Readings in mammalogy : selected from the original literature and introduced with comments
27-28 -H 1 1—1 1  5 6 7258 5 6 (J(J9 (f 9tf(JiJ 6 i <S 99i39 i (f FEB 28- , M^ /—' rV r-^-V ' ■ ■ I ' I " V- "*'''^" ' B BBS RM M MRMM M M MMM M M MMMMMR MM 2577 35 5 57118 5 857752 7 5 9(J 9 9(S(J(J (J 9 999 tf 9 (59 9(J9 9(5 MARCH -r'-' H IT-' 1 '-'— 1 rn- '-2 MR BB B M RRM MM MR R M MM M MMM MRH R 73 5 335577347 77 8 5772 52 9^ cr (5(5(5 i59 9(5(5 9 9 9 9^9 99(5 9 6 7 8 9 10 II NOON I 23456789 10 II NIOHT 1 2 3 4 5 6 Fig. 2. — A sample record of the total traffic in a single runway over a period of six days. Marks above the base Hnes indicate passages from right to left, and marks below the base line passages from left to right. R represents Reithrodontomtjs; M, Microtus; B, bird ( includes brown towhee, wren-tit, and song sparrow); and RAB, brush rabbit. Most of the mice are further identified by number and sex. 354 176 JOURNAL OF MAMMALOGY Vol. 40, No. 2 a 4-month-old male Microtus and a 5-month-old male Reithrodontomys ap- peared in the same photograph. The history of one runway indicates that traffic by Reithrodontomys alone does not keep a Microtus runway open. One or more Microtus passed almost daily along this runway during February. At the end of the month the Microtus disappeared and two Reithrodontomys became active in the same runway. Despite an average of 3.3 passages per day by Reithrodontomys throughout March and up to mid-April, grass and weed seedlings grew up 3,0 >- O z UJ §5 - MEADOW MICE ALL MONTHS N = 6077 - UJ U. 6 7 8 9 10 II 12 I NOON 234567 89 lO II 12 I 23456 NIGHT Sic >- o z UJ cr u. HARVEST MICE ALL MONTHS N = 1753 6 7 8 9 10 II 12 I 2 3 4 5 6 7 8 9 10 II 12 I NOON NIGHT 2 3 4 5 6 20 > o I 10 o or BRUSH RABBIT N= 94 m 6 7 8 9 10 II 12 I 2 3 4 5 6 7 8 9 10 II 12 I NOON NIGHT 2 3 4 5 6 Fig. 3. — Distribution by hours of 6,077 passages of meadow mice (above); 1,753 passages of harvest mice (center); and 94 passages of brush rabbits (below). 355 May, 1959 PEARSON— TRAFFIC SURVEY 177 in the runway and it began to look unused. By the end of April almost all traffic had ceased. The Reithrodontomys data will be analyzed in a later report. Birds. — Of the 382 bird records, at least 255 were of sparrows ( at least 122 song sparrow; the remainder mostly fox sparrow, white-crowned sparrow and ■golden-crowned sparrow ) . Other birds recognized were wren-tit, wren, brown towhee and thrush. On several occasions birds, especially song sparrows, battled their reflections in the window of the instrument shelter. This caused long series of exposures. Each series was counted as a single passage. If the bird stopped for a minute or more and then returned to the battle, this was counted as another passage. All bird records were during daylight hours. On three occasions a sparrow and an adult Microtus appeared in the same photograph. On one of these occurrences a song sparrow was battling its reflection when an adult, lactating Microtus came along the runway. The sparrow retreated about 12 inches toward the camera shelter and, as soon as the mouse had passed, returned to the runway. Brush rabbit. — All except four of the records of brush rabbits were in June and July of 1957, a season when these animals, especially young ones, were abundant. Figure 3 (below) shows that they were most active in the early morning. -^20- o ^ 10 ■=> a tu CL jh 30 >20 o z UJ 3 S 10 cr 6 8 10 12 2 4 6 NOON 8 10 12 2 4 NIGHT JFMAMJJASOND Fig. 4. — Distribution by hours of 56 passages of shrews (left) and distribution by months of 56 passages of shrews (right). Shrew. — The dry, weedy habitat chosen was not favorable for shrews, and they were near the minimum weight necessary to depress the treadle of one of the recorders, so that some may have passed along the runway without making a record. The shrews were highly nocturnal (Fig. 4, left) and avoided the surface runways during the dry summer months (Fig. 4, right). Since captive specimens of Sorex are rarely inactive for more than one hour ( Morrison, Amer. Midi. Nat., 57: 493, 1957), the scarcity of records in the daytime probably means only that the shrews were not moving above ground at this time. They may have been foraging along gopher, mole and Microtus tunnels during the daytime. 356 178 JOURNAL OF MAMMALOGY Vol. 40, No. 2 A shrew was marked on March 4, a few inches from one of the recorders. It was captured 15 feet away on May 30 and 5 feet farther away on June 23. It passed along the study runway five times in the 16-week interval between first and last capture: on March 13, 27, 31, and April 17, and possibly on April 10 (markings obscured). Another shrew was recorded on March 27. Unless baited traps attract shrews from a considerable distance, or the recorder repels them, a trapper setting traps in this runway for a few nights would have had small chance of recording the presence of this individual which apparently was nearby for at least 16 weeks. Not a single shrew was recorded during the dry summer months of June, July and August. Nevertheless, on July 8 when I was checking the photo- electric recorder at 5:55 am, a shrew emerged completely from a small hole in 100 90 80 70 60 1 50 Q i X UJ 40 > UJ a: 30 20 10 • : SHREWS O = LIZARDS 50 60 TEMPERATURE CF) Fig. 5. — A comparison of the temperatures and humidities encountered by shrews and fence Hzards in tlie runways. The larger circles show the position of the mean for each species. The large polygon encloses the range of temperatures and humidities available to the animals during the study. 357 May, 1959 PEARSON— TRAFFIC SURVEY 179 the ground a few inches from the instrument shelter, twitched his nose rapidly for a few seconds, and retreated down the same hole. The air temperature was 54° and the relative humidity 78 per cent — normal for this season. Obviously shrews were present on the study area during some or all of the summer months but were not frequenting the surface runways. Figure 5 shows the temperatures and relative humidities encountered above ground by the shrews on the study area compared with the total range of temperatures and humidities recorded throughout the study. By their nocturnal, winter-time activity shrews encountered the coldest, most humid conditions available in the region. In contrast, the similarly small, insectivorous fence lizards existing in the same habitat managed by their own behavioral patterns to encounter a totally different climate (Fig. 5). The mean of the temperatures recorded at the times of lizard passages was 39° warmer than that recorded for shrew passages, and relative humidity was 36 per cent lower. This activity pattern of shrews differs from that reported by Clothier (Jour. Mamm., 36: 214-226, 1955) for Sorex vagrans in Montana. He found shrews there to be active "both day and night and throughout the year, even during extremely bad weather." It is important to understand, however, that he collected in damp areas near water, where the shrews may not have had to modify their activity to avoid desiccation. Extremely bad weather, for a shrew, is hot dry weather. Peromyscus. — Peromyscus truei was abundant in brushy places and in houses nearby; P. maniculatus was scarce. Some of the Peromyscus records were clearly of truei and some may have been of maniculatus, but many could not be identified with certainty. No adult P. californicus was recognized although a few young ones may have passed and been listed as truei. All passages of Peromyscus were at night. Salamander. — The record includes passages by both Etisatirui escholtzii and Aneides luguhris. They were recorded in October, November, March and April. By being nocturnal and by avoiding the dry season, they encountered in these autumn and spring months about the same microclimate as shrews, but were recorded neither in the winter months nor at temperatures below 39°. A third species, Batrachoccps attenuatus, was common in the study area but is so small that it could not be expected to actuate either of the recorders. One Batrachoccps electrocuted itself underneath the treadle but has not been included in the records. Comparison of traps and recorders. — The combination of live-trapping and photographing revealed a failure of small mammals to move between runways only a few feet apart. On several occasions meadow mice and harvest mice were live-trapped a few feet from one of the recorders, were released at the same place, and were recaptured a week or more later not more than a few feet away, yet during the intervening time they failed to pass the recorder. Conversely, some individual mice repeatedly recorded themselves on the films yet could never be induced to enter any of a large number of live traps placed 358 180 JOURNAL OF MAMMALOGY Vol. 40, No. 2 in the same runway and in nearby runways. It is obvious that all mice present do not use all of the active runways close to their home, and it is also obvious that neither the recorders nor traps give a complete accounting of the mice present. SUMMARY A motion-picture camera synchronized to an electronic flash unit was used to record the passage of animals along meadow-mouse runways and to record the temperature, relative humidity and time at which they passed. More than 26 species used the runways during 111 weeks of recording. Meadow mice, harvest mice, sparrows, brush rabbits and shrews passed most frequently. The average traffic per day in each runway was 11 passages; on some days there were more than 60 passages. Rarely more than ten meadow mice or six harvest mice used a runway in any one period. Meadow mice and harvest mice used the same runways simultaneously. Traffic by harvest mice alone did not keep the run- ways open. Meadow mice were active during the day and night; harvest mice were strongly nocturnal. Brush rabbits were active primarily early in the morning. Almost all shrews were recorded at night and in the winter months. Consequently, they encountered the coldest, most humid conditions available to them. In contrast, the similarly small, insectivorous fence lizards encountered a microclimate that was 39° warmer and 36 per cent less humid. Neither traps nor recorders accounted for all the individuals living nearby. Museum of Vertebrate Zoology, Berkeley, California. Received October 29, 1957. 359 PREY SELECTION AND HUNTING BEHAVIOR OF THE AFRICAN WILD DOG' RICHARD D. ESTES, Division of Biological Sciences, Cornell University, Ithaca, Nevv York JOHN GODDARD, Game Biologist, Ngorongoro Conservation Area, Tanzania Abstract: African wild dog (Lijcaon picttis) predation was observed in Ngorongoro Crater, Tanzania, between September, 1964, and July, 1965, when packs were in residence. The original pack of 21 dogs remained only 4 months, but 7 and then 6 members of the group reappeared in the Crater at irregular intervals. The ratio of males: females was disproportionately high, and the single bitch in the small pack had a litter of 9 in which there was only one female. The pack functions primarily as a hunting unit, cooperating closely in kilhng and mutual defense, subordinating individual to group activity, with strong discipline during the chase and unusually amicable relations between members. A regular leader se- lected and ran down the prey, but there was no other sign of a rank hierarchy. Fights are very rare. A Greeting ceremony based on infantile begging functions to promote pack harmony, and appeasement behavior substitutes for aggression when dogs are competing over meat. Wild dogs hunt primarily by sight and by daylight. The pack often approaches herds of prey within several hundred yards, but the particular quarry is selected only after the chase begins. They do not run in relays as commonly sup- posed. The leader can overtake the fleetest game usually within 2 miles. While the others lag behind, one or two dogs maintain intervals of 100 yards or more behind the leader, in positions to intercept the quarry if it circles or begins to dodge. As soon as small prey is caught, the pack pulls it apart; large game is worried from the rear until it falls from exhaustion and shock. Of 50 kills observed, Thomson's gazelles (Gazella thomsonii) made up 54 percent, newborn and juvenile wildebeest {Connochaetes taiirmus) 36 percent. Grant's gazelles (Gazella granti) 8 percent, and kongoni (Alcelaphus buselaphus cokei) 2 percent. The dogs hunted regularly in early morning and late afternoon, with a success rate per chase of over 85 percent and a mean time of only 25 minutes between starting an activity cycle to capturing prey. Both large and small packs generally killed in each hunting cycle, so large packs make more efficient use of their prey resource. A minimum of 4-6 dogs is needed to function effectively as a pack. It is concluded that the wild dog is not the most wantonly destructive and disruptive African predator, that it is an interesting, valuable species now possibly endangered, and should be strictly protected, particularly where the small and medium-sized antelopes have increased at an alarming rate. The habits of the African wild dog or Cape hunting dog (Lijcaon pictus) have been described, sometimes luridly, in most books about African wildlife. Accounts by such famous hunters and naturalists as Selous (1881), Vaughan-Kirby (1899), and Percival (1924), repeated and embellished by other authors, have created the popular image of a wanton killer, more destructive and disruptive to game than any other African predator. ^ Field work supported by the National Geo- graphic Society; also by grants from the New York Explorers Club and the Tanzania Ministry of Agriculture, Forests and Wild Life. 52 Because of its bad reputation, the wild dog was relentlessly destroyed in African parks and game reserves for many years. In Kruger National Park, for instance, it was shot on sight from early in the present century up until 1930 as part of an overall policy to keep predators down. In Rhode- sia's Wankie National Park some 300 wild dogs were killed by gun and poison be- tween 1930 and 1958. Acceptance of modem concepts of wild- life management has finally brought an end to the indiscriminate destruction of wild dogs and other predators in most, if not all, African national parks. There is now 360 The African Wild Dog • Estes and Goddard 53 a general awareness among game wardens in sanctuaries, paid very little attention to of the predator's role in regulating popula- cars and could be watched undisturbed tions, which perhaps began with Stevenson- from within 30 yards or less. It was also Hamilton ( 1947 ) , Warden of Kruger Park feasible to keep pace with the pack during for almost 30 years, who related the alarm- chases over the central Crater floor, either ing increase of impala {Aepijceros me- driving parallel to the leader at a distance lampus) to the disappearance of the park's of 100-200 yards or following behind and formerly large wild dog packs. to one side so as not to get in the way of While the wild dog has benefited from other pack members. To locate the pack more enlightened concepts of game man- initially, we often drove to an observation agement, its reputation, still based on pop- point on a hill and scanned the Crater with ular writings and myth, remains unchanged, binoculars and a 20-power binocular tele- I But recent scientific investigations indicate scope. When the pack was moving it could that a new and less-prejudiced evaluation often be spotted at a distance of over 5 of this species is long overdue. Kiihme miles, and a number of chases and kills ( 1965 ) has studied the social behavior and were clearly observed from a hilltop family life at the den of a pack with young through the telescope. whelps on the Serengeti Plains, Tanzania. We have observed prey selection and hunt- RESULTS ing behavior in a free-ranging pack of _ , _ J ,^ J . 1 • V XT Pack Composition adults and juveniles m nearby Ngorongoro ^ Crater, a caldera with a floor area of 104 The pack that first entered Ngorongoro square miles that supports a resident pop- Crater in September, 1964, contained 21 ulation of around 25,000 common plains animals, including 8 adult males, 4 adult herbivores. The two studies together throw females, and 9 juveniles. They remained quite a different light on the habits, char- more or less continually in residence through acter, and predator-prey relationships of December, then disappeared and were pre- this highly interesting species. sumed to have left the Crater. One juvenile We are indebted to Dr. B. Foster of the female had died of unknown causes. Dur- Royal College, Nairobi, and to G. C. ing January, 1965, seven members of the Roberts of the Crater Lodge for reporting same pack, 4 males, 1 female, and 2 juvenile four kills and one kill respectively, that males, reappeared; after a lapse of 5 they witnessed in the Crater; also to Pro- months, apparently the same animals, minus fessors W. C. Dilger, O. H. Hewitt, and one male, again took up residence, and H. E. Evans of Cornell University for criti- have been observed off and on up to the cal readings of the manuscript. Nomencla- present writing. In March, 1966, the female ture follows Haltenorth (1963) for artio- whelped but died 5 weeks later, leaving dactyls, and Mackworth-Praed and Grant 8 male and 1 female pups. They were (1957) for birds. brought up by the 5 males, who fed them by regurgitation until they were old enough MtTHODS j-Q j.yj^ \Ni\h the pack. However, the female Most observations were made from a and 4 male pups died, leaving an all-male vehicle; we each had a Land Rover and pack of 9 in August, 1966. usually operated independently. The wild While an all-male pack must be excep- dogs, like many other African predators tional, there is other evidence to suggest 361 54 Journal of Wildlife Management, Vol. 31, No. 1, January 1967 that a high proportion of males may be observed sexual behavior on only two oc- common in this species. The pack Kiihme casions, when one male mounted another studied consisted of 6 adult males and 2 repeatedly as the latter was feeding at a adult females, which had 11 and 4 pups kill. Kiihme also saw very little sexual be- respectively, sex unreported. During 2-3 havior. When two animals were competing years of shooting in Kruger National Park, for the same piece of meat, each would try the ratio of males was 6 : 4, despite an to burrow beneath the other, its forequarters attempt to select females (Stevenson-Hamil- and head flat to the ground and hind- ton 1947). We have no explanation to offer quarters raised, tail arched and sometimes for the discrepancy, but if it is real and wagging. The ears were flattened to the not normal, it might help explain the head and the lips drawn back in a "grin," reported decline of wild dogs during recent while each gave excited twittering calls. As years in many parts of Africa. Kiihme observed (p. 516), the dogs "tried to outdo each other in submissiveness." Social Organization In this way juveniles and even subadults Leadership and Rank Hierarchy. — In the manage to monopolize kills in competition full pack of 21 and in the pack of 7, the with adults. The young thus enjoy a priv- same adult male was consistently the ileged position in the pack. Pups at the leader; he usually led the pack on the hunt, den successfully solicit any adult to regur- selected the prey, and ran it down. In the gitate food by poking their noses into the pack of 6, from which the above male was corner of the adult's mouth, sometimes lick- absent, the adult female was the leader, ing and even biting at the lips. Since all One of the males filled the position after pack members contribute to feeding and her death. protection of the young, the mother is not Apart from the position of leader, we saw essential to their survival after the first few no indication of a rank order. eluded there was no hierarchy in the pack Greeting Ceremony. — Whenever the pack he observed, nor even a leader. The equality became active after a rest period, and of pack members may partly explain the particularly if two parts of the pack were singularly amicable relations typical of the reunited after being separated, the mem- species. On the other hand, competition for bers engaged in a Greeting ceremony ( Fig. food and females could easily lead to ag- 1), in which face-licking and poking the gression; yet neither Kiihme nor we ever nose into the corner of the mouth played a saw a fight. prominent part. The ceremony thus ap- Food Solicitation and Appeasement Be- f)ears to be ritualized food solicitation; the havior. — Overt aggression and fighting are fact that Kiihme actually saw regurgitation minimized through ritualized appeasement elicited by begging adults supports this in- behavior derived from infantile food beg- terpretation. The Greeting ceremony in ging. Begging and appeasement appear in the wolf (Canis lupus), in which one takes almost every contact between individuals, another's face in its jaws, may have the and particularly in situations where aggres- same derivation. sion would be most likely to occur — for As a prelude to greeting, dogs typically instance, when animals are competing over adopted the Stalking attitude (Fig. 2), with a kill. However, we cannot comment on the head and neck held horizontally, shoul- sexual competition, having seen none; we ders and back hunched, and the tail usually 362 The African Wild Dog • Estes and Goddard 55 Fig. 1. Greeting ceremony. hanging. Kiihme (p. 512) interprets this posture as inhibited aggression; the same attitude is adopted when approaching po- tential prey and competitors of other species. The Stalking posture changed to greeting when dogs got close. In greeting- solicitation, as they licked each other's lips and poked the nose into the corner of the mouth, one or both crouched low, with head, rump, and tail raised stiffly ( Fig. 1 ). Except for the raised head, this resembles the submissive posture displayed when two dogs are competing over food. The Greet- ing ceremony was also frequently per- formed while two dogs trotted or ran side by side. Vocal Communication. — Although Perci- val (1924), Stevenson-Hamilton (1947), Ma- berly (1962), Kiihme (1965), and others have given good descriptions of wild dog calls, the function of the calls has often been misinterpreted. This applies partic- ularly to two of the three most frequently heard calls (Nos. 1 and 3): 1. Contact call — a repeated, bell-like "hoo." Often called the Hunting call, it has nothing to do with hunting as such, but is given only when members of a pack are separated. Though a soft and musical sound, it carries well for 2 or more miles. When members of the Ngorongoro pack- were missing, an imitation of the Contact call would bring the rest to their feet, whereas there was at best onlv a mild reac- Fig. 2. The Stalking attitude, here displayed by the pack leader while approaching a herd of gazelles. tion to imitations when the full pack was assembled. 2. Alarm hark — a deep, gruff bark, often combined with growling, given when star- tled or frightened. A good imitation near a resting pack elicited an immediate star- tled reaction. 3. Twittering — a high-pitched, birdlike twitter or chatter. The most characteristic and unusual vocalization, it expresses a high level of excitement. It is given in the prelude to the hunt, while making a kill, in mobbing hyenas or a pack member, and by dogs competing over food. Its primary function is evidently to stimulate and con- cert pack action. Kiihme described this call (Schnattern) only in the context of the Greeting ceremony (p. 513). Besides these vocalizations, whining may be heard during appeasement behavior and when pups are begging, and members of the pack sometimes yelp like hounds when close on the heels of their prey. Kiihme (p. 500) further distinguishes an Enticing call (Locken) given by adults calling the young out of the den, and a Lamenting call (Klage) given by pups when deserted. Olfactory and Visual Communication. — Wild dogs hunt primarily by sight and by daylight. We never saw them track prey by scent. Though they evidently have a good nose and may well use it for tracking in bush country, olfaction in this species seems to have a primarily intraspecific significance. 363 ^cn 56 Journal of Wildlife Management, Vol. 31, No. 1, January 1967 \^ regular hunting cycle is the likeUest ex- planation; it was more usual, however, for the pack then to wait until the following regular period. Wild dogs will also hunt on moonlight nights, as Stevenson-Hamilton noted. When the Crater dogs had not killed before dusk, the hunt was sometimes pro- longed. The latest kill we recorded was at 7:32 PM, when it was fully dark. Since they are capable of functioning as a pack and of hunting successfully after dark, the fact that wild dogs are so strongly diurnal may seem puzzling. But it may be Fig. 3. Time distribution of 50 wild dog kills. explained by the fact that they hunt mainly 1 1 CO CO _j 1 1 ^ _i U- o L o 1 ■ .0. 1 I ■ Ji J 6 li- 7'8 ' 12 ' 1 ' 2 ' 3 ' 4 5 PM^ TIME by sight; it would be much more difficult Wild dogs are renowned for their peculiarly to locate prey and single out a quarry at strong, and to many humans disgusting, night. As to the regularity and brevity of odor, which may emanate from anal glands their hunting cycles in early morning and but seems to come from the whole body, late afternoon, this is partly a measure of Sniffing under the tail, responsive urination their hunting efficiency, discussed below, and defecation are socially important activ- Also, of course, these are the times in the ities. But the main role of the strong body day when diurnal animals, particularly odor may be to permit high-speed tracking herbivores, are most active and most ap- of the pack by members that have lost proachable. visual contact. Lagging members seen run- Apart from a certain amount of play and ning on the track taken by the rest of the other social activities shortly before starting pack sometimes appeared to be using their to hunt and immediately after feeding, noses. Similarly, the white tail tip probably pack members were usually active only helps maintain visual contact in bush coun- while actually hunting. At other times they try, high grass, and under crepuscular con- could often be found resting near or in the ditions; in a species notable for every pos- same place where they had settled after the sible color variation, a white-tipped tail is morning or evening kill. When resting, the most constant and conspicuous mark. pack members customarily lay touching in close groups (Fig. 4). Generally speaking, Daily Activity Pattern ^^xe pack became active between 5:30 and The Ngorongoro pack had two well-de- 6:15 pm, and in the morning within Mj fined hunting periods each day (Fig. 3). hour of dawn, remaining active for 1-2 That this periodicity is characteristic of the hoiu-s. But where game is less plentiful species may be inferred from Kiihme's ob- than it is in Ngorongoro, and a pack must servations (p. 511), and from Stevenson- range more widely (Stevenson-Hamilton Hamilton's (1947) observations in Kruger gives a range of at least 1,500 square miles National Park. In nine recorded instances, for a Transvaal pack whose movements though, the Ngorongoro dogs killed between were reported over a period of years ) , a 8:30 AM and 3:30 pm, well outside the nor- good deal of time between and during mal periods. Failure to kill during the hunts must be spent in travel. 364 The African Wild Dog • Estes and Goddard 57 Fig. 4. Part of a resting pack, lying typically close together. Hunting Behavior Prelude to the Hunt. — Periods of activity were initiated by the actions of one or a few dogs apparently more restless than the others; rarely did the whole pack arise spontaneously at the start of an activity- cycle. Typically, one dog would get up and run to a nearby group, nose the others and tumble among them until they re- sponded. Within a few minutes the whole pack would usually become active. But if, as sometimes happened, the majority failed to respond to the urging of a few, then all would settle down to rest again. Sometimes, after a brief bout of general activity, the whole pack would lie down once more, even if it was past the usual time of hunt- ing. During the first 5 or 10 minutes after rousing, the pack members sniffed, urinated, defecated, greeted, and romped together. Play and chasing tended to become pro- gressively wilder and reached a climax when the whole pack milled together in a circle and gave the twittering call in unison. As soon as this melee broke up, the pack usually set off on the hunt. Kiihme (p. 522) interprets this performance (specifically the Greeting ceremony) as "a daily re- peated final rehearsal for the behavior at the kill," wherein mutual dependence and friendliness are reinforced by symbolic beg- ging, thus enabling the dogs to share the kill amicably, ^^'hile this may be one func- tion, the progressive buildup of excitement before hunting looked to us like nothing so much as a "pep rally," that served to bring the whole pack to hunting pitch. The be- havior of domestic dogs urging one another to set off on a chase is somewhat similar. The Mobbing Response. — During the mill- ing preparatory to hunting, we sometimes saw what appeared to be incipient mob- bing action toward a pack member, when up to half a dozen dogs would gang up on one, tumble and roll it but without actually biting it. Intensive play between two or three animals usually preceded and seemed to trigger a mobbing reaction in other mem- bers, who signaled their intentions by ap- proaching in the Stalking posture. Percival (1924:48) reports seeing a pack mob and kill a wild dog he had wounded. The oc- currence of "play" mobbing suggests that it could indeed become serious when an animal is maimed. On the other hand, sick and crippled pack members are often not molested: one very sick-looking old male in the large pack trailed behind the others for over a month before recovering, and though he kept usually a little apart, was tolerated at kills. It is significant that basically the same mobbing behavior, at high intensity, is dis- played when wild dogs kill large prey and when they harass spotted hyenas, their most serious competitor. It seems very likely, in fact, that mobbing is an innate re- sponse which governs pack action in hunt- ing, killing, and mutual defense. It is per- haps the key to pack behavior in all animals that display it. That mobbing appears in 365 58 Journal of Wildlife Management, Vol. 31, No. 1, January 1967 play and can be released by a conspecific more than 300 yards was generally not which is wounded or otherwise transformed pursued. As far as we could tell, the prey from its normal self, supports the hypothesis animal was never singled out until after that it is an innate response. It is also note- the pack, or at any rate the leader(s), had worthy that a wild dog removed from its broken into a run. pack apparently makes little effort to defend In the pack of 21, juveniles and some itself against attack. Selous ( in Bryden adults usually lagged far behind, and often 1936:24) reported that a wild dog caught caught up 5-10 minutes after the kill was by a pack of hounds shammed death and made. In the small pack, however, corn- then escaped when he was about to skin it. monly all kept together and spread out on Hunting Technique. — Sometimes the pack a front during the stalking phase. When all would set off on the hunt at a run and started running on a front, sometimes more chase the first suitable prey that was than one dog picked out a quarry from the sighted. More often, there was an inter- fleeing herd, whereupon the pack might val of 10-20 minutes during which the dogs split, some following one dog, the rest trotted along, played together, and engaged another. Kiihme ( p. 527 ) considered this in individual exploratory activity, stopping the normal pattern and noted that often to sniff at a hole or a tuft of grass, then each animal acted for itself in selecting a running to catch up with the rest. At this quarry before all combined on a common stage, when the hunt had started but before goal. In this way the slowest prey tended any common objective had been deter- to be selected. Selection by this method mined, individuals might forage for them- was exceptional for the Ngorongoro pack, selves. The observer would suddenly notice which had a definite leader; as a rule the that a dog was carrying part of a gazelle lead dog made the choice and the rest of fawn or a young hare (Lepus capensis), the pack fell in behind him. Nor did it that must have been simply grabbed as it appear that any effort was made to single lay in concealment. Once during a moon- out the slowest prey, although that would light hunt by a small pack that visited the be difficult to observe clearly. Crater in 1963, individual dogs were seen Again as a general rule, no attempt was to pick up at least two gazelle fawns and made to carry out a concealed stalk, which one springhare {Pedetes surdaster), a would in any case be practically impossible strictly nocturnal rodent, within V2 hour, by daylight on the short-grass steppe. But Concealed small game such as this is ap- on one occasion the pack of six made use parently not hunted by the pack in concert, of a tall stand of grass to get near a group Preparatory to the chase, there was fre- of Thomson's gazelles. On another hunt the quently a preliminary stalking phase dur- pack apparently took advantage of a slight ing which the pack approached herds of elevation in the expectation of surprising game at a deliberate walk, in the Stalking any game that might be out of sight on the attitude (Fig. 2). The dogs appeared to be far side. They moved deliberately up the attempting to get as close as possible with- slope, then broke into a run and swept at out alarming the game, and certainly the full speed over the crest on a broad front flight distances were much less than when —but without finding any quarry that time, the pack appeared running. The chase was When the leader had selected one of a launched the moment the game broke into fleeing herd, he immediately set out to run flight. But game that began running at it down, usually backed up by one or two 366 The African Wild Dog • Estes and Goddard 59 other adults who maintained intervals of 100 yards or more behind him, but might be left much further behind in a long chase. The rest of the pack lagged up to a mile in the rear. Discipline during the chase was so remarkable among all pack members that even gazelles which bounded right be- tween them and the quarry were generally ignored. The average chase lasted 3-5 minutes and covered 1-2 miles. At top speed a wild dog can perhaps exceed 35 mph, and can sustain a pace of about 30 mph for several miles. Once when a chase had begun but no single quarry had yet been selected, a male in the pack of 21 broke away and proceeded to make a 5- mile circular sweep quite by itself, turning on bursts of speed when gazelles bounded off before him, but without ever singling one out. His average speed, as determined by pacing him in a vehicle, was approxi- mately 20 mph. In descriptions of wild dog hunting methods, much has been made of their intelligent cooperation in "cutting comers" on their prey, and particularly of their relay running, with fresh dogs taking the place of tired leaders. We concur that there is a basis for the first idea, but we saw no evi- dence whatever to support the contention that wild dogs run in relays. The truth is that wild dogs have no need to hunt in relays. The lead dog has ample endurance, if not the speed, to overtake probably any antelope, of which gazelles are among the fleetest. The fact that other members of the pack are able to cut comers on the prey is at least partly accounted for by the prey's tendency to circle instead of fleeing in a straight line. As explained later, some prey animals have a greater tendency than others of their species to do this. Of course, once overtaken, even a quarry that has been running straight is forced to start dodging if it is to avoid being caught straightaway. Thus a dog running not too far behind the leader is well placed to cut corners when the quarry changes course, and it frequently happened that one of the followers made the capture. Most game, after a hard chase of a mile or two, was too exhausted by the time it began dodging to have any real chance of evading its pursuers. Killing and Eating. — Wild dogs killed small game hke Thomson's gazelles with amazing dispatch. Once overtaken, a gazelle was either thrown to the ground or simply bowled over, whereupon all nearby dogs fell on it instantly. Grabbing it from all sides and pulling against one another so strongly that the body was suspended between them, they then literally tore it apart ( Fig. 5 ) . It happened so quickly that it was never possible to come up to a kill before the prey had been dismembered. If it didn't go down at once, dogs began tear- ing out chunks while it was still struggling on its feet. We once saw a three-quarter term fetus torn from a Thomson's gazelle within seconds of the time it was overtaken and before it went down. As Kiihme ob- served, there is no specific killing bite as in felids (Leyhausen 1965). When dealing with larger prey such as juvenile wildebeest and notably a female kongoni, the dogs slashed and tore at the hind legs, flanks, and belly — always from the rear and never from in front — until the animal fell from sheer exhaustion and shock. They then very often began eating it ahve while it was still sitting up (Fig. 6). Self-defense on the part of a prey was never once observed; the kongoni, for example, did little more than stand with head high while the dogs cut it to ribbons, looking less the victim than the witness of its own execution. In eating, the dogs began in the stomach cavity, after first opening up the belly, and proceeded from inside out. Entrance was 367 60 Journal of Wildlife Management, Vol. 31, No. 1, January 1967 Fig. 5. The pack tearing apart a young gnu calf. also effected through the anus by animals unable to win a place in the stomach cavity. While several dogs forced their heads in- side and ripped out the internal organs, others quickly enlarged the opening in struggling for position. This resulted in skinning out the carcass, leaving the skin still attached to the head, which was sel- dom touched. Apart from these, the back- bone and the leg bones, very little of a Thomson's gazelle would remain at the end of 10 minutes. In the pack of 21, if only part had managed to eat their fill, sometimes the rest went off to hunt again before the carcass was cleaned. They pro- ceeded to chase and pull down another gazelle within as little as 5 minutes from the time of the previous kill, to be joined shortly by the other dogs. As each animal became satisfied it withdrew a little from the kill and joined others to rest, play, or gnaw at a bone it had taken along. Some- times the pack stayed at the scene until the next hunting period; more often it with- drew to a nearby stream or waterhole and settled down there. Kiihme never saw wild dogs drink. The Ngorongoro pack drank, though irregularly, before hunting and after eating. Selection of Prey and Frequency of Kills Table 1 summarizes prey selection by species, sex, and age in 50 recorded kills. The 11 wildebeest calves were all taken in January during the peak calving season, when the pack of seven dogs apparently specialized on them; only kills of calves were seen by us or reported by Crater visi- tors in this month. Thus the percentage of calves in the total gives a biased picture of prey selection during the rest of the year. With new calves excluded, the adjusted percentages, based on 39 kills, are as fol- lows: Thomson's gazelles 69 percent Juvenile wildebeest 18 percent Grant's gazelles 10 percent Kongoni one kill Wright (1960:9) records a similar pre- ponderance of Thomson's gazelles in 10 Fig. 6. Dogs begin eating a yearling-class gnu while it is still alive, but evidently in a state of deep shock. 368 The African Wild Dog • Estes and Goddard 61 Table 1. Prey selection by species, sex, and age in 50 kills of the African wild dog. Prey Species Total No. Adult Males Adclt Females JUVENILE- SUBADULT Young* Percent of Total Kills Thomson's gazelle 27 18 6 2 1 54 Wildebeest 18 0 0 7 11 36 Grant's gazelle 4 1 1 2 0 8 Kongoni 1 0 1 0 0 2 * Less than 6 months old. kills on the Serengeti Plains (7 Thomson's gazelles, 1 wildebeest, 1 impala, and 1 reed- buck [Redunca redwica]), and notes that it is the staple diet of wild dogs in the Serengeti. Kiihme also observed that wild dogs prey mainly on Gazella thomsonii and G. granti, and young wildebeest in the Serengeti. In terms of actual preference, informa- tion from the Serengeti, where the Thom- son's gazelle is by far the most numerous herbivore, is far less revealing than the fig- ures from the Crater, where this species oc- curs in relatively small numbers. The status of the principal ungulates in Ngorongoro, based on an aerial count by Turner and Watson ( 1964 ) , on two ground counts of the gazelles by the authors in collaboration with the Mweka College of Wildlife Man- agement, and on our ground counts of the less numerous species, is as follows: Wildebeest 14,000 Zebra 5,000 Thomson's gazelle 3,500 Grant's gazelle 1,500 Eland {Taurotragus oryx) 350 Waterbuck {Kobus defassa) 150 Kongoni 100 Reedbuck 100 (?) The evidence suggests, then, that Thom- son's gazelle is the preferred prey of the wild dog in East African steppe-savanna. In the miambo woodland (Brown 1965) that extends from mid-Tanzania into South Africa, where gazelles are not found, the main prey may be impala, followed by other medium- to small-sized antelopes and the young of large antelopes. In Kruger Park, for example, of 88 identified wild dog kills, 85 percent were impala (Bourliere 1963). Stevenson-Hamilton Hsted other prey as reedbuck, bushbuck ( Tragelaphus scrip- tiis), duiker (Sijlvicapra grimmia and Cephal- ophus spp.), and steinbok (Raphicerus campestris), also female waterbuck and kudu {Tragelaphus strepsiceros) when pressed by hunger. In Wankie Park, war- dens' reports indicate a considerable toll of young kudu, eland, sable (Hippotragus niger), and tsessebe (Damaliscus lunatus). Instances where adult female and even adult male kudu were pulled down by wild dogs are also cited. Bourliere states (1963:21) that "Carnivores actually only prey upon herbivores of about the same size and weight." While this gen- eralization is open to dispute, it applies well enough to East African wild dogs preying on Thomson's gazelles. Where the main prey is impala, reedbuck, etc. that weigh in the 100-150 lb class, weight and size may be double or triple that of the wild dog. But the wild dogs of the East African steppe-savanna are smaller (also darker, with more black and less tan and white) than their counterparts in Central and South African woodland (Fig. 7). The average weight of the animals we have seen in East Africa would not exceed 40 lb; the members of a pack seen in Wankie Park, by comparison, looked to be a good 3 inches taller and 20 lb heavier. This consistent geographic size variation may be adapted to size of the principal prey species; specifi- 369 62 Journal of Wildlife Management, Vol. 31, No. 1, January 1967 Fig. 7. Two specimens of the larger, lighter-colored wild dog of southern Africa, photographed in Wankie National Park. cally, wild dogs of the East African plains may be smaller as the result of specializa- tion on Thomson's gazelle. 