34(\ '1? Reprinted from the International Zoo Yearbook Vol. 18 1978

Reproduction in captive-born zorillas Idonyx striatus [Plate 38] at the National Zoological Park, Washington

MARION P. BALL Friends of the National Zoo, National Zoological Park, Smithsonian Institution, Washington, DC 20009, USA

The zorilla or Striped polecat Ictonyx striatus is a blastocyst remains unimplanted; this is not small terrestrial mustelid which inhabits most of known in eastern populations (Mead, 1968). the African continent south of the Sahara and perhaps the western portion of Asia Minor HOUSING AND CARE (Shortridge, 1934). Nocturnal and solitary, it is The zorilla adapts readily to captivity. When found in a variety of habitats, primarily in taken young, it becomes quite tame and friendly semi-arid rock and scrub areas and frequently and even adults adjust quickly to routine pro- near human habitations where it preys upon cedures, using their defensive spray only when domestic fowl as well as small rodents, insects, annoyed, frightened or handled. Average life reptiles, eggs and birds (Grzimek, 1975; Walker, span in captivity appears to be about five years 197)). Parts of its range it shares with two smaller (Shortridge, 1934; Crandall, 1964). Once com- related species, the North African or Libyan mon in zoos, the species is now rare in collections striped weasel Poecilictis libyca and the White- and despite its former popularity there are com- naped weasel Poecilogale alhinucha, which are paratively few instances of captive births; basically similar in habits, black-and-white according to Yearbook records, the only recent colouration and diet. Almost nothing is known of centres of consistent breeding, apart from the the reproductive biology of these two weasels National Zoo, are Toronto and Stuttgart zoos. (Rosevear, 1974; Walker, 1975). The National Zoological Park received its In colouration and general behaviour the breeding pair in September 1975 from Toronto zorilla also resembles its better documented New Zoo, where the animals had been born of wild- World counterpart, the Spotted skunk Spilogale caught parents. At that time the $ was approxi- putorius, including the defensive ability to spray a mately seven months old and the $ about one foul smelling secretion from the anal glands. year. Since their arrival they have been housed The Spotted skunk, however, exhibits several in a variety of indoor enclosures in the Small interesting differences. More arboreal than the Mammal House, ranging in floor area from zorilla, its nest site entrances have been located 1-2 x 1-5 m to 3-5 x 1-5 m and 2-1 mhigh. They some 6 m above ground level in hollow trees have at various times been kept under natural (Crabb, 1948). In addition, western forms are light (from overhead skylights), artificial light, known to be subject to delayed implantation, and under a reversed light cycle in the nocturnal which results in a gestation period of up to 230 section of the building; in the nocturnal room they days, including the 180-200 days when the experience 12 hours of'daylight' and 12 hours of BREEDING HI subdued, blue 'twilight' during public hours. Pine kept under subdued lighting in a nocturnal bark chips or hay are used as a cage substrate and exhibit, they have been active at all hours. The the soiled litter is removed and replaced daily; usual gait is a brisk trot with the back slightly the enclosures are given a complete overhaul arched; the $ generally carries his tail in a vertical twice weekly. Natural hollow logs and halved position while the $ carries her horizontally with sections of cork bark logs provide shelters for the tip dragging. Interaction between the two, sleeping and concealment. apart from sharing a sleeping site, is limited to Feeding takes place once a day between 1400- apparently random encounters. On these occa- 1500 hours. Adult zorillas each receive one-third sions the 9 will yield to the

DATE OF DATE OF GESTATION NO. OF AGE AT CAUSE OF MATING BIRTH* PERIOD (days) YOUNG DEATH (days) DEATH

7 Feb 76 I 3 unknown 12 Feb 76 18 Mar 76 35 3 I, 3, 10 disappeared, presumed eaten by 9 7 May 76 I.O.I 14.23 killed by 9 27J11I76 31 Aug?6 35 0-2 survived * a fifth litter (1.0) was born 20 Mar 1977 and has been reared by the 9. Table I. Breeding record of a pair of captive-bred zorillas Ictonyx striatus which arrived at the National Zoological Park, Washington, in September 1975 at the age of seven (?) and 12 {S) months. 142 BREEDING

Four litters have been born between February All the births have taken place between 0700- and August 1976, but in only the last of these 1130 hours. The

cage in a mutilated condition; cause of death their interest and co-operation and for their superb care could not be determined. This agitated carrying of the animals. Special thanks also to Mr Harold Egoscue, Mammalogist, for his encouragement and assistance and behaviour was not repeated with subsequent to Mr Miles Roberts, Curator, who made possible the litters. entire project. To reduce stress to a minimum, no attempt was made to handle or weigh any cubs when young, PRODUCTS MENTIONED IN THE TEXT nor to observe them while they were still in the Feline Diet: manufactured by Central Nebraska nest. They were first seen outside during the Packing Co., North Platte, Nebraska, USA. fourth week, and in their seventh week were Felocine: killed feline distemper vaccine, manu- factured by Norden Laboratories, Lincoln, Nebraska observed eating chicks; it is not certain, however, 68501, USA. whether they had taken solid food previously. At Halo thane: gas anaesthetic, manufactured by Ayerst 16 weeks they were separated from the ?. The Laboratory, New York, NY, USA. weight of the first, three-day-old infant at death Trioid Plus: killed canine distemper/hepatitis vaccine, manufactured by Fromm Laboratories Inc., Grafton, was 14-9 g. At four months 21 days, the two Wisconsin 53024, USA. cubs of the fourth litter weighed 828 and 842 g. REFERENCES AUTHOR S NOTE CRABB, w. D. (1948): The ecology and management of A fifth litter consisting of one <$ cub was born 20 March the prairie spotted skunk in Iowa. Ecol. Monogr. 18: 1977 and has been raised by the mother; at time of 201-212. writing it is doing well. Like the third and fourth litters, GRAND ALL, L. s. (1964): Management of wild mammals in the 9 gave birth in a tunnel in the hay which she had captivity. Chicago & London: University of Chicago constructed herself, although, as before, a nestbox and Press. hollow logs were available. She also fashioned several GRZIMEK, H. c. B. (1975): Grzimek's animal life encyclo- hollows in the hay, connected to the den by a series of paedia 12. Chicago: Van Nostrand Reinhold Co. tunnels, and used these as resting sites, carrying the cub MEAD, R. A. (1968): Reproduction in western forms of with her and remaining in the rest sites for periods of the spotted skunk (genus Spilogale). J. Mammal. 49: one to two hours at various times throughout the day. No night observations were made. As in the previous 373-39°- ROSEVEAR, D. R. (1974): The carnivores of West Africa. births, the cub was moved into the L-shaped nestbox London: British Museum (Natural History). when it was a few weeks old. The adult o* was present SHORTRIDGE, G. c. (1934): The mammals of Southwest in the enclosure during this last birth, which had not Africa 1. London: William Heinemann Ltd. been anticipated, and was removed when the ? exhibited WALKER, E. P. (1975): Mammals of the world 2. 3rd ed. extreme aggressive behaviour towards him, attacking, Baltimore: Johns Hopkins Press. biting and emitting loud, shrill shrieks.

ACKNOWLEDGEMENTS I wish to express my most sincere thanks and gratitude Manuscript submitted if April (revised Septem- to all of the keepers in the Small Mammal House for ber) 1977

Printed in Great Britain by Henry Ling Ltd., at the Dorset Press, Dorchester, Dorset