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Daily Patterns of Activity in the Spotted Hyena

Joseph M. Kolowski, Dijana Katan, Kevin R. Theis, Kay E. Holekamp
DOI: http://dx.doi.org/10.1644/06-MAMM-A-143R.1 1017-1028 First published online: 20 August 2007


We used long-term (2- to 15-h) focal-animal sampling (“follows”) and supplementary behavioral observations of adult spotted hyenas (Crocuta crocuta) from 3 separate social groups within the Masai Mara National Reserve, Kenya, to investigate the degree to which sex, social rank, and human disturbance influenced hyena activity patterns, movement rates, and timing of den use. Hyenas followed for composite 24-h cycles were active during 31.5% ± 2.7% SE of the 24-h period. During hours of darkness (1900–0600 h) hyenas spent 53.0% ±4.1% of their time active, and 96.2% ± 0.9% of all activity occurred from 1800 to 0900 h. Mean movement rate during this period was 928 m/h ±104 SE, and was 584 ± 64 m/h throughout the 24-h period. Distance traveled during a 24-h period averaged 12.4 km. Male spotted hyenas tended to be more active than females, particularly during the morning (0700–1100 h), and also tended to exhibit higher movement rates. Neither rates of activity nor movement varied with social rank, but low-ranking females spent more time feeding than did high-ranking females. Finally, female hyenas in territories with daily livestock grazing and high tourist visitation rates showed lower activity and den use than hyenas in an undisturbed territory during the times of day when human activity coincided with potential hyena activity. Specific times of day when activity was reduced indicated that livestock grazing, not tourist activity, was probably responsible for observed shifts in activity. We discuss possible indirect costs associated with observed alterations in timing of den use and activity.

Key words
  • activity
  • cattle
  • Crocuta crocuta
  • human disturbance
  • livestock grazing
  • Masai Mara
  • movement rates
  • sex differences
  • spotted hyena

As in other mammals, the daily activity patterns of terrestrial carnivores result from both endogenous biological rhythms and behavioural adaptations to a changing environment (Daan 1981; Rusak 1981). Optimal patterns of activity reflect the influence of daily variation in temperature (Avenant and Nel 1998; Garshelis and Pelton 1980), predation risk (Drew and Bissonette 1997; Geffen and Macdonald 1993; Lima and Dill 1990), and prey availability (Ferguson et al. 1988; Garshelis and Pelton 1980; Larivìere et al. 1994; Lode 1995). However, individual characteristics such as sex and reproductive condition also may influence patterns of daily activity (Daan and Aschoff 1982; Lariviere and Messier 1997; Paragi et al. 1994; Zalewski 2001). Furthermore, in gregarious carnivores whose societies are structured by linear dominance hierarchies, social status also may contribute to variation in activity patterns. Given increased human presence on landscapes worldwide, large carnivores have been shown to alter their natural patterns of activity to avoid human disturbances ranging from tourist or recreational activity (Machutchon et al. 1998; Olson et al. 1998) to direct exploitation by hunting (Andelt 1985; Kitchen et al. 2000). Therefore, where present, humans are likely to further influence observed activity patterns of free-living carnivores. Here we examine effects of these variables on activity patterns observed among spotted hyenas (Crocuta crocutd).

All 4 extant species in the family Hyaenidae are reported to be primarily nocturnal (Bothma and Nel 1980; Henschel 1986; Kruuk 1976; Mills 1984, 1990). However, the activity pattern of the spotted hyena, a gregarious carnivore found throughout sub-Saharan Africa, appears to be the most flexible, with activity often extending into periods of daylight (Kruuk 1972), or even occurring at midday (Rainy and Rainy 1989). The only systematic data describing activity patterns of Crocuta come from the Serengeti ecosystem in Tanzania (Kruuk 1972) and from South Africa (Henschel 1986; Mills 1990). In both locations, hyenas exhibited a strongly nocturnal activity pattern with somewhat reduced activity during the middle of the night (Kruuk 1972; Mills 1990). However, within the Serengeti, the timing of evening activity peaks varied unpredictably over the course of months or weeks (Kruuk 1972). Furthermore, overall levels of hyena activity and movement rates were approximately twice as high in the Kalahari as in the Serengeti (Kruuk 1972; Mills 1990). Thus, patterns of activity are clearly variable in this species, yet sources of this variation remain unclear. Although Henschel (1986) documented sex differences in activity and movement of Crocuta, the influence of social rank on these variables has yet to be investigated.

Our long-term study of spotted hyenas provides an opportunity to document in detail the activity patterns and movement rates of individual male and female C. crocuta of various social ranks, and to investigate the influence of human presence on hyena activity. Livestock grazing already has been shown to influence patterns of space utilization by the hyenas in our study population, and additional effects of grazing on hyena activity patterns were suggested by those data (Boydston et al. 2003b); however, the effect of daytime cattle grazing on carnivore activity patterns has not been investigated in any study system.

Our goals here were to describe the general activity pattern and time budget of free-living C. crocuta in Kenya, to investigate the influence of sex and social rank on activity patterns and time budgets, and to investigate the effects of daytime human disturbance on hyena activity patterns and timing of den use. Because reproductive success among male hyenas is associated with their frequency of social interaction with the group's breeding females (East et al. 2003; Szykman et al. 2001), we expected that movement and activity rates of males would exceed those of females, because of a need to regularly interact with as many females as possible. Because hyenas of low social rank have low priority of access to food resources, we expected they would exhibit higher activity and movement rates than hyenas of high rank. Finally, we were able to assess the influence of human disturbance on activity patterns of hyenas by comparing activity between members of neighboring social groups that differed in their exposure to both livestock grazing and tourist visitation during daylight hours. If activity of hyenas is affected by human presence on the landscape, then we expected activity rhythms to differ between these groups; specifically, activity and den use of hyenas in disturbed areas should be reduced when humans and cattle are present.

Materials and Methods

Study area.—Our study was conducted from 2001 to 2004 in and around the Masai Mara National Reserve (1,500 km2; hereafter, the Reserve) in southwestern Kenya (1°40′s, 35°50′E). The Reserve consists primarily of rolling grassland and scattered bushland (predominantly Croton and Euclea species), with riparian forest along the major watercourses. Average annual rainfall in the study area from 2001 to 2004 was 1,305 mm. Most rainfall occurs during 2 wet seasons: the “short rains” in November-December, and the “long rains” in March-May. Mean monthly daytime temperatures in 2003 averaged 28.3°C (range = 25.1-32.3°C), with the lowest temperatures occurring from May to July. Monthly nighttime temperatures averaged 13.8°C (range = 12.2-14.9°C). Because of the proximity of our study site to the equator, sunset and sunrise times varied little throughout the year, with sunrise occurring from 0618 to 0648 h and sunset from 1828 to 1858 h.

Study populations.—Spotted hyenas live in social groups called clans, and clan members cooperatively defend a stable group territory. Each clan contains 1 to several matrilines of adult females and their offspring, as well as 1 to several adult immigrant males. Clans are rigidly structured by hierarchical rank relationships (Frank 1986; Kruuk 1972; Tilson and Hamilton 1984), with adult females socially dominant to immigrant adult males (Kruuk 1972; Smale et al. 1993). Subadult individuals of both sexes maintain their maternal ranks as long as they remain in the natal clan (Smale et al. 1993). Although females are generally philopatric (Frank 1986), almost all natal males disperse between the ages of 2 and 5 years (East and Hofer 2001; Henschel and Skinner 1987; Van Horn et al. 2003). Clans of C. crocuta are fission-fusion societies in which individuals travel, rest, and forage in subgroups that typically change in composition many times each day (Holekamp et al. 1997a; Kruuk 1972). Female Crocuta bear 1 or 2 (rarely 3) young in isolated natal dens (Holekamp et al. 1996). Young are typically transferred to a communal den at 2–5 weeks of age, where they reside for the next 7–8 months (Kruuk 1972). The communal den represents the social center of each clan's territory and most clan members visit it regularly. Den-independent young generally continue to nurse from their mothers until they are approximately 11—14 months old (Holekamp et al. 1996).

We monitored adult (>3 years old) members of 3 different clans. The adjacent territories of the Talek East (19.0 km2; 29–35 members) and Talek West (28.4 km2; 47–55 members) clans were both located mainly within Reserve boundaries but partially extended outside the northeastern border of the Reserve into lands occupied by Maasai pastoralists (Fig. 1). The dominant land uses on Maasai-owned land were subsistence pastoralism and wildlife tourism. The Talek region supports the highest density of Maasai settlements along the entire northern border of the Reserve (Reid et al. 2003).

Fig. 1

Territory boundaries (dotted lines) of the 3 monitored spotted hyena (Crocuta crocuta) social groups (clans) in the Masai Mara National Reserve, Kenya. Triangles indicate the 4 main tourist lodges in the study area, open circles represent Maasai villages, and a star indicates the town of Talek. Prey-sampling transects are indicated with checkered lines.

Settlements within 2 km of this northeastern Reserve border supported roughly 12,000 cattle and 16,500 sheep and goats (Kolowski and Holekamp 2006), some of which were grazed illegally within the Reserve. Hyenas from both Talek clans have been killed at villages near the Reserve during livestock depredation attempts (Kolowski and Holekamp 2006). The areas outside the Reserve lying within the 2 Talek territories were grazed year-round by livestock, and included broad vegetation types similar to that in the Reserve, with somewhat reduced woody vegetative cover. Our 3rd study group, the Mara River clan (28–43 members), defended a territory (31.0 km2) >6 km from the Reserve border (Fig. 1). We expected the more isolated Mara River territory to be characterized by lower levels of tourist and grazing pressure than either Talek territory, because the majority of tourist lodges and all Maasai villages are situated outside the Reserve border (Fig. 1).

Ecological comparison between clans.–To assess the relative levels of human disturbance experienced by our study clans, we conducted monthly comprehensive livestock censuses in the Mara River territory (n = 18 months; September 2002-February 2004) and the Reserve portions of both the Talek West (n = 18 months; September 2002-February 2004) and East (n = 11 months; September 2002-July 2003) territories. Censuses involved driving throughout each territory to obtain complete head counts for sheep, goats, and cattle herds. Individual censuses were conducted at 2-h intervals throughout the day, with an initial census conducted as livestock herds entered the Reserve in the morning and a final census conducted as herds left the Reserve in late afternoon. However, censuses at these time intervals were not necessarily conducted on the same day; we completed 1 census during each 2-h interval once a month, with an average of 5 censuses per month (all at different times) in each territory.

As part of a larger ongoing study, behavioral observations of hyenas from each clan were conducted on average 22 days per month throughout the study period. Hyena observation “sessions” were conducted during all hours of the day and night but occurred primarily during the early evening (1730–2000 h) and late morning (0600–0830 h). To describe the timing and relative intensity of tourist use of our clan territories we recorded all instances of tour vehicles approaching hyenas during these sessions. These data were used to identify primary tourist-use periods during the 24-h period and to calculate the frequency of vehicle approaches per hour of hyena observation during these periods in both the Talek and the Mara River territories.

In addition to human disturbance we assessed other ecological variables within each clan territory that might influence hyena activity patterns. We characterized the availability of natural prey to hyenas in each clan by counting all prey occurring along 1-km road transects in all 3 territories. Transects were located in open grassland to facilitate counting and were placed evenly throughout the territory, typically separated by less than 1 km (Mara River n = 24, Talek West n = 11, Talek East n = 13; Fig. 1). We counted all wild ungulates within 100 m of each transect 24 times per month to estimate prey density values for all 3 territories. Because lions are an important source of mortality for spotted hyenas (Kruuk 1972), we also recorded all observations of lions, either alone or interacting with hyenas, and calculated average lion group size and the relative frequency at which lions were observed within each territory.

Communal den use.–The times of day at which females attend the communal den and nurse young may be influenced by human activity. We used 2 different methods to investigate whether the daily timing of den use in the 2 Talek clans (considered together here because of low sample sizes within each clan) differed from that observed in the Mara River clan. First, we utilized den observations lasting several hours to monitor fine-scale timing of den use. Observers arrived at the communal den in the afternoon, before young emerged and before any other hyenas were present, and recorded both the time of arrival at the den of the 1st adult female or subadult, and the time at which den-dwelling young appeared above ground. We compared the Mara River and Talek clans with respect to the median time of 1st arrival and 1st appearance of young using a 2-way test of independence to test for equality of medians (Sokal and Rohlf 1995).

Second, we utilized information collected during shorter-term behavioral observations at communal dens. Observers visited all active communal dens at least once every 2 days during regular morning and evening observation periods (see above). At each visit to a den we conducted an initial scan to record which hyenas, if any, were present at the den at that time. We conducted subsequent scans of hyenas present every 10–15 min until a final scan was conducted before we left the den. We used logistic regression, with time as a single continuous predictor variable, to compare the Mara River and Talek clans with respect to the influence of time on the probability of observing any hyenas at the communal den. We performed separate regressions for each clan within each observation period (morning and evening) and individual model significance was assessed using a likelihood-ratio chi-square test.

Monitoring hyena activity.—We anesthetized 19 adult hyenas (11 females and 8 males) from 2 of the 3 study clans (Mara River n = 10, Talek West n = 9) with tiletamine-zolazepam (6.5 mg/kg; Telazol; W. A. Butler Company, Brighton, Michigan) administered in a dart using a C02-powered rifle (Telinject Inc., Saugus, California), and fitted them with very-high-frequency (VHF) radiocollars (Telonics Inc., Mesa, Arizona). Radiocollared hyenas were from a wide range of social ranks. To describe hyena activity patterns we utilized focal-animal sampling with continuous recording of behavior. These sampling events (hereafter “follows”) lasted 2–15 h and were conducted at all times of day and night with the aid of night-vision binoculars and infrared spotlights. Although Talek East hyenas were included in analyses of timing of den use, they were not followed because of difficult terrain within their territory. Because we were interested in comparing movement rates of males and females without attachment to den sites, and because movements of female hyenas are influenced by the need to return to den-dwelling young (Boydston et al. 2003a), we only followed females without den-dwelling young.

Although we were unable to follow hyenas for complete 24-h periods because of logistical difficulties, we documented the 24-h activity pattern of each individual hyena by observing it during shorter follow segments that together generated a composite 24-h cycle. We attempted to complete this cycle as quickly as possible after its onset, with the average time necessary for completion being 31 days. Because 21% of the follow segments did not contribute to a composite 24-h cycle (e.g., because of death of a hyena or failure of a collar before completion of a cycle), analyses utilizing data from all recorded follow segments (i.e., from composite and incomplete 24-h cycles) are characterized by unequal sample sizes per hour-long time block. All analyses requiring equal sampling throughout the 24-h period utilize only data from composite 24-h cycles.

During each follow, we categorized the behavior of the focal hyena in every minute as traveling, nursing, resting, socializing, feeding, engaging in hunting, miscellaneous activity (standing or sniffing objects or the ground), or interacting with other carnivore species. We considered all behaviors other than resting and nursing as “active.” When individuals were out of sight, we categorized hyenas that were clearly not resting (based on signal fluctuations, auditory clues, or obvious location changes) simply as active,” otherwise we recorded behavior and activity as unknown. We calculated the percent of time each hyena was active and engaged in each behavior during each hour block of each follow segment. Hour blocks with >20 min during which the hyena was out of sight, or activity could not be assessed, were not included in hourly behavior and activity analyses, respectively. Follows were terminated when activity of the focal hyena could not be conclusively determined for >20 consecutive minutes or when the focal hyena was out of sight for >30 min within an hour block. Activity during composite 24-h follows is presented as the percent of the entire 24-h period during which the hyena was active. We also used composite 24-h follows to describe time budgets of hyenas, with the percent of time spent engaged in each behavior calculated out of the total minutes the hyena was in sight during the 24-h period. To determine whether activity of hyenas was affected by human activity, we additionally compared individuals from the Mara River and Talek West clans with respect to percent of total activity exhibited during daylight hours (0700-1800 h), because park regulations prevented public access to the Reserve between sunset and sunrise.

We calculated the length of all bouts of activity and inactivity; we defined the former as periods of at least 5 min of activity bounded on either end by 5 consecutive min of inactivity. We restricted analyzed bouts to those beginning and ending between 1800 and 0900 h to exclude long periods of daytime resting, and lengths of bouts were only calculated for follow segments lasting longer than 4 h. Lengths of bouts were minimum estimates because some follows ended before completion of bouts. We identified cessation of daily activity as the time of morning after which no more than 10 consecutive active min were observed, and we identified onset of evening activity as the 1st afternoon time after which at least 10 consecutive active min occurred.

Because social interactions and group formation may be facilitated among distant hyenas through the use of longdistance vocalizations called whoops (East and Hofer 1991b; Kruuk 1972), we also recorded all whooping behavior by focal hyenas to investigate its temporal distribution. As another measure of clan social activity we recorded the number of hyenas with the focal hyena every 10 min during follows, and further noted group-size changes as possible within each 10 min interval. We then calculated the mean minimum hourly number of changes in group size using all composite 24-h follows.

To determine hourly movement rates, we recorded the locations of followed hyenas every 10 min and calculated straight-line distances between consecutive locations with Animal Movement Analyst (Hooge and Eichenlaub 2000) and Arc View GIS 3.2 (Environmental Systems Research Institute, Redlands, California). Very few locations required the use of telemetry because followed hyenas were in sight, on average, for 98% of follow minutes. We then calculated average hourly movement rates for individuals based on composite 24-h follow cycles. Although we included only hour blocks with at least 4 locations per hour, we collected, on average, 140 of 144 possible locations per 24-h follow cycle.

In addition to the use of composite 24-h cycles to calculate mean percent time active, and mean hourly movement rate for both daylight and the entire 24-h period, we used all individual follow segments to perform additional activity and movement comparisons, with data aggregated into 5 distinct diel periods. We excluded data collected from 1100 to 1400 h because negligible amounts of activity and movement were observed for any individual hyena during this time period. We divided the hours of darkness into 3 periods of equal length (night 1: 1900–2300 h, night2: 2300–0300 h, night3: 0300–0700 h) and categorized the remaining hours as morning (0700–1100 h) and evening (1400–1900 h), based on average time of sunrise and sunset. We averaged hourly activity and movement rates within each of these 5 periods for each individual and made comparisons within time periods based on sex and clan. For comparisons of movement rates between males and females based on these 5 periods, we excluded all hour blocks during which the focal hyena engaged in a nursing bout to control for limitations on movements of females due to nursing demands. However, movement rates of females based on 24-h follow cycles included follows during which nursing behavior was observed.

We categorized social rank for adult females as high or low relative to the median rank of adult females. In analyses involving onset and cessation of activity, the sampling unit was the follow segment but in all other analyses, the sampling unit was the individual hyena. We averaged movement and activity data within sampling periods (e.g., hour or morning period) for individuals that were followed more than once during that period. Because of low sample sizes we compared mean proportions between groups using a nonparametric Mann-Whitney U-test, and compared frequency data using chi-square tests.

Results in units of time are presented as medians because minutes are not on a strictly continuous scale; all other results are presented as means ± SE. Listed P-values are 2-tailed unless research hypotheses generated clear directional predictions for group comparisons. For example, because we predicted males would show higher rates of activity and movement, and spend more time traveling than females, 1-tailed tests were used for these comparisons. Statistical comparisons for all analyses were considered significant at a = 0.05. All statistical analyses were conducted using the software package STATISTICA (StatSoft 2002).


We followed 19 different hyenas (11 females and 8 males) during 100 follow segments for a total of 628 h. The average length of follow segments was 6.3 h ± 3.3 SD. These segments resulted in 22 composite 24-h follow cycles for 16 different hyenas (11 females and 5 males). Four females and 2 males were followed for two 24-h cycles. Twenty-one follow segments did not contribute to a composite 24-h cycle.

General activity.—The daily pattern of hyena activity was largely nocturnal with no clear peaks in activity throughout the night (Fig. 2). In 16 follows of 11 different hyenas the time of cessation of daily activity could be determined, and yielded a median time of 0733 h (range = 0542–0918 h). The median time of onset of activity in 27 follows of 17 different hyenas was 1834 h (range = 1443–2037 h). The majority of activity observed during daylight hours occurred during the first 2 h after sunrise (Fig. 2). Based on composite 24-h follows, in which all hours were sampled equally, hyenas spent 31.5% ± 2.7% of their time active. During hours of darkness (1900-0600 h) hyenas spent 53.0% ± 4.1% of their time active, and 96.2% ± 0.9% of all activity occurred from 1800 to 0900 h. Only 9.7% ± 1.2% of their active minutes occurred during daylight hours (0700–1800 h).

Fig. 2

Activity pattern and movement rates of radiocollared adult spotted hyenas (Crocuta crocuta) in the Masai Mara National Reserve, Kenya. Data are based on direct observations during long-term (2- to 15-h) follows of males and females. Number of individuals sampled varies per hour (n = 15–19). Plotted values for each hour (e.g., 1200 h) represent activity recorded in the following hour block (i.e., 1200–1259 h). The black bar extends over hour blocks characterized by darkness throughout the year.

Movement rates showed the same general pattern as activity (Fig. 2); onset and cessation of movement were closely associated with sunrise and sunset and the majority of daytime movement occurred in the early morning. Using only composite 24-h follows, the mean movement rate for the entire 24-h period was 584 ± 64 m/h (range = 147–1,185 m/h). Minimum nightly distance traveled based on follows > 8.5 h in length (X̄ = 11.4 h) averaged 12.4 ± 1.9 km (range = 3.5-21.7 km).

Duration of active bouts from 1800 to 0900 h averaged 62 ± 6.2 min, with 48% of active bouts being less than 30 min in duration (Fig. 3). There was much individual variation in the timing and length of bouts of activity, and in the total amount of time spent active (Fig. 3). Bouts of inactivity from 1800 to 0900 h averaged 53 ± 4.5 min in length. The longest recorded active bout during this period was for a male and lasted 383 min; the longest inactive bout was for a female and lasted 257 min.

Fig. 3

Bouts of activity during 14 composite 24-h follow cycles for 13 individual radiocollared spotted hyenas (Crocuta crocuta). Active bouts were >5 consecutive active minutes bounded on both ends by 5 consecutive minutes of inactivity. Pictured 24-h cycles were those for which the night was described by no more than 2 follow segments. The letter “a” indicates a pair of follow cycles conducted on the same individual. Start and end points of each follow segment are indicated by a –v.” For example, the topmost follow cycle is composed of 3 nonconsecutive follow segments conducted from 1730 to 0100 h, 0100 to 1000 h, and 1000 to 1730 h. Asterisks indicate hunts and fresh kills on which the focal hyena fed. Hours of darkness throughout the year fall within the shaded area.

Change in group size showed a bimodal pattern (Fig. 4). Not surprisingly, a similar pattern emerged from analysis of percent of time spent socializing, indicating that the majority of clan interactions occur either between 1900 and 2300 h or just after sunrise, between 0600 and 0700 h (Fig. 4). Whoop vocalizations were recorded from 1829 to 0706 h and were equally likely to occur during all 2-h blocks from 1800 to 0800 h (χ2 = 8.43, d.f. = 6, P = 0.209).

Fig. 4

Mean number of group-size changes observed and mean percent of time spent socializing during follows of radiocollared spotted hyenas (Crocuta crocuta). Data are from direct observations of 16 different individuals (11 females and 5 males) during 22 composite follows, each covering an entire 24-h period in nonconsecutive segments. Other notation is as in Fig. 2.

Sex differences.—Comparison of time budgets of males and females, based on composite 24-h follows, revealed several differences. On average, males (n = 5) spent more time traveling (U = 11.0, 1-tailed P = 0.031; Fig. 5). Males also spent more time hunting than did females (U = 6.0, P = 0.015; Fig. 5), but only 15 hunts were observed. Although focal females whooped during only 7 of 15 composite follows, focal males whooped during each of 7 composite follows. Mean whoop rates for the 11 females and 5 males were 0.04 and 0.34 times/h, respectively (U = 0.00, P = 0.002). Thus, males whooped 8.5 times more often than did females.

Fig. 5

Mean percent of time spent engaged in various behaviors for 5 male and 11 female spotted hyenas (Crocuta crocuta) during follows covering the entire 24-h period in nonconsecutive segments. Miscellaneous activity included standing, and sniffing objects or the ground. Traveling included both directed movement and wandering behavior. Significant differences (Mann-Whitney (U-test, P < 0.05) are indicated by an asterisk.

Although both sexes started activity at the same time of day, males tended to spend a larger portion of the 24-h period active (37.9% ± 5.7%) than did females (28.6% ± 2.7%; U = 16.00, 1-tailed P = 0.097; Fig. 6A; Table 1). The greatest sex differences in activity occurred in the morning time block (26.7% ± 10.1% and 11.0% ± 2.8%; U = 13.00, 1-tailed P = 0.071; Table 1). Males showed clear peaks in activity from 2200 to 2300 h, and from 0600 to 0700 h, during which activity levels averaged close to 80% (Fig. 6A), but comparable peaks in activity of females were not apparent.

View this table:
Table 1

Mean (SE) activity and movement rates for male (M) and female (F) spotted hyenas in the Masai Mara National Reserve, Kenya. Time periods are as follows: evening = 1400–1900 h; nightl = 1900–2300 h; night2 = 2300–0300 h; night3 = 0300–0700 h; morning = 0700–1100 h.

Mean % time activeMean movement rate (m/h)
Evening10.0 (4.0)8.0 (2.2)0.479166 (63)82 (25)0.139
Nightl62.3 (8.6)52.1 (7.0)0.2411,474 (255)1,014 (265)0.062
Night255.6 (7.7)44.6 (7.3)0.1711,540 (374)957 (292)0.238
Night359.4 (14.6)49.2 (8.4)0.2111,247 (380)1,193 (242)0.500
Morning26.7 (10.1)11.0 (2.8)0.071445 (124)307 (104)0.190
24-h dayb37.9 (5.7)28.6 (2.7)0.097737 (137)515 (64)0.063
  • a Based on results of 1-tailed Mann-Whitney U-tests.

  • b Based only on data from composite 24-h follow cycles.

Fig. 6

A) Sex differences in mean percent of time spent active by radiocollared adult spotted hyenas (Crocuta crocuta). Data are based on direct observation during long-term (2- to 15-h) follows of males and females. Number of individuals sampled varies per hour (females n = 9–11; males n = 5–8). Figure notation is as in Fig. 2. B) Mean hourly movement rates of radiocollared adult spotted hyenas excluding data collected during hour blocks when focal females nursed their young. Number of individuals sampled varies per hour (females n = 7–11; males n = 5–7).

Males tended to exhibit higher movement rates than did females over the 24-h period (U = 14.00, 1-tailed P = 0.063; Table 1) with the most obvious differences observed during the 1st half of the night (Fig. 6B). Movement rates of males peaked at 0000–0100 h, but movements of females did not show a clear peak (Fig. 6B). The maximum distance moved in a single hour was 4,680 m by a male hyena and 4,513 m by a female. All movement rate averages are likely underestimates because extremely fast movement sometimes resulted in termination of follows.

Effects of social rank.—Because we found differences among clans in some measures of activity (see below), we restricted our analysis of social rank to those measures of activity that showed no differences among the clans. We pooled females from both clans, resulting in use of 6 high-ranking (4 Talek and 2 Mara River) and 5 low-ranking (2 Talek and 3 Mara River) females. Based on composite 24-h follows, high-ranking females were no less active (26.7% ± 3.6%) than low-ranking females (30.9% ± 4.2%) over the 24-h period (U = 11.00, 1-tailed P = 0.233). In addition, high- and low-ranking females showed no differences in the percent of time spent resting, hunting, or traveling (U > 7.0, P > 0.14), and they showed similar movement rates during the 24-h period (U = 13.00, 1-tailed P = 0.358). However, females of lower rank spent more time feeding (2.2% ± 0.4%) than did those of high rank (0.8% ± 0.3%; U = 3.0, P = 0.028).

Differences among clans: ecology. —Monthly prey counts yielded estimates of prey density that did not differ significantly among the clans (Mara River = 196.6/km2, Talek West = 210.8/km2, Talek East = 181.9/km2; Kruskal-Wallis test: H = 2.17, d.f. = 2, 48, P = 0.124). The average size of lion groups seen within the territories of the 2 Talek clans ( = 3.9 ± 0.26) was no different than that of groups seen within the Mara River territory ( = 3.4 ± 0.30, U = 6,284.5, P = 0.108). In addition, 1–2% of observation sessions included lions, either alone or with hyenas, in both Mara River and Talek territories.

Illegal grazing of cattle, sheep, and goats inside the Reserve occurred nearly every day within the territories of both Talek East and West clans. Monthly livestock censuses recorded an average of 991 cattle and 1,038 sheep and goats utilizing the area within the Talek West territory, and 515 cattle and 257 sheep and goats within the Talek East territory. Livestock grazing in the Talek area, whether inside or outside the Reserve, typically occurred from 0900 to 1800 h. In contrast, no livestock were ever seen in the Mara River clan's territory. Tour vehicles were present in both territories primarily during only 2 periods each day: 0630–0900 h and 1630–1900 h.

During these periods, researchers observed tour vehicles 4.8 times more frequently while observing hyena groups in Talek than in the Mara River territory.

Differences among clans: activity and movement.—Because males and females were not sampled equally among clans, and because we demonstrated differences in activity and movement rates between the sexes, comparisons of activity and movement between the Talek West and Mara River clans include only data from females. Female hyenas from the Talek West clan were followed 30 times for 206 total hours ( = 6.9 h/segment) and Mara River females were followed 29 times for 176 h ( = 6.1 h/segment). Using composite 24-h follows, Mara River females (n = 5) were no more active (27.3% ± 4.0%) than were Talek West females (29.7% ± 3.9%, n = 6) over the 24-h period (U = 13.0, P = 0.715; Table 2). However, differences between clans were apparent in the timing of activity, with Mara River females showing more activity than Talek West females in the evening (1-tailed P = 0.025; Fig. 7A) and during daylight hours (1-tailed P = 0.034; Fig. 7A). In addition, the evening onset of socializing was delayed for Talek females relative to Mara River females (Fig. 7B). Although females from both clans showed an early evening peak in percent of time spent socializing, that peak occurred 3 h earlier in Mara River than in Talek (Fig. 7B). Comparisons of 24-h time budgets showed no differences between the 2 clans in percent of time spent engaged in any specific behaviors (U > 7.0, P > 0.17). Additionally, no differences were observed in overall movement rates or timing of movements during the 24-h period between females from the 2 clans (Table 2)

View this table:
Table 2

Mean (SE) activity and movement rates for female spotted hyenas from either the Talek West (TW) or Mara River (MR) clans within the Masai Mara National Reserve, Kenya. Time periods are as in Table 1 and daylight is 0700–1800 h.

Mean % time activeMean movement rate (m/h)
Evening13.1 (2.7)3.9 (1.7)0.025b115 (6)70 (33)0.350b
Nightl52.0 (12.0)52.2 (9.2)1.0001,026 (569)1,009 (339)1.000
Night236.5 (11.3)51.3 (9.5)0.361735 (100)1,068 (446)0.643
Night337.1 (7.4)59.4 (13.2)0.144993 (301)1,361 (377)0.361
Morning9.2 (4.8)12.2 (3.8)0.335b353 (277)292 (122)0.370b
Daylight012.3 (1.9)6.9 (1.9)0.034b128 (37)108 (45)0.357b
24-h dayc27.3 (4.0)29.7 (3.9)0.715463 (56)558 (109)0.465
  • a Based on results of Mann-Whitney U-tests.

  • b One-tailed P-values.

  • c Based only on data from composite 24-h follow cycles.

Fig. 7

The mean percent of time spent A) active and B) socializing by radiocollared adult female spotted hyenas (Crocuta crocuta) from 2 different social groups (clans). Data are based on direct observation during long-term (2- to 15-h) follows. Number of individuals sampled varies per hour (Talek West n = 5 or 6; Mara River n — 4 or 5 for activity and n = 3–5 for socializing). Figure notation is as in Fig. 2.

Differences among clans: communal den use.—We conducted 17 evening long-term observations at communal dens in Mara River and 28 in Talek. Den-dwelling young were 1 st seen at communal dens earlier in the evening and at a wider range of times in Mara River (median = 1716 h; range = 1540–1854 h) than in Talek (median = 1844 h, range = 1738—1906 h; P < 0.001). In addition, time of arrival at the communal den of either an adult female or large subadult was earlier and more variable in Mara River (median = 1654 h, range = 1323–1853 h) than in Talek (median = 1834 h, range = 1730—1908 h; P < 0.005).

We recorded 3,300 scans (morning: 1,353, evening: 1,947) at active communal dens in Talek East and West clans and 1,562 scans (morning: 759, evening: 803) in the Mara River clan. Logistic regression indicated that time had a significant influence on the probability of Talek hyenas being present at the communal den in both the morning (log-likelihood χ2 = 11.778, d.f. = 1, P< 0.001) and evening (log-likelihood χ2 = 53.022, d.f. = 1, P < 0.001) periods; scans were more likely to reveal no hyenas late in the morning and early in the evening (Fig. 8). In contrast, time did not influence hyena presence at communal dens during either the morning (log-likelihood χ2 = 1.130, d.f. = 1,P = 0.288) or evening (log-likelihood χ 2 = 0.704, d.f. = 1, P = 0.401) observation periods in the Mara River clan (Fig. 8). Therefore den use, as documented by both observation methods, appeared to begin later in the evening and end earlier in the morning in the Talek clans than in the Mara River clan, further reinforcing the apparent evening phase delay suggested by observed differences in the timing of activity and socializing.

Fig. 8

Percent of A) evening and B) morning scans at active communal dens in which no hyenas were present during each of 5 half-hour blocks for the Mara River Clan and the Talek East and West clans.


General activity.—Overall activity levels of Mara hyenas corresponded closely with those reported for C. crocuta in South Africa (Kalahari Gemsbok National Park: 31.0% of 24 h, 55.3% of nighttime—Mills 1990; Kruger National Park: 27.5% of 24 h—Henschel 1986). Mara hyenas also spent amounts of time resting (70.7%) and traveling (19.9%) that were similar to those reported for Kalahari C. crocuta (69% inactive, 23.6% foraging). However, Kalahari hyenas traveled more than twice as far each night ( = 27.1 km/night) than did Mara hyenas. This difference may reflect the much larger clan territories observed in the Kalahari ( = 1,095 km2), where prey densities are far lower than in Kenya (Mills 1990). The nightly distance traveled by Mara C. crocuta (X = 12.4 km) matched more closely that of a female followed in Ngorongoro National Park ( = 10.1 km—Kruuk 1972), where clan territories are more similar in size to those of Mara clans (Ngorongoro National Park: = 23.8 km2Honer et al. 2005).

As in previous studies, we observed onset of activity to occur around sunset, with the majority of daytime activity occurring early in the morning (Kruuk 1972; Mills 1990). Like Henschel (1986), but in contrast to Kruuk (1972), we found little evidence of consistent peaks in activity through the night, likely resulting from a large degree of individual and nightly variation in activity. However, peaks in socializing and group-size changes offer insight into the fission-fusion sociality of Crocuta. The majority of socializing within the clan, particularly by females, is conducted soon after onset of activity each evening. Groups formed during this period often remain relatively stable through the night until just after sunrise, when groups undergo additional reshuffling before the daytime rest period. We found the frequency of whooping activity to be constant throughout the night, as was also shown for males at dens in the Serengeti (East and Hofer 1991a).

Although graphs depicting an average activity pattern (as in Fig. 2) are useful for describing general patterns, they fail to depict episodes of rest that may occur frequently and unpredictably throughout the night. Our study reports the 1st records of duration of active and inactive bouts for this species and indicates a highly punctuated pattern of nightly activity, with frequent bouts of inactivity interspersed among active bouts of highly variable duration. Individual differences in the timing and length of active bouts were remarkable, as has been observed in other large carnivores (Garshelis and Pelton 1980; Theuerkauf et al. 2003b). However, occasional and unpredictable group behaviors such as border patrols, interactions between lions and hyenas, and interclan conflicts influenced timing and levels of nightly activity within individual follow segments, and replication within individuals would be necessary to adequately assess individual variation in activity. Previous studies of some felids have noted a detectable reduction in activity for multiple days after kill events (Puma concolorBeier et al. 1995; Lynx rufusSchmidt 1999). However, felids may take several hours or days to consume a carcass, whereas hyenas feed with remarkable speed (e.g., 18 kg food h−1 hyena−1Kruuk 1972) and commonly feed in groups, thus reducing the likelihood that single kill events would significantly influence patterns of activity.

Sex and rank differences.—Because follows were logistically difficult, many of our analyses suffer from small sample sizes and few replicates within individuals, so factors such as weather and prey abundance may have influenced individual activity and movement estimates. We attempted to follow individuals exclusively during clear weather, and across a wide range of conditions of prey abundance, but we were otherwise unable to control for these factors. Although previous studies have shown seasonal variation in movements of hyenas due to fluctuations in prey abundance (Hofer and East 1993; Trinkel et al. 2004), these studies were conducted in areas where prey abundance in some regions decreased annually to near-zero values, whereas the Reserve supports relatively stable resident populations of ungulates throughout the year. Furthermore, when pooling females from both study clans, we found no correlation between local prey densities and hyena movement rates or activity, and 2 females that were followed in both periods of high and low prey density showed very similar activity rates (J. M. Kolowski et al., in litt.). However, our sample sizes prevented us from specifically controlling for these factors and our results should therefore be interpreted with caution.

We predicted, based on sexual selection theory, that the significant positive relationship between reproductive success of males and time spent with receptive females (East et al. 2003; Szykman et al. 2001) would demand higher rates of movement and activity in males than in females. Indeed, like Henschel (1986), we found that male spotted hyenas tended to be more active and to travel further than females during a 24-h period. Here, differences were most pronounced in the hours just after sunrise and sunset.

The African lion displays fission-fusion sociality similar to that of spotted hyenas, with group composition being both temporary and unpredictable (Schaller 1972). Although male lions of unknown or nomadic social status have been shown to range more widely than resident females during the night (Hemson 2003; Stander 1997), comparisons between males and females of the same resident pride have not been performed. The fission-fusion society of C. crocuta is also remarkably similar in many respects to that of some primates, including spider monkeys (AtelesChapman 1990; Symington 1990) and chimpanzees (Pan troglodytesLehmann and Boesch 2004). Although chimpanzees generally show no sex differences in their time budgets, males travel faster and cover greater daily distances than do females (Doran 1997). In spider monkeys, the fact that males range more widely, travel faster, and spend more time traveling than females within the shared group territory has been suggested to be the result of males monitoring females and patrolling territory boundaries (Shimooka 2005). Because participation in territory defense and border patrolling behavior is no more common in male than female C. crocuta (Boydston et al. 2001), we believe the sex differences we observed reflect male monitoring of females rather than territory boundaries.

Although low-ranking female spotted hyenas range more widely than high-ranking females (Boydston et al. 2003a; Honer et al. 2005), we found no rank-related variation in movement rate or activity levels among the females followed here. We also found time budgets to be remarkably similar between high- and low-ranking females with the exception of more time spent feeding by low-ranking females. Although high-ranking hyenas spend more time feeding than low-ranking clan members in competitive feeding situations (Frank 1986), we suspect that low priority of access to kills forces low-ranking individuals to rely on lower-quality food (e.g., bone) and may force them to engage in longer, more frequent feeding bouts over time. One would similarly predict low-ranking females to hunt more often than high-ranking females, and although our sample size for hunts was too small to detect rank effects, previous research has demonstrated this trend (Holekamp et al. 1997b).

Clan differences.—Female hyenas in the Talek West Clan showed less daytime and early evening activity than did females in the Mara River Clan. In addition, the range of times utilized by Talek East and West females when attending the communal den was small relative to that of Mara River females, with den use by the Talek females starting later in the evening and ending earlier in the morning. Various ecological differences might potentially have caused the observed differences in use of time between study clans, yet the Talek and Mara River territories differed very little except with respect to the intense daily exposure of Talek hyenas to the presence of tour vehicles and livestock.

Examination of our data suggests that activity of tour vehicles alone could not account for observed differences between clans with respect to activity and den use of hyenas. Despite an often heavy volume of tour vehicles from 0630 to 0830 h, when hyenas are generally active but before cattle enter the Reserve, we found no reduction in activity or movements of Talek females relative to Mara River females during this period. Additionally, despite constant tourist presence in Talek from 0630 to 0900 h, den use by Talek hyenas progressively decreased as the start of the grazing period approached. During the evening onset of hyena activity, when both tourist use and livestock activity was high in Talek, activity of hyenas was reduced, and both den use and peaks in socializing were delayed relative to those observed among Mara River females. Tour vehicles, although abundant in both Talek clan territories, do not pose a direct threat to hyenas and have been present in this ecosystem for more than 3 decades. However, Maasai herdsmen represent a direct threat to hyenas, because humans are an important source of mortality for this population, 2nd only to lions (H. E. Watts, in litt.). Additionally, hyenas appear to perceive herdsmen as a threat because hyenas often flee from guarded cattle herds, whereas cattle left unattended by herders are not avoided (J. M. Kolowski et al., in litt.). This response also has been noted among African wild dogs (Fuller and Kat 1990). Taken together, these observations suggest that cattle grazing, but not tourism, affected temporal distribution of activity among Talek hyenas.

Although the influence of human disturbance in the form of livestock grazing on the activity patterns of other carnivore species has not been investigated, activity shifts similar to those observed here have been described in response to a wide variety of anthropogenic disturbances with predictable temporal schedules. Carnivores that typically show some degree of diurnal activity have been found to increase or completely rely upon nocturnal activity when faced with the threat of hunting mortality (Andelt 1985; Kitchen et al. 2000) or harassment resulting from human recreational activities (Beckmann and Berger 2003; Olson et al. 1998), except where spatiotemporal avoidance is possible (Theuerkauf et al. 2003a). Similarly, daytime movements and activity have been reduced or eliminated among carnivores living in urban, or human-dominated landscapes (Ciucci et al. 1997; Lucherini et al. 1995; McClennen et al. 2001; Riley et al. 2003).

Although direct fitness costs might be expected to result from reduced diurnality in species adapted for daytime or crepuscular activity (e.g., cheetah, bears, and coyotes), such direct costs are not expected in hyenas. Their night vision is believed to be as good as their day vision (Kruuk 1972), and variation in hunting success with time of day has not been reported. However, there may be indirect fitness costs in this species when daytime activity is eliminated. For example, diurnal activity may reduce risk of predation on hyena young by lions, which are active almost exclusively at night (Schaller 1972; Stander 1992). Similarly, little daytime activity by predators was suggested to explain diurnal activity exhibited by female wolves with young in an otherwise nocturnal group (Vilà et al. 1995). In addition, a reduction in the range of times available to females to nurse young at dens could potentially reduce overall numbers of nursing bouts, increase energetic stress on both young and mothers, and promote social conflict over access to dens. Although we did not observe enough nursing bouts or lion-hyena interactions in the 3 clans to address these hypotheses, examination of long-term demographic data indicates no recent reductions in survival of young or clan size in the Talek area (H. E. Watts, in litt.), suggesting that these indirect costs, although potentially important, have not reduced fitness in these hyenas.

We have shown that human disturbance can alter patterns of activity and den use in this species. Although it remains unclear what fitness costs might ultimately be incurred by spotted hyenas from disturbance-based alteration of normal activity patterns, documentation of behavioral changes such as these among large carnivores is critical to the development of our understanding of human-carnivore interactions and the extent to which carnivores can adapt to human presence. Changes in activity patterns or movements can potentially be used as early behavioral indicators of the extent and severity of human disturbance and may have other unforeseen consequences. For example, reduction of daytime activity by large carnivores might negatively influence monitoring efforts based on sighting data (Caro et al. 1998), or reduce the frequency with which tourists can observe these animals.


The research presented here was described in Animal Research Protocol 05/05-064-00, approved most recently on 3 April 2006 by the All University Committee on Animal Use and Care at Michigan State University. The work was supported by National Science Foundation grants IBN0113170, IBN0343381, and IOB0618022 to KEH and by grants from the Graduate School at Michigan State University to JMK. We thank the Office of the President of Kenya for allowing us to conduct this research. We also thank the Kenya Wildlife Service, the Narok County Council, and the Senior Warden of the Masai Mara National Reserve for their cooperation and assistance. Hyena follows would not have possible without the efforts and motivation of S. A. Wahaj and M. A. Gibbons. C. Beaudoin, S. M. Dloniak, I. Graham, K. M. Kapheim, J. E. Smith, and J. B. Tanner also participated in field data collection and L. Kierepka and K. Lawracy provided helpful assistance with certain analyses. We are grateful to L. Smale, who provided valuable comments and suggestions throughout the preparation of this manuscript. Finally, we thank the staff and management of Mara Intrepids Lodge for their support, logistical and otherwise, without which this study would not have been possible.


  • Associate Editor was Rodrigo A. Medellín.

Literature Cited

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