitions). Each subject was recorded for two separate observation periods per day, resulting in 30 min of behavioral data per subject per day. The daytime data collection occurred from 0400 to 0900 and 1100 to 1600 while nighttime data were collected from 1700 to 2100 and 2100 to 0100. Behavior data were not collected on the herd while the animal keeper staff cleaned the enclosures from 0900 to 1100. In addition, individual behavioral data were only collected on elephants not involved in training activities from 1500 to 1600. The elephants were maintained under similar conditions (i.e., exhibit space, social group, time of day for feeding and training) during the corresponding time blocks. Data were collected during 20 day shifts and 20 night shifts for both 2010 (n ¼ 300 hr data) and 2011 (n ¼ 300 hr data). The full 600 hr of data from both summers were evenly split between daytime (n ¼ 300 hr) and nighttime data (n ¼ 300 hr). This resulted in a total of 40 hr of observational behavior data per individual. The order in which the subjects were observed was determined prior to the data collection period using a randomized computer sequence using the Microsoft Excel1 program.
TABLE 2. Operational deﬁnitions for behavior states and events recorded Instantaneous behavior states Forage Self‐maintenance Rest Positive social Negative social Walk Sleep Out of view All‐occurrence behavior events Self‐maintenance Bathe Dig Dust Rub Wallow Positive social Play Share food Share object Spar Touch other Negative social Bite Charge Chase Hit Stereotypic Sway
Engaging in behaviors related to feeding, trunk to ground inspection, etc. Can be walking, running, or standing still Engaging in wallowing, bathing, or sustained dusting and rubbing of body with environment (ground substrate or walls and trees) Lying in lateral incumbent position or standing while not engaging in behaviors Engaging in trunk wrestling, sparring and other behaviors related to play Engaging in sustained hitting, biting, or ramming behaviors Only engaging in behaviors related to walking, trotting, running, etc. Lying in lateral incumbent position, not alert Individual is not in view at the time point Submerse whole body in water Use trunk or foot movements to stab into ground Throw browse, dirt, dung, hay, mud, or sand on self Brush head or body against a wall, tree or object Lie down in mud, dirt or sand Trunk wrestling, shoving, butting, bullying each other Consume from the same food pile, simultaneously More than one elephant simultaneously handling the same object Head to head contact between two elephants. Pushing trunks, tusking, shove, wrestle or trunk entwine with another elephant Initiation of head or body contact with another elephant The aggressor puts the tail or other body part of another elephant in its mouth Rapidly approach another animal with trunk tucked under head, and head up One elephant runs after another. The pursuer is attempting to reduce the separation between animals The aggressor charges/rams another elephant with its head, trunk, or limb Move body side to side repeatedly; usually with all four feet on the ground
406 Horback et al. Although all behavioral data were collected by a single observer, a second observer recorded 1 hr of observational data for each member of the herd, resulting in 15 hr of behavioral data analyzed for inter‐observer reliability (IOR > 0.90). In order to verify that behaviors were being coded on a consistent level throughout the summer (i.e., no observer‐fatigue), intra‐observer reliability was assessed through repeated coding of two 20‐min video segments of the herd ﬁlmed in the spring of 2011 (r > 0.95). All procedures described were reviewed and approved by the Zoological Society of San Diego IACUC under proposal #10‐004. Data Analysis The proportion of visible scan samples that each elephant was recorded to be in the eight behavior states was calculated for the two summers. Each elephant also received a rate per hour of all behavior events based on the proportion of visible scans. The average rate of each behavior event and proportion observed in each behavior state recorded in 2010 was compared to 2011 data to assess individual consistency between the years. There was not a signiﬁcant difference (Wilcoxon signed‐ranks test, P > 0.05) in individual behavior states or event rates between the 2 years for all 15 elephants. After this reliability check, the behavior states and event rates were averaged over the two summers for each individual based on the hour of the day. Behavioral categories were used to examine differences in diurnal and nocturnal self‐maintenance, positive social and negative social behavioral events (Table 2). Rates were calculated for these categories based on the total number of events observed, divided by the duration of time the elephants were visible within each condition. The behavior event of swaying was not observed throughout the 600 hr of data collection and therefore was not included in further analysis. Data were divided into two categories: diurnal (0600– 0830, 1100–1759) and nocturnal (1800–2400, 0400–0559). This separation of data was based on almanac records of sunrise and sunset for Escondido, CA in the summer of 2010 and 2011 [Sunrise Sunset Calendar, 2011]. Wilcoxon signed ranks tests with a signiﬁcance level set at P < 0.05 (IBM SPSS 17.0) were conducted in order to compare diurnal versus nocturnal elephant activities. RESULTS
TABLE 3. Average SD proportion of visible scans all elephants were observed in each behavior state during daylight (0600–1759) versus evening (1800–0559) hours Behavior state Forage Self‐maintenance Rest Positive social Negative social Walk Sleep Out of view
52 11.6 2.6 1.2 31.3 8.3 2.9 3.1 0.0 0.0 9.2 2.2 0.8 1.4 0.7 0.6
48 17.2 0.8 1.3 24 2.6 2.4 2.6 0.0 0.0 5.3 1.8 17.2 9.9 0.7 0.7
Z (P‐value) 1.8 3.2 3.3 1.3 0.0 3.3 3.4 0.0
(0.07) (0.001) (0.001) (0.26) (1.0) (0.001) (0.001) (1.0)
Note. Z ¼ Wilcoxon signed ranks test; P < 0.05 two‐tailed test in boldface.
hours (Table 3). Foraging was the most common behavior state during the day (M ¼ 52 11.6%) followed by resting (M ¼ 31.3 8.3%), walking (M ¼ 9.2 2.2%), self‐maintenance (M ¼ 2.6 1.2%), positive social (M ¼ 2.9 3.1%), and sleeping (M ¼ 0.8 1.4%). During the night hours, the most common behavior state was foraging (M ¼ 48 17.2%), followed by resting (M ¼ 24 2.6%), sleeping (M ¼ 17.2 9.9%), walking (M ¼ 5.3 1.8%), positive social (M ¼ 2.4 2.6%), and self‐maintenance (M ¼ 0.8 1.3%) (Fig. 1). The average percent of time elephants were recorded to be in a negative social state was zero for both diurnal and nocturnal activity budgets. Behavior Events The rate of self‐maintenance behaviors (Z ¼ 2.1, n ¼ 15, P ¼ 0.04) and positive social behaviors (Z ¼ 2.5, n ¼ 15, P ¼ 0.02) were signiﬁcantly higher during the daylight hours (self‐maintenance: M ¼ 10.3 6.7, positive social: M ¼ 25.4 5) than during the night hours (self‐ maintenance: M ¼ 2.5 2.6, positive social: M ¼ 14.5 9.7). There was not a signiﬁcant difference (Z ¼ 1.2, P ¼ 0.2) between diurnal (M ¼ 0.4 0.2) and nocturnal (M ¼ 0.2 0.3) rates of negative social behaviors among all elephants (Table 4). The average rate of self‐maintenance behavior events (dust, wallow, etc.) increased from 0600 to 0700, 1100 to 1500, and from 1700 to 1900. Positive social behavior events (touch other, play, etc.) remained high from 0500 to 2300, with peak at 0600, 1300, 1500, and 1900. Negative social events occurred at low rates throughout the day and night, with peaks at 0600, 1900, and 2200 (Fig. 2).
All 15 elephants spent signiﬁcantly more time during the daylight hours in the behavior state of self‐maintenance (Z ¼ 3.2, n ¼ 15, P < 0.01), rest (Z ¼ 3.3, n ¼ 15, P < 0.01), and walk (Z ¼ 3.3, n ¼ 15, P < 0.01). They also spent signiﬁcantly more time sleeping during the night hours (Z ¼ 3.4, n ¼ 15, P < 0.01). There were no signiﬁcant differences observed for the behavior states of forage, positive social, and negative social between the day and night
During the daylight hours, 98.8% of all social behavior events were positive. Of these, 32% were initiated by a mother cow toward her calf or juvenile, while 31.7% were initiated by a calf/juvenile toward their own mother. Of the remaining positive social behaviors during the day, 22.5% were calf/juvenile to another calf/juvenile, 5.6% were initiated by a calf/juvenile toward a non‐mother adult, 4.5% were initiated by an adult toward a non‐relative calf/
Diurnal and Nocturnal Activity Budgets of Zoo Elephants
Average percent of observation time (n ¼ 600 hr) elephants were recorded to be in each behavior state based on hour of the day.
juvenile, and 3.8% were adult to adult positive interactions. The few negative social events during the day were predominantly (47.2%) mother to calf interactions (e.g., trunk slaps during weaning), followed by calf/juvenile toward another calf/juvenile (30.6%). There were only four events initiated by an adult toward another adult (11.1%) and four initiated by an adult toward a non‐related calf/juvenile (11.1%). There were no negative social behaviors recorded during the day of a calf toward its mother or a calf toward another adult. During the nighttime hours, 98.4% of all social events were positive. Similar to the daytime social behaviors, the majority of positive events (33.5%) were mother to calf/ juvenile followed by the reciprocal of calf/juvenile to mother (31.7%). Of the remaining positive social behaviors during the night, 22% were calf/juvenile to another calf/juvenile, 5.1% were initiated by an adult toward a non‐relative calf/ juvenile, 4.4% were adult to adult interactions and only 3.4% were initiated by a calf/juvenile toward a non‐mother adult. Like the daytime interactions, the majority of negative social events during the evening hours were initiated by a mother toward their offspring (51.2%), followed by calf‐to‐calf TABLE 4. Average rate per hour SD all elephants were observed to display behavior events during the daylight (0600– 1759) and evening (1800–0559) hours Behavior events
Self‐maintenance Positive social Negative social
10.3 6.7 25.4 5 0.4 0.2
2.5 2.6 14.5 9.7 0.2 0.3
2.1 (0.04) 2.5 (0.02) 1.2 (0.2)
Note. Z ¼ Wilcoxon signed ranks test; P < 0.05 two‐tailed test in boldface.
negative interactions (26.8%). There were only three (7.3%) negative events initiated by an adult toward another adult at night, and two (4.9%) of each calf‐to‐mother, calf‐to‐adult, and adult‐to‐calf negative interactions recorded at night. DISCUSSION Throughout the summers of 2010 and 2011, foraging was the most common behavior state during the day, followed by resting, and walking for both adults and calves/juveniles. Both adult and young elephants spent the majority of their daytime activity foraging followed by resting, and walking, and spent the majority of their time at night foraging, resting, and sleeping. This distribution of diurnal and nocturnal behavior is similar to previous activity budgets observed in herds of other zoological institutions. In examining the effects of feeding enrichment on daytime behavior of three female African elephants housed at Zoo Atlanta, Stoinski et al.  reported the animals fed 47–51.5% of the daylight observation time, and walked 6.3–6.6% of the time from 09:00 to 09:30. Rees  reported eight Asian elephants at the Chester Zoo (UK) to feed 27.4–41.4%, rested 22.9– 42.0%, and walked 6.1–19.2% of observation time between 10:00 and 14:00 hr. While Schmid et al.  report that six female Asian elephants of the Münster Zoo spent on average 37.7% (range 29–64%) of observation hours (0800–1800) foraging and drinking. When available, browse may be provided to zoo elephants as a both a nutritional supplement and an enrichment item which can be manipulated and eaten throughout the day and into the evening hours. The peak of foraging for this herd occurred when the keeper staff provided browse from 1100 to 1200, and again from 1600 to 2200 with no humans on‐site. Zoo Biology
408 Horback et al.
Fig. 2. Change in average rate (#/hr) of self‐maintenance, positive and negative social behavior events during diurnal and nocturnal (shaded) observation periods.
In their recent study of the activity budget of an African elephant mother‐calf pair living at the Toledo Zoo, Posta et al.  reported changes in the behavior based on indoor versus outdoor housing, day (0800–1659) versus night (1700–0800) observations, and throughout the seasons. In comparison to the conditions of the present study, when this pair was housed outdoors (916 m2) during the summer they reduced time spent feeding and greatly increased time spent walking during the evening hours. The opposite change in nocturnal activity budget was recorded for the elephants at San Diego Safari Park, with increasing time spent foraging and decreasing time spent walking around enclosure. This difference is most likely due to the large difference in enclosure size (916 m2 vs. 14,449 m2) and social complexity, as well as the potential difference in browse provision. A caveat to the Posta et al.  study is the large proportion of time the mother (21%) and calf (36%) were out of view for video observation when outdoors at night. In comparison, the adult and young elephants of the present study were only out of view for a total of 0.6% at night during real‐time data collection. Although there was not a single observation of swaying recorded during the 600 hr of data collection other stereotypic behaviors reported in captive elephants (e.g., head bobbing, route tracing, trunk swinging, etc.) were not included in the ethogram, nor were they recorded ad libitum. The lack of swaying by these elephants may be due to seasonal inﬂuence as all data were collected in the summertime and swaying has been reported to be negatively correlated with environmental temperature [Rees, 2004]. It is also possible that the stereotypic behaviors were not observed in this herd was due to animal management practices at this facility (i.e., large space, increased social interactions, increased time with young) [Greco, 2014]. All ﬁfteen elephants were given free Zoo Biology
access to the entire outdoor exhibit throughout the day and night of the summer seasons. Maternal family units foraged and walked throughout the night until the young began to sleep around 2300. Around 0500–0600 the maternal units would wake up in the outdoor enclosure and display sustained periods of resting, gradually increasing foraging behavior. In the wild, African elephants tend to sleep 3–5 hr/night [Moss, 1988], while elephants in zoos have been reported to sleep for 4–6.5 hr/night [Tobler, 1992; Brockett et al., 1999]. Similar to previous activity budget analyses of zoo elephants, the elephants in this study displayed nocturnal peaks in foraging. Three females housed at Zoo Atlanta were reported to show an increase in nocturnal feeding from 1800 to 2200 [Brockett et al., 1999], as well as from 1700 to 0000 in a follow‐up study of the same animals [Wilson et al., 2006]. The foraging spike during the late morning hours of this study is directly related to the animal care management schedule. At 1100 each day, the herd was provided the afternoon feed in the form of piles of browse, beet pulp, and pellet diet. The elephants were recorded to maintain high foraging levels (>45%) for the 10 hr following this afternoon browse provision. There are noticeably large drops in the rates of positive social and self‐maintenance behavior events at 0800 when the keepers arrive to the barn but are not interacting with the elephants, during 1100–1200 when non‐focal elephants were engaged in training sessions, and at 1500 when the keeper staff makes ﬁnal checks on the herd before leaving for the day. Throughout these times, the elephants are often oriented toward or directly approaching keeper activity in the perimeter of the enclosure, and thus their attention is shifted from conspeciﬁcs to humans. The frequency of dusting behavior in African elephants is positively correlated with environmental temperature
Diurnal and Nocturnal Activity Budgets of Zoo Elephants
[Rees, 2002]. This vital self‐maintenance behavior facilitates body temperature regulation, and protects the skin from the sun and parasites [Feldhamer et al., 1999; Elder and Rodgers, 2009]. Similar to other studies [Rees, 2008], dusting occurred at all times of the day, with peaks observed at 0600, 1200–1400, and 1700–1900. Following the departure of the staff, there was a large increase in the rate of social play behavior observed from 1600 to 2000 for the adults, and 1800–2000 for the juveniles and calves. This late afternoon spike in positive social behavior, after park visitors have departed, has been reported in other zoo herds [Kuhme, 1963]. Brockett et al.  also reported an increase in social behavior from 1900 to 2100 among three juvenile female elephants in 1992, as well as an increase from 1800 to 2000 in 1994. In addition, the herd engaged in very low rates of negative social behaviors (average < 0.1% of observation time) similar to the low levels of aggression seen in other studies of African elephants in both a wild [Archie et al., 2006] and zoological setting [Wilson et al., 2006]. The juveniles and calves are often the focus of activity for the herd and are an important source of social cohesion. Interaction with calves and young juveniles provides young females the opportunity to develop maternal skills [Moss, 1988; Clubb and Mason, 2002]. As reported in wild herds, the adult female elephants maintained relationships with their offspring through frequent physical contact and sharing of food, and alternatively, interacted infrequently with other adult females [Moss and Poole, 1983]. Juvenile and calf elephants are relatively rare in zoos, and most facilities house elephants belonging to just one or two age classes [Clubb and Mason, 2002]. In contrast, the herd of the present study was made up of multiple age classes and genders, allowing for diverse social interactions. The majority of positive behavior events during the daylight and nighttime hours involved the mother‐calf pairs. Furthermore, more than half of all diurnal and nocturnal social interactions were initiated by a calf or juvenile. The patterns of positive and negative social interactions among a herd establishes the individual relationships which underlie the overall group structure. The high levels of foraging and social interactions, coupled with very low levels of aggression, suggest that this herd has adequate opportunity to express natural behavior patterns—a deﬁning feature of welfare (i.e., ﬁve freedoms: Webster ). The elephants were observed to spend more than 50% of observation time in an active behavior state (i.e., not rest or sleep) from 0800 to 2200. This included relatively consistent rates of positive social interaction until late in the evening. All this taken together suggests that it could be important to keep elephant groups together throughout the night, providing opportunities to engage in species‐appropriate behavior. Separating animals and holding them in individual stalls would remove the behavioral opportunities afforded to elephants allowed to remain in social groups throughout the night. When managing elephants it is important to consider
the full 24 hr days rather than only the typical 8–10 hr animal care staff are present.
CONCLUSIONS 1. While examining summertime activity patterns in a herd of
African elephants living at the San Diego Zoo’s Safari Park, foraging and resting were recorded to be the most common behavior states during both the daylight and nighttime hours. 2. Peaks in the rate of self‐maintenance behaviors occurred from 0600 to 0700, 1100 to 1500, and from 1700 to 1900. Positive social behavior events remained high from 0500 to 2300, with peaks at 0600, 1300, 1500, and 1900. Negative social events occurred at low rates throughout the day and night, with peaks at 0600, 1900, and 2200. 3. Given that elephants engage in different behaviors throughout a 24‐hr period, it is important to manage elephants in a way that allows them to engage in species‐appropriate behavior throughout the entire day.
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