BREEDING 195

before. She apparently gave birth on this occasion after a gestation period calculated at 71 days although on day 72, when she emerged showing no signs of pregnancy and no further interest in the nestbox, careful examination of the nestbox cage revealed no signs of parturi- tion or cubs. It seems probable that the young were stillborn and consumed directly by the mother who appeared in no way distressed and immediately resumed her normal daily routine.

From 16-22 May, ten days after the assumed parturition date, the 9 was once again in oestrus and mating was seen to take place on each of the last four days. Six weeks later the 9’s abdomen was again noticeably rounded and, 72 days after the last observed copulation, she gave birth successfully to two cubs which, a t the time of writing, appear to be doing well (Plate 1).

ACKNOWLEDGEMENTS The authors would like to thank Wendy Paterson for reviewing the paper and researching some of the infor-

mation included. Thanks are also due to Roger Edwards for providing the information on the photoperiod in the species’ natural habitat, and Lutz Kuschinski, Curator, for his observations on mating taken on 4 March 1981.

PRODUCTS MENTIONED IN T H E TEXT Abidec: aqueous multivitamin solution, manufactured by Parke-Davis, Pontypool, Gwent, Wales, Great Britain. Vita-E tablets: vitamin E tablets (one tablet, 200 i.u.), manufactured by Bioglan Laboratories Ltd, Letchworth, Great Britain. Mazuri: carnivore dietary supplement, manufactured by Special Diets Services Ltd, Stepfield, Witham, Essex, Great Britain.

REFERENCES ANDF,RSON, D. (1977): Gestation period of Geoffroy’s cat Leopardus geof ioy bred at Memphis Zoo. Inr. Zoo Yb. 17: 164-166. scmr. P P. (1970): Cats. In Reprodairion and breeding techniques in laboratory animals: 192-208. Hafez, E. S . E. (Ed.). Philadelphia: Lea and Tebiger.

Manuscript submitted 2 July 1982; revised August 1983

Breeding history of the Dorcas gazelles

a t the National Zoological Park, 1 96 1-1 98 1 Cazella dorcas

KARL R . KRANZI, WILLIAM A. XANTEN, JR2 & SUSAN LUMPKIN’ I Department of Zoological Research and 2Department of Mammalogy, National Zoological Park, Smithsonian hstitution, Washington, DC 20008, USA

The Dorcas gazelle Gazella dorcas is the most widely distributed of the African gazelles, its range covering the whole of North Africa and the Middle East (Gentry, 1971). Of the per- haps nine subspecies three, G. d. rnassaesyla, C. d. saudiya and G. d. pelzelni, are listed as Endangered in the IUCN Red data book and all are reduced in their range as a result of over- hunting and habitat deterioration because of overgrazing by domestic livestock. As part of the measures for the protection of these sub- species captive propagation programmes have been recommended with subsequent reintro- duction to suitable habitats (IUCN, 1972).

The Dorcas gazelle is a small antelope,

weighing c. 15 kg, with pale fawn colouring and no sharply contrasting markings. There is little sexual dimorphism apart from dd being larger than 9 9 and having longer, heavier and more strongly curved horns. The species occurs in semi-desert to desert habitats, pre- ferring open and flat terrain to hilly areas. Its colouring blends well with the surroundings and its physiology is adapted for water conservation in a number of ways (Cloudsley- Thompson & Ghobrial, 1965). The species feeds on a variety of desert vegetation, especially Acacia trees and succulents with a high water content; in some areas Acacia leaves serve as the sole source of both food and water.

196 BREEDING

In times of prolonged drought Dorcas gazelles may migrate long distances in search of water and nutritious vegetation. They are active mainly in the early morning, early evening and at night, spending the warmest part of the day resting in shallow depressions which they make by scraping the ground with their hooves. The social structure is similar to that of other Antilopinae (Essghaier, 1981) in that single adult dd maintain territories through- out the year, using dung piles as the principal means of marking the boundaries. Associated with the territorial dd are small herds of from three to 40 individuals consisting of adult Q Q, young and perhaps ‘bachelor’ dd.

HISTORY AND EXHIBITS The Washington National Zoological Park has maintained a herd of Dorcas gazelles, probably G. d. massaesyla, since 1960 when the first pair was received after it had been presented to President Eisenhower as a gift from the Presi- dent of Tunisia. Both animals (‘Granny’ and ‘Pappy’) were estimated to be between 12 and 18 months old on arrival; their first calf was born in May 1961. By 1972 the herd had grown to 15 animals, housed in two groups; all were descended from the original pair, the 0 of which (Granny) was still alive. Five additional gazelles born in the group had been sent to other zoos. Unrelated animals were brought into the herd after three of Pappy’s sons sired 19 calves by closely related Q Q , of which 14 died soon after birth. ‘Detroit’, (obtained from Detroit Zoo) was introduced into the group as herd sire in 1972. In the same year two Q ? were acquired from Barcelona, one of which, ‘Christmas’, reproduced and is still living in the herd. In 1976 Detroit died and ‘San Antonio l’, another unrelated 6, became the herd sire until 1980 when he was replaced by a second d from San Antonio Zoo, which was related to him. The current sires are ‘Von Zeppelin’ and ‘Rasmussen’, received from Budapest Zoo, and the herd has been divided into three groups, two of which are on exhibit; 13 specimens have been sent to other zoos for the establishment of new herds.

From 1960-1966 the herd was exhibited in a wire-enclosed paddock measuring 6 x 9 m with a substrate of hard-packed soil and con-

taining a double-walled wooden house measur- ing 2 . 5 X 1 . 8 ~ 2 m . In 1966 the herd was moved to an 0.06 ha paddock in the new Delicate Hoof Stock Area (Maloney, 1968). The paddock was terraced, each terrace being 4-5 m wide, and two stone walls 0 . 8 m high ran across the centre. The substrate was J cm blue stone which was later seeded with grass because the stone was too hard for the animals’ hooves. The group had access to a c. 8 x 5 x 3 m heated indoor enclosure which was also part of the public exhibit. The front and rear of the indoor area consisted of heavy gauge fencing which had a mesh of 10 x 15 cm; to prevent the gazelles’ legs from getting caught and calves from escaping through the wire, the mesh size of the first metre of the fence was later reduced to 1 . 3 x 1 . 3 cm. A bachelor herd of dd was kept in another area, not on public display.

When the herd outgrew its enclosure in 1973 it was moved to a larger paddock in the Delicate Hoof Stock Area. This paddock measures 0.11 ha and had originally a sub- strate of a mixture of hard-packed clay and blue stone but this was later turfed and a pool was added. At one end of the paddock there is a steep slope which is retained by an 0 . 5 m wide stone wall, screened at the top with wooden stockade fencing to prevent the gazelles from jumping off the wall into the yard below. At the other end there is a small area terraced with railway sleepers. Except for a 2 m moat the enclosure is surrounded by a 2 .2 m high chainlink fence. Within the pad- dock is a 4 . 6 ~ 9 . 8 ~ 2 . 2 m outdoor holding area for the herd sire. The gazelles have free access to a sunlamp-heated indoor stall and a c. 8 x 5 x 3 m indoor exhibit area. Hay is pro- vided as bedding. Dorcas gazelle dd have been kept successfully with our herd of Bongo Tragelaphus eurycerus. We have found that holding surplus dd in off-exhibit areas which are too small causes the animals to become agitated so that self-induced injuries result.

For each gazelle the daily diet consists of 0 .5 kg of pelleted herbivore feed, formulated at Washington NZP, 0.25 kg Omalene 100 and 0 . 5 flake alfalfa hay. The animals supple- ment the diet by grazing and browsing on the grass and fallen leaves in their paddock.

BREEDING 197

Parasites have been a persistent problem in the gazelle herd. Coccidia cysts (Ezmeriu has been identified) and several nematodes includ- ing Strongyloides and Trichuris have been found. The high parasite loads in the herd have been attributed to high population den- sity and also to coprophagy which causes the gazelles repeatedly to reinfest themselves (W. Peratino, pers. comm.) . Another contributing factor may be that the animals are exhibited on grass.

As a prophylactic measure gazelles are wormed every six weeks with a follow-up screening being given seven days later. Depending on the results of the faecal analysis appropriate anthelminthics are prescribed for specific infestations. The drugs normally used are: Telmin, Strongid T, Eqvalan, Panacur, Ripercol, Albon and Camvet. We have found that rotation in the use of the drugs is import- ant to prevent the parasites from becoming resistant to them, We have also found that, when used at the manufacturer’s recom- mended dosages, some anthelminthic drugs

(such as Telmin) are not always effective in controlling parasites at high herd densities.

REPRODUCTlON Since 1961 17 9 9 have given birth to a total of 112 calves sired by nine different dd, although 72% (80) were sired by only three of these, Pappy, Detroit and San Antonio 1, giving rise to 29,29 and 22 young respectively. The deleterious effects of inbreeding on the reproductive rate of the herd has been discussed by Ralls et al. (1 980).

As in other species of gazelle (Dittrich, 1968; Read & Frueh, 1980) there is no fixed breeding season in the Dorcas gazelle although Essghaier (1981) has reported two peaks of sexual behaviour, one in April and the other in November, in a wild population in western Libya. Births at Washington NZP have been recorded in all months of the year, with the greatest number between March and May and the fewest between November and February (Table 1). In 1977 a number of changes in herd management were introduced to promote

TOTAL

YEAR J A N FEB MAR APR M A Y JUN JUl. AUG SEP OCT NOV DEC (SEX RATIO)

1961 1 1 (0.1) 1962 1 1 2 (1.1) 1963 1 1 1 3 (2.1) 1964 2 2 (1 1) 1965 1 1 1 1 4 (1.3) 1966 2 1 1 1 1 6 (4.1.1) 1967 2 1 3 (1.2) 1968 1 1 2 1 5 (3.2) 1969 1 1 1 1 4 (3.1) 1970 2 1 2 1 2 n (3.5) 1971 1 2 1 1 2 7 (4.3) 1972 1 1 1 1 4 (0.3.1) 1973 1 2 1 1 1 6 (3.3) 1974 4 1 1 1 1 1 9 (2.7) 1975 3 2 1 1 2 9 (4.5) 1976 3 1 4 (4.0) 1977 1 2 2 1 1 3 in (4.6) 1978 1 5 6 (3.3) 1979 1 5 6 (4.2) 1980 3 2 5 (2.3) 1981 1 5 1 1 8 (5.2.1)

TOTAL 2 2 16 16 27 11 7 6 9 11 2 3 112 (54.55.3)

Table 1. Distribution of Dorcas gazelle Guzellu dorm births at Washington NZP by month and year.

198 BREEDING

DAM APPROXIMATE SEX RATIO MEAN INTERRIRTH AGE AT LAST LONGEVITY AGE A T FIRST OF BIRTHS INTERVAL PARTURITION (years)

(days) CONCEPTION (days) (years)

Granny unknown 4.9 305.5 10 .9+ 1 7 . 2 + * Reern 190 7.6.1 314.7 12.2 12.5 Greeny 599 10.9 271.2 15.5 15.7 Whitey 247 5.6 330.2 10.2 13.4 Holiday 685 2.1 445.0 Kelly 1143 0.1.1 965.0 Dottie 900 3.6.1 278.0 Judy 969 1.1 351.0 Flame 462 5.3 267.6 Christmas unknown 4.7 262.2 Gretchen 669 3.2 367.3 Daffodil 635 3.2 358.3 Crinkle 418 3.2 369.5 Cricket 1316 1 .O Garbo 1231 1 .o Griselda 58 1 1 .o Mean 716 310.8

(n = 14) (n = 95)

*euthanised

Table 2. Reproductive parameters and longevity for Q Dorcas gazelles at Washington NZP. Time of conception based on subtracting 172 days (mean gestation) from the date of parturition.

warm weather births and to avoid injuries to calves by the adult dd. Instead of housing the two sexes together, dd are now kept with the p p only in mid-winter and are removed again as soon as all the p q are judged to be pregnant. Before 1978 several p p regularly produced two young a year, but since then the trend has been towards more highly synchronised spring births.

The mean age at first conception for 14 q p of known ages was 716 days or almost two years. Sexual maturity is probably reached much earlier than this, however, as two p p were as young as six and eight months when they first conceived (Table 2 ) . Speke's gazelle G. spekei and Mountain gazelle G. gazella q Q have been reported to reach sexual maturity at about eight months of age (Mendelssohn, 1974; Read & Frueh, 1980). The age when dd reach sexual maturity is more difficult to determine because dd at Washington NZP have routinely been removed from the herd when six months old. The youngest d success- fully to inseminate p p at the zoo was 18

SIRt: AGE AT FIRS1' SEX RATIO LONOEVITY SUCCESSFUL OF mrrtjs (years) INSEMINATION

(days)

pappy Black and White Red Blue lletroit San Antonio 1 San Antonio 2 Rasmussen Von Zeppelin

unknown 610

2360 933

unknown unknown unknown unknown unknown

15.13.1 9 . 1 + 2.3 6 .8 5.7.1 10.2 1 .O 3 .3

13.16 4 .2+ 11.11 2.3 2.0 3.2.1

Table 3. Reproductive parameters and longevity for d Dorcas gazelles at Washington NZP.

months old (Table 3), which agrees roughly with Read & Frueh's (1980) report of a fertile copulation by a 16-month-old Speke's gazelle.

The gestation period in the Dorcas gazelle is about 172 days (Slaughter, 1971) and the median interbirrh interval among 13 9 p in our

BREEDING 199

herd was 271 days (mean=310-7, n=95), or about nine months, with a range of 177-965 days (Table 2). About 26% (25) of all intervals were less than 210 days, however, indicating that p p may show a postpartum oestrus. This may occur whether or not a p is lactating since in 17 (68%) of the 25 cases where conception occurred within 38 days of parturition the calves were still alive. Speke’s gazelle p p may also exhibit a postpartum oestrus regardless of whether the calf survived (Read & Frueh, 1980). Since 72% of the calves which were conceived within 38 days of parturition sur- vived to at least six months of age, concurrent gestation and lactation seem to have no ad- verse effects on a 9’s reproductive ability. There is no evidence that interbirth intervals get longer as the p grows older.

It appears that the sex of the previous off- spring influences the length of the subsequent interbirth interval. After dd were born the mean interval was 331 - 5 days while after the births of 9 9 it was 269 days; this difference is statistically significant (p < 0 * 02, Mann- Whimey U-test, two-tailed). The same trend is clear in five of the seven p p for which seven or more interbirth intervals were known (Table 4); similarly, among the 25 cases where inter- vals were less than 210 days the sex ratio of the previous calves was 8.17, that is, balanced

MEAN INTERVAL MEAN INTERVAL FOLLOWING FOLLOWING d BIRTH p BIRTH

(days)* (days)*

Granny Reem Greeny Whitey Dottie Flame Christmas

All 9 9 (n=13)

269.7 291.5 224.0 356.0 325 .O 246.5 294.3

331 .s (n = 44)

260-1 270.4 234.6

254.5 295.7

228.2

240. n 269.0 (n =49)

*for individual Q Q any interval greater than 500 days was excluded from the analysis

Table 4. Comparison of interbirth intervals following Q and d births.

in favour of p p. It is possible that in gazelles d calves are more ‘expensive’ for the p p to produce; in Speke’s gazelle dd are signifi- cantly heavier at birth than p p and appear to grow slightly faster in their first week (Read & Frueh, 1980).

The sex ratio at birth of the 11 2 calves born at the zoo was 54.55.3; the ratios of calves born to particular individuals are given in Tables 2 and 3. None of the individuals has produced significantly more young of one sex than of the other, nor have there been signifi- cantly biased sex ratios in any year since repro- duction began (Table 1). The Q ‘Whitey’, however, produced five dcf in succession and then six p 9, a sequence which is unlikely to occur by chance (p<O.O5, one-sample run test (Siegel, 1956)).

Observations on six pregnancies from three p p at Washington MZP show that full disten- sion of the udder is apparent two to four days prior to parturition, and partial distension may be seen as early as 14-23 days before birth. The temporal relationship between udder dis- tension and parturition appears to be quite variable; this has also been found for the Yellow-backed duiker Cephalophus sylvicultor (Kranz & Lumpkin, 1982). Although Dittrich (1968) notes that foetal movement may be seen between two and two-and-a-half months before birth, the earliest time we have observed this has been about two weeks before a calf was born. Just prior to parturition p p usually become restless and pace around their enclos- ure; a description of birth in the Dorcas gazelle is given by Walther (1968).

Dittrich (1968) and Read & Frueh (1980) found that gazelles most often gave birth in the early morning or at night. The same trend was not apparent for the Dorcas gazelles at the zoo where, of 19 births for which precise times are available, 11 took place between 0700 and 0900 hours and eight between 1300 and 1800 hours. We have not found it necessary to separate parturient p p from the rest of the herd, contrary to the suggestion by Dittrich (1968) and Read & Frueh (1980) that this may be necessary. All births in the herd have been singletons except for twin p p born in 1982. Twin births are infrequent in most gazelle species but have been reported for

200 BREEDING

Thomson’s G. thomsoni, Mountain, Goiter4 G. subgutturosa and Arabian gazelles G. gazella arabica (Crandall, 1964; Mentis, 1972).

MATERNAL CARE Dorcas gazelles are classic ‘hiders’ which means that newborn young lie concealed in vegetation or at the base of vertical objects, and are visited by their mothers periodically to allow them to nurse. Calves select their own hiding places and it is as yet unclear whether mothers call their young for nursing or whether the appearance of the mother induces the young to show themselves. The calves hide for two to six weeks (Walther, 1968) but even after this time mothers and young spend little time in contact. During observations on mother and young, Ralls and her associates (pers. comm.) found that during the calfs first four weeks it stayed more than two body lengths away from the mother for 100% of the

weight (kg)

observation time and between weeks 5 and 8 it stayed the same distance away for 68-96’/0 of the time. Nursing is infrequent, occurring at irregular intervals throughout the day, and individual bouts of suckling are fairly short, often lasting less than one minute (Ralls & Kranz, pers. obs.).

In captivity adult dd are generally indiffer- ent to calves, at least until young dd begin to mature, but some may attack calves and these have been removed as soon as young are born.

GROWTH AND DEVELOPMENT The measurements of one newborn d Dorcas gazelle calf were: weight, 1.72 kg; head and body length, 500mm; left ear, 70mm; left hind foot, 200 mm. As is typical in small ante- lope, weight gain is fairly rapid (Dittrich, 1969); the above-mentioned d almost doubled its birth weight to 3 .2 kg by week 3 and had reached about 24% (3.6 kg) of the adult

I I I I I I I

10 20 30 40 50 60 70 80 age (days)

Fig. 1. Growth curves for three d and one 9 Dorcas gazelle Guzelfu dorm at the National Zoological Park, Washington.

BREEDING 201

weight by week 4. At week 10 it weighed 6.2 kg or about 41% of the adult weight. One hand-reared Q showed a similar developmental trend (Fig. 1). This is comparable to what Dittrich (1969) predicted for small gazelle species.

Calves are a uniform light brown colour at birth, but the adult coloration is apparent by week 8. Horn buds appear between days 10 and 20 and the horns of dd may grow to a mean length of 23 cm by the time they reach adulthood (Osborn & Helmy, 1980). In one d the testes descended on day 5. Calves start nibbling at vegetation during their first week and, although the natural weaning age is not known, hand-reared calves have been weaned successfully at three weeks of age.

During the last 20 years 13 calves have been hand-reared at Washington NZP for a variety of reasons, including rejection by the dam, inadequate milk production or maternal care, and extreme weakness in the calf. Potentially surplus dd have often been hand-reared to make them more tractable for crate training and subsequent shipping. The feed regime for one hand-reared p is given in Table 5.

LONGEVITY Dorcas gazelles can live extremely long in cap- tivity. One Q, Granny, lived over 17 years at the zoo before being euthanised. Three other p 9 , born at the zoo, lived 12 years six months,

13 years three months and 15 years nine months respectively (Table 2). Based on the limited data available, the lifespan of dd may be slightly shorter. The longest lived d at Washington NZP died aged ten years one month, and Pappy who, like Granny, was 12-18 months old on arrival, lived for nine years (Table 3). Data on longevity in Dorcas and other gazelle species indicate that a life- span of eight to 14 years in captivity is not unusual (Mentis, 1972). At Washington NZP 67 of 112, or 6O%, of calves born survived to at least six months of age. Survivorship and sources of mortality on juvenile captive Dorcas gazelles are reported in Ralls et al. (1980).

OTHER MANAGEMENT CONSIDERATIONS As a result of our experiences with the Dorcas gazelle several recommendations can be made concerning its management in captivity. Cliffs and terraces should be avoided in the enclosure design because Dorcas gazelles seem to have poor depth perception and occasionally injure themselves by jumping off such structures. Outdoor exhibit areas should have a flat or gently sloped topography, and the best sub- strate to use is hard-packed clay or hard- packed fine stone chips or dust. Gazelles can be exhibited on grass but, at least in temperate areas, this may lead to increased parasite infestation.

When introducing a herd into a new enclos-

~~ ~~

FORMULA SUPPLEMENTSllOO g FORMULA FEEDSlDAY AMOUNTlFEED AGE

(g) (days)

Cow colostrum none 6 not recorded I

1 : 1 evaporated

3 : 2 evaporated

milk/water 2 drops Abdec 6 50 2 4

milk/water 2 drops Fer-In-Sol 5 56 6-29 2 drops Abdec,

2 drops Abdec, 2 drops Fer-In-Sol, 2 . 5 g Esbilac 5 75 3 0 4 6

4 110 47-48 3 140 49-79 2 160 80-86 1 c. 200 87-93

Table 5. Feed regime for a Q Dorcas gazelle hand-reared at Washington NZP.

202 BREEDING

ure it is wise to mask fencing with tennis net- ting or canvas for the first few weeks to prevent the animals from running into the fence. Alternatively the fence can be flagged with strips of surveyor's tape, canvas or tissue paper, this last having the d d e d advantage of being inexpensive and lasting for only a few weeks.

Although the Dorcas gazelle is a desert species, given the appropriate care it can do well during winter in temperate climates. The timing of births, for instance, should be managed by introducing adult dd to Q herds at one particular time of the year so that all calves are born in the spring and summer. Ani- mals should have access to a warm, draught- free indoor area but need to be confined inside only when there is ice or ice-glazed snow on the ground since they tend to slip on ice or break through the crust and injure or break their legs. Surplus dd can be kept together in bachelor herds but d-only groups should not be kept in enclosures which allow them to have visual or tactile contact with ~p since their constant efforts to gain access to them often result in injuries.

Dorcas gazelles are attractive animals and a group makes an interesting, lively exhibit. They are also increasingly rare in the wild and, despite the relative ease with which they can be maintained and bred in captivity, few zoos exhibit them. We hope that by presenting this history of the herd at Washington NZP we have stimulated greater interest in the species.

ACKNOWLEDGEMENTS We thank Sonny Stroman, Barbara Bingham, Bess Frank, Maggie Morton and Willie Peratino for contributing to the data reported here, Ann Fick for organising and tabulating the data on reproduction, Judith Block for her care in maintaining the records, and Katherine Ralls and Judith Block for reading an earlier draft of the manuscript. Judy Gradwohl kindly prepared Fig. 1. A special thanks goes to Harold Egoscue for his early and sustained interest in Dorcas gazelle management. We also thank the Friends of the National Zoo (FONZ) for financial support.

PRODUCTS MENTIONED IN THE TEXT Abdec vitamins: manufactured by Parke-Davis, Division of Warner-Lambert Company, Morris Plains, NJ 07950, USA. Albon: sulfadime thoxine, anthelminthic, manufactured by Roche Chemical Division, Hoffman-La Roche Inc., Nutley, NJ 071 10, USA.

Camvet: cambendazole, anthelminthic, manufactured by Merck Animal Health Division, Merck & Co. Inc., Rahway, NJ 07065, USA. Carnation evaporated milk: manufactured by Carnation Company, Los Angeles, CA 90036, USA. Eqvalan: ivermectin, MSD, anthelminthic, manufactured by MSD AGVET, Inc., Subsidiary of Merck & Co. Inc., Rahway, NJ 07065, USA. Esbilac: milk formula, manufactured by Borden Inter- national, 420 Lexington Avenue, New York, NY 10017, USA. Fer-In-Sol iron supplement: manufactured by Mead Johnson Nutritional Division, Mead Johnson & Co., Evansville, IN 47721, USA. NZP herbivore diet: pelleted feed, manufactured for Washington NZP by Zeigler Brothers, Inc., POB 95, Gardners, PA 17324, USA. Omalene 100: a sweet feed, manufactured by Ralston Purina Company, Checkerboard Square, St Louis, MO 63110, USA. Panacur: fenbendazole, anthelminthic, manufactured by American Hoechst Corporation, Animal Health Division, Somerville, NJ 08876, USA. Ripercol: levamisole hydrochloride, anthelminthic, manufactured by Cyanamid Agricultural De Puerto Rico, Inc., Manati, Puerto Rico 00701. Strongid T: pyrantel pamoate, anthelminthic, manufac- tured by Pfizer Inc., Department of Veterinary Medicine, New York, NY 10017, USA. Telmin: mebendazole, anthelminthic, manufactured by Pitman-Moore, Inc., Washington Crossing, NJ 08560, USA.

REFERENCES CLOUDSLEY-THOMPSON, J. L. .4 GHOBRIAL, I.. (1965): Water economy of the Dorcas gazelle. Nature, Lo&. 207: 13 13. CRANDALL, L. s. (1964): Management of Mld mammals in cuptivify. Chicago: University of Chicago Press. DITTRICH. L. (1968): Keeping and breeding gazelles at Hanover Zoo. Int. Zoo Yb. 8: 139-143. DITTRICH, L. (1969): Birth weights and weight increases of African antelopes at Hanover Zoo. Int. Zoo Yb. 9: 118-120. ESSGHAIER, M. F. A. (1981): Ecology and behavior of Dorcas gazelle. Unpublished PhD thesis, University of Idaho. GENTRY, A. W. (1971): Genus GazeLla. In The mammals Qf Afda. An idenhfication manwl 15.1: 85-93. Meester, J. & Setzer, H. W. (Eds). Washington, DC: Smithsonian Institution Press. IUCN (1972): Red data book 1: Mammalia. Morges: Inter- national Union for the Conservation of Nature and Natural Resources. KRANZ. K. R. & LUMPKIN, s. (1982): Notes on the yellow- backed duikkr Cephalophur sylvicultor in captivity with comments on its natural history. Int. Zoo Yb. 22: 232-240. MALONEY, F. A. (1968): Hoofed animal exhibits at Washington Zoo. Int. Zoo Yb. 8: 90-91. MENDELSSOHN. H. (1974): The development of gazelles in Israel and their behavioural adaptations. In The behaviour ofungulates and its relationship to management. Geist, V. & Walther, F. (Eds). IUCN Publs (N.S.) No. 24: 722-743.

BREEDING 203

MENTIS, M T (1972): A review of some life history features of the large herbivores of Africa. Lammergqeer 16: 1-89, OSBORN, D. J. & HELMY, L (1980): The contemporary land mammals of Egypt (including Sinai). Fieldiana: Zool.

RAILS. K , BRUGGER. K . & CLICK, A. (1980): Deleterious effects of inbreeding in a herd of captive Dorcas gazelle Guzellu dorcas. Int. ZOO Y3. 20: 137-146. READ. 11 & FRUEH, R. J. (1980): Management and breeding of Speke’s gazelle Gazella spekei at the St Louis Zoo, with

(N.S.) NU. 5: 1-579.

a note on artificial insemination. Int. Zoo Y3. 20: 99-104. SIEGEL. s. ( 1 956): Nonparametric statistics f i r the behavioral sciences. New York: McGraw-Hill Book Company, Inc. SLAUGHTER, L. (1971): Gestation period of the Dorcas gazelle. 3. Mammal. 52: 480-481. WALTHER, F R (1968): Verhalten der gazellen. Neue Brehm Biich. No. 373.

Manuscript submitted 3 September 1982