Waterbuck (Kobus Defassa) Daily Activity Pattern

Naturalistic Observation

Preliminary Study



Five Waterbuck (Kobus Defassa) of a seven member herd’s daily activity pattern was observed in a naturalistic environment during the course of forty three consecutive days in five minutes intervals in Baobab Farm Game Reserve. The regular activity pattern was discovered in case of place utilization, body posture, and movement and feeding activity. Random distribution of behavior elements was found in secretion and various activities of social behavior. There was no significant difference in movement and feeding among the individual animals except for a juvenile bull that had longer periods of resting and a pregnant female occupied while feeding. There were significant differences in social behavior categories depending on gender and age.



I conducted this observation as a volunteer at Bamburi Quarry Nature Trail Game Sanctuary in 1991-92.

Bamburi Quarry Nature Trail is a successful environmental experience where Dr Rene Haller Swiss biologist assisted by (among others) lead biologist Sabine Baer revitalized an abandoned limestone mine and created a self-cleaning water cycle system, in which they circled the water between crocodile and tilapia farm through rice paddies and Nile Cabbage (Pistia Stratiotes).

“Dames” (Conocarpus lancifolius), from Somalia, the “coconut palm” (Cocos nuciferc) and the “whistling pine” (Casuarina equisetifolia) from Australia were the first plants – after experimenting with 26 species – that was able to stick and slowly tame the soilless ground. With the help of a little centipede (Epibolus pulchripes), the birds and other animals followed the barren landscape once it became a paradise.

After the successful revitalization, the Park established a Snake exhibition and Game Sanctuary.

In the Game Sanctuary’s 72,000 m2, there were two rescued hippopotamuses, two giraffes, a zebra, five eland, two oryx and a herd of waterbuck: There was one adult male, 4 adult females and two youngsters, a male and a female, living together. While I was there, two buffalo joined the game park.

The night guard discovered that the little waterbuck herd occasionally leaves the enclosure by jumping over the electric fence. We wondered what the reason was for those night adventures..

Before I could answer that question, I started to map their daily activity within the enclosure.



Chronobiology is the branch of biology that studies annual, seasonal, tidal and diurnal rhythmical features of different kind of organisms at the psychological, molecular and behavioral level.

Daily rhythmical changes in activity are called circadian rhythms. It is regulated by Suprachiasmatic Nucleus; a small region of the brain in the hypothalamus. It synchronizes with environmental cues like light or social interaction.

Most experiments regarding circadian rhythms were conducted in the laboratory where light and other variables were closely monitored and tightly controlled.

In the case of most species, naturalistic observation of daily activity patterns show regular cycles in certain elements of animal behavior. Black rhinoceros, warthog and sitatunga all had two activity peaks in the early morning and before sunset. (E. Joubert and F.C. Eloff 1971, H.I.V.D.Kiwia 1986, G Clough 1970, Rosemary E.A. Owen 1970,)

Two inactivity peaks: “not feeding after dark before dawn” was observed in case of waterbuck, (C.A.Spinage 1968) different, but regular pattern in activity in case of zebra. (E. Joubert 1972.)

Black rhinoceros and impala were inactive during the middle of the day. (M.V. Jarman and P. J. Jarman 1973.) The latter one most probably “entrained” by the heat of the day.



Watebuck: Kobus defassa (Class: Mammalia, Order: Artiodactyla, Family: Bovidae, Genus: Kobus, Species: Kobus Defassa)

Waterbuck is a middle sized robust antelope with a shaggy brown coat with double white patch on their buttocks. Their secretion glands emit smelly, oily fluid that keeps their coat waterproof.

Their height at shoulder is 122-137 cm. Males are about 0.25% larger than the females.

 Only the males have heavily ringed, curved horns. They range from 40-60 cm long. They are water dependent, (C. R. Taylor, C. A. Spinage, C. P. Lyman: 1969.) and are distributed in savanna grasslands, gallery forests and riverine woodlands of East and South Africa.

Waterbucks are mixed feeders, mostly grazing on long grass. Furthermore, they are ruminant in that they rechew the cud to further break down plant matter to stimulate digestion. . 

The males establish territory at about 5-6 years of age. Its size ranges from 0.1square km to 2 square km, and own it until they are 8 to9 years old.

The females move in groups with calves on bigger home ranges that could overlap more males’ territory. (C. A. Spinage: 1969/a.)

Females seek isolation one or two days before parturition. In the first two-four weeks, the calves stay hidden. The dam visits them only one or two times a day for suckling which takes about five minutes. Meanwhile the mother licks the calf to eliminate any odor that might attract predators. 

At about four weeks the calves follow their mother. The weaning occurs at 6-8 months of age. At that time, calves graze as much as the adults. (C. A. Spinage, 1969/b.)

Until establishing their own territory, the young males join bachelor herds. Typically, the females stay in the mother’s group. The associations between group members are occasional.  Individual recognition is made by the combination of sound, scent and sight. (C.A. Spinage 1982)

This particular herd of waterbuck consisted of an adult male, four adult females, (one of them was pregnant and gave birth in February 1992.) one female and one juvenile male about half a year old.



The home of the big games, including the waterbuck herd, is the Wildlife Sanctuary. It is an integral part of the Bamburi Quarry Nature Trail. It is placed in Kenya, 12 km north to Mombasa, Kenya.

The Game Sanctuary consists of 72,000 m2, roughly oval shaped area surrounded by electric fence.

At the time of this observation, the inhabitants were two hippopotamus, two oryxes, five eland, two giraffe, two buffaloes, seven waterbuck and a big flock of ibis and two fish eagle. The giraffes and buffaloes came into the enclosed area only during the daytime and they were herded to their night time enclosure or “boma” for the night.

The area was divided into three parts: the first part of it was covered by Casuarina forest, another third was a grass field, and there was a little lake with an island in the middle of the third area.

The weather is tropical. Humidity is close to 100% constantly. The average temperature in the day time is 36 degrees Celsius, in the night time 27 degrees Celsius. There are two rainy seasons in October and in March. During the observation from the 13th of December 1991 to 28th of January 1992, there was a dry season.  There was only one day where there was a short rain falling.


After a short habituation period, I followed the animals from a relatively short distance, and recorded their behavior and listed them in the categories below. Originally I tallied their behavior in one minute intervals using coding sheets. Time was represented in the horizontal axis and the behavior elements on the vertical axis. At the data analysis phase, I realized that this amount of data is way too difficult to handle and it does not provide extra information. At this phase, I re-coded the sheets. In case of behavior elements measured by duration, I counted the behavior when it happened longer than three minutes within the five minutes interval. In case of the behavior elements that were measured by frequency, I counted the behavior element if it happened within the five minute interval.

            Data collection occurred in the daylight hours from 6:30am to 6:30pm.

I coded 5 individual animals’ behavior; each one of them more than 10 different times (11 to 14) from each hour of the observation for forty three consecutive days. The five animals were:

Adult male

Three adult female (one of them pregnant)

Juvenile male




I divided the enclosure arbitrarily in eight areas: Bush West, Bush East, Plain West, Plain East, Lakeshore West, Lakeshore East, Feeding Place and Island. The proportions of these areas  roughly consisted of Bush West 4, Bush East 4, Plain East 4, Plain West 4, Lakeshore West 1, Lakeshore East 1, Feeding Place 1 Island 1. I recorded the duration of the time spent in particular areas. (See map.)





Sitting with closed eyes,


Measured: duration



Walk, – Measured: duration




Measured: frequency



Graze (feeding on grass),

Browse (Feeding on leafs, buds),

Eat dried grass; eat “Dairy cubes” (It was served at 4pm daily)

Ruminate (mouth movement without food intake)

Measure: duration

Drink, (Water from the Lake)


Measured: frequency





Measured: frequency



Scanning the environment (listening to a fix point)

Measured: frequency



Grooming, (scratch their fur/skin with their teeth)

Fawn on branches (rub head or horns on branches)

Measured: frequency



Allogrooming, (grooming one another)

Bother, (touching with nose lightly)

Aggressive bothering (poke with nose or intensely display toward directed motion)

Bother up (when the touching ends with the other animal change from sitting to standing/walking/running)

Chase (run after an escaping animal)

Suck (fawn nurse from mother)

Suckling (mother nurse fawn)

Try to suck (fawn put its head to mothers side before its hind leg)

Smelling bottom

Flehmen (special smelling with open upper airways)

Try to mount (short mounting movement without coitus)

Measured: frequency



Data analysis was made by Excel 5.0 (diagrams), SPSS paired sample t-test (duration measurements) SPSS Wilcoxon test (frequency measurements).





The vast majority of time the herd moved together.

Diagram 1 shows the places where the antelopes spent their time during different parts of the day. Time is in the horizontal axis broken down in half hour intervals. The percentage of the time they spent in a particular place is in the vertical axis.

In the early morning hours, I regularly found the herd in the west side of the bush sitting. Before noon they came out and spent about two hours walking and grazing through Field West, then Field East. The hottest hours from noon to 4pm they spent in Bush East. At 4 pm the Park Person brought dried grass and Dairy Cubes to the Feeding Place. The waterbucks alternately spent time in Feeding Place, and surrounding area: Field East, Field West and Lakeshore. During the observation period, they swam over to the Island only twice.

Diagram 1.



Diagram 2 and Diagram 3

As body posture and moving are closely connected, it is reasonable to discuss them together.

Most typical body posture and movement for the waterbucks were sitting or standing. Distribution of those shows a regular pattern: Sitting in the morning, walking through (grazing, see below) through Field West, Field East, sitting into Bush East during siesta time, walking out from the bush at 4pm at the feeding time to the end of the observation period at 6:30pm.

Changing in between activities: morning sitting to stand up and walking, sitting down at siesta time occurred within a half an hour time range.

Peaks in walking: around 7:30am and 11am in the morning, 4-5pm in the evening.

Peaks in sitting: around 8:30am a short sitting period, between, noon and 3:30 a longer “siesta”.

Occasionally they swam, jumped or ran; most likely in the most active part of the day, from 4pm to 6:30pm.

Lying with head down and sitting with closed eyes occurred only for very short periods of times.

Diagram 2.

Diagram 3.


Diagram 4

Feeding behavior also shows a regular pattern and it is also connected to the body posture and the movement. That is not only true for the feeding time, when the waterbucks appeared at the feeding place, but they maintained a regular pattern of grazing in the morning, then came a short period of ruminating. Before noon, they spent about two hours grazing while they were walking through Field West and Field East. Three peaks of grazing at 7am, 10am and 4:30pm.  From noon to 4pm, they sat in Bush East where they were ruminating again. Two peaks of rumination occurred at 9:30am and 1pm. From 4pm they were feeding on Dairy Cubes and dried grass that t the Park Person provided in the Feeding Place.

This alternating feeding behavior was in synchrony with the body posture and the movement: sitting with ruminating, grazing with standing and walking.

Grazing peak occurred at 7:30am, 10am and 5pm.

A short rumination peak was in the morning at 9:30am, a longer rumination bout happened between the 12pm-4pm “siesta”.

Diagram 4.


Diagram 5

Urination and defecation shows a fairly accidental pattern excluding an elevated frequency for the period around feeding time.

Diagram 5.


Diagram 6-11.

Most of the elements of the social behavior were rather random. However, in general, there were higher frequencies in the active evening hours around and after feeding time when the animals gathered around the Feeding Place.

Diagram 6.

Diagram 7.

Diagram 8.

Diagram 9.


Diagram 10.


Diagram 11.




In general, the herd moved together and spent the same amount of time in different places, except for the Feeding Place. There was a significant difference between the pregnant female and the juvenile bull. There was a trend difference between the adult and the juvenile bull: the juvenile spent the least amount of time in the Feeding Place. (Levels of significance: See Table 1.) Meanwhile there was no significant difference between the individual animals in spending time with eating at the Feeding Place.

Average time the individual antelopes spent at the Feeding place compare to all other places:

Adult male: 12%, Juvenile Male: 7%, Pregnant Female: 17%, Female 1: 12% Female 2: 9%.



Lying with the head on the ground and sitting with closed eyes happened very rarely and for short periods of times. However, it was worth noticing that this was the only body posture in which the members of the herd differed significantly. The juvenile bull laid down or sat with closed eyes longer than any other adult in the group. (Levels of significance: see Table 2. and Table 3.) It might be in accordance with young animal’s maturation period and more resting/sleeping time that is required.



Female two walked less than adult bull (p<0.005) and pregnant female (p<0.045).

 The juvenile bull was the only one that jumped during the observation period.



Combined Categories: I added the time of grazing, browsing and feeding on grass and Dairy Cubes. The two bulls spent less time with feeding, and the pregnant female spent less time than one of the other females. (Levels of significance: see Table 4.)


Browsing seldom occurred. In the cases where it did, juvenile male and the two females browsed more.

Grazing: pregnant female and one female grazed more than adult male.

Ruminating: pregnant female ruminated more than adult male. The juvenile male ruminated the least amount of time.

Eating dried grass: Juvenile male ate less than the adults.

There was no significant difference between the times spent eating Dairy Cubes.

(Levels of significance: see Table 5 – 8.)



The majority of differences among the individuals occurred in the elements of social behavior.

In Combined categories of social behavior elements, the adult bull applied the greatest quantity of social behavior.

(Levels of significance: see Table 9.)

There are some gender related behaviors among the elements.

Touch: The adult male touched the others more frequently than all other group members. Juvenile male also touched the others on more occasions than the females, but that level of significance is less strong as the in case of adult male.

Botherup: Adult male bothered up the other herd members more frequently than any other group members.

Fawned to fellows: adult and juvenile male rubbed its horns or head to the others more frequently, but they differed from each other as well: juvenile made it more often.

Smell bottom: adult male characteristic with strong significance.

 Flehmen: only adult male did.

Try to mount: Both male made it but the frequency of these latter two behavior elements is so low, that its frequency did not differ from the females 0 frequency significantly.

Allogrooming: Adult male showed the highest frequency in allogrooming.

(Levels of significance: see table 10 – 14.)

Bother away: there is an order between the five antelopes I observed in regards of how often they bother away the others. This order is: Adult male, Female one, Female two, Juvenile male, Pregnant Female. (Levels of significance: see Table 15.)

Chasing is the only category that showed female dominance. (Levels of significance: Table 16.)

Fawn on branch is the juvenile male exclusive category. (Levels of significance: see Table 17.)



The waterbuck herd had regular daily activity pattern in which place usage, movement and feeding activity was in close connection.

At about 6 am they were sitting and ruminating, at around 8 they took about a half an hour walk inside the bush while they were eating the fallen leaves of Casuarina trees. This bout of activity was relatively short and the start time varied within a half an hour range. Therefore, the curve of heightened activity in the categories is only slightly noticeable.

After this short feeding period, they found an area within Bush West were they were sitting and ruminating. Somewhere between 10am and 10:30am, they rose up again and walked through the Field West toward the Field East grazing. Again the curve in Field West and East does not separate sharply as the movement from West to East was slow and continuous. The start time of the activity varied within about half an hour.

At around noon during the hottest hours, they found shade in Bush East where most of the time they spent their siesta time alternately resting and ruminating.

At 4pm many animals gathered in the Feeding Place and the surrounding area: – Field East, Lakeshore East – including the waterbuck herd. This was the time of heightened activity, less regulated, more disturbed by their own herd members and other animals. In the vast majority, the competitive actions like chasing and bothering happened around this time. When other animals occupied the small feeding area, the waterbuck were sitting or standing nearby until they were having a chance to have a turn.

Mostly they drank from the lake between 4pm and 6:30pm when they gathered around the Feeding Place. Being that there was a couple of mud puddles within the enclosure. They occasionally they drank from those at different times during the day.

The only difference that occurred in the herd members regarding place utilization was the duration of being in the Feeding Place. However, they did not differ in time spent actively feeding. The order might reflect on the rank order, but was also influenced by necessity. The adult bull spent the most time there, pregnant female was second, the other two females followed, while the juvenile bull was there for the least amount of time.

Note that the time they spent with feeding did not differ. On the contrary, the time they spent on the feeding place did. Possibly the individuals with more access to the feeding place had a chance to take their time and feed and were less likely to rush than the individuals who had a chance to spend less time at the Feeding Place.

In general: the adult bull spent less time with the different elements of feeding activity. The pregnant female and one of the other females spent more time with grazing and the pregnant female spent more time ruminating which is in accordance with C.A. Spinage findings (1968).

The juvenile bull browsed more than the others and he was the one who occasionally was nursed too.

The only difference among the individuals regarding body posture was that the juvenile bull spent more time laying and sitting with closed eyes than the adults. Maturation processes might be in the background.

Although the Wilcoxon test did not show significant differences in grooming behavior between the members of the herd, the t-test did between the male and two adult females. Unfortunately, the t-test is not an accepted procedure for this comparison, but at least it can give us a sign value that something less expressed but similar difference occurred in case of waterbucks like M.S. Mooring and B.L. Hart observed in case of impala. (1995)

At this altitude, the waterbuck does not have a separate breeding season. In our case, due to lack  of a competitor and possibly because of living in an enclosed area, this adult bull did not show special territorial behavior like in the study of Mooring and Hart. However, the impala did.


However, the bull’s higher frequency of “bother up” and “smell bottom” can be interpreted as part of the behavior complex called “controlling females”. Another bull biased elements like “touch other” and “Allogrooming” can belong either in the “controlling females” complex, or can be interpreted as the bull’s more social behavior.

The juvenile bull on the other hand was higher than females, lower than adult male frequency of “touch other” and “smell bottom” which might be interpreted by the gender related social behavior complex under development.

The juvenile male had the highest frequency of “fawn to fellow” and his exclusive activity was “fawn to branches”. The latter one probably triggered by his growing horns.



Most of the time feeding related activity change was initiated by the pregnant female. She was the first standing up and started grazing on Field East in the morning or arriving to the Feeding Place in the afternoon.

I observed during the long siesta hours that a rumination bout lasted about 15-25 minutes, followed by a 30-45 minutes resting period without any activity. It seemed that the juveniles had shorter and more frequent bouts than the adults. The way how I collected and analyzed my data did not provide the opportunity to prove my observation.



Dr Haller’s request was finding answers whether or not the waterbuck herd leaves the enclosed area at night and if yes how often, as the night guard reported in some occasion. Further inquiry would have been to find out why. With lack of tools and for safety reasons, I was able to collect data with fewer details, without night vision from outside the fence.

After sunset their activity remained variable and was influenced by the many other species’ activity around them. Later in the evening they typically sat down at Lake East, where they hardly ever spent time in the daytime, maybe a little around feeding time. They spent about three  hours resting – probably ruminating occasionally, the mouth movement cannot be seen from the fence in the dark.

After these few hours they were headed to the bush where I haven’t followed them during the night. In morning I always found them in Bush East.

During this observation period, the herd did not leave the enclosure.



In Bamburi Quarry Nature Trail Game Sanctuary there were thirteen representatives of five mammal species living together in a 72,000 m2 area near the studied seven member herd of waterbuck. On the contrary of many other animal presents, the waterbuck herd had a well regulated, predictable daily activity pattern, in which moving-feeding and resting-ruminating periods alternated. The regular pattern was only disorganized by the closeness and the competition of others and each other at the Feeding Place at feeding time at 4 pm, when the care takers provided dried grass and Dairy Cubes.

In non-social behavior, the individual herd members did not differ from each other significantly excluding the juvenile bull spent more time in deep relax laying and sitting with closed eyes, and the pregnant female spent more time with certain element of feeding activity.

In social behavior there were some sharp as well as a few light differences among individuals that depended mostly on gender, age and pregnancy.



I am infinitely grateful for the Baobab Farm for the opportunity to conduct my observation in their Game Sanctuary. Special thanks to Dr Rene Haller and Sabine Baer for their support. I am grateful for the Scientific Academy of Hungary and the Teleki Sámuel Foundation for their help with the travel expenses.

I couldn’t be anywhere without the statistical work of Ákos Fekete and the computer work, advice and support of László Mérő.

I am thankful for Ádám Miklósi, Topál József, Tamás Székely and László Szemethy for their invaluable feedback and inspiration.




Table 1. Place utilization – Spending time in Feeding Place
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male   p<0.062      
Juvenile male          
Pregnant female   p<0.004      
Female 1          
Female 2          


Table 2. Laying
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male   p<0.016      
Juvenile male          
Pregnant female   p<0.000      
Female 1   p<0.003      
Female 2   p<0.000      


Table 3. Sitting with closed eyes
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male   p<0.016      
Juvenile male          
Pregnant female   p<0.05      
Female 1   p<0.009      
Female 2   p<0.005      


Table 4. Feeding – Combined categories
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male          
Juvenile male          
Pregnant female p<0.000 p<0.000   p<0.009  
Female 1   p<0.005      
Female 2 p<0.028 p<0.001      
Table 5. Browsing
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male          
Juvenile male p<0.02   p<0.006    
Pregnant female          
Female 1          
Female 2     p<0.025    


Table 6. Grazing
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male          
Juvenile male          
Pregnant female p<0.039        
Female 1 p<0.042        
Female 2          


Table 7. Ruminating
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male          
Juvenile male          
Pregnant female p<0.028 p<0.001      
Female 1   p<0.031      
Female 2   p<0.057      


Table 8. Eating dried grass
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male          
Juvenile male          
Pregnant female   p<0.003      
Female 1          
Female 2   p<0.006      


Table 9. Social behavior – combined categories
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male   p<0.005 p<0.000 p<0.003 p<0.004
Juvenile male          
Pregnant female          
Female 1          
Female 2          


Table 10. Touch other
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male   p<0.000 p<0.000 p<0.000 p<0.000
Juvenile male     p<0.036 p<0.02 p<0.03
Pregnant female          
Female 1          
Female 2          


Table11. Bother up
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male   p<0.002 p<0.028 p<0.002 p<0.002
Juvenile male          
Pregnant female          
Female 1          
Female 2          


Table 12. Fawn to fellow
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male     p<0.002 p<0.002 p<0.013
Juvenile male p<0.037   p<0.0001 p<0.000 p<0.000
Pregnant female          
Female 1          
Female 2          


Table 13. Smell bottom
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male   p<0.000 p<0.000 p<0.000  
Juvenile male          
Pregnant female          
Female 1          
Female 2          


Table 14. Allogrooming
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male     p<0.028 p<0.01 p<0.03
Juvenile male          
Pregnant female          
Female 1          
Female 2          


Table 15. Bother away
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male   p<0.007 p<0.000    
Juvenile male          
Pregnant female          
Female 1     p<0.05    
Female 2     p<0.021    


Table 16. Chasing
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male          
Juvenile male          
Pregnant female p<0,017        
Female 1 p<0.032        
Female 2          


Table 17. Fawn on branch
  Adult male Juvenile male Pregnant female Female 1 Female 2
Adult male          
Juvenile male p<0.000   p<0.000 p<0.000 p<0.000
Pregnant female          
Female 1          
Female 2          



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