Hystrix It. J. Marnrn. (n.s.) 12 (I) (2001): 7-9

OBSERVATION OF LARGE GROUPS OF GAMBIAN MONGOOSES (MUNGOS GAMBIANUS, OGILBY 1835) IN SOUTHEASTERN SENEGAL

CLAUDIO SILLERO-ZUBIRI* AND FrLrwo B ASSIGNANI”

* Wildlife Conservation Research Unit - Zoology Department, South Parks road, Oxford OX1 3PS, UK Dipartimento di Biologia Evolutiva e Funzionale, vide delle Scienze, Universitd di Par- ma, 43100 Parnza, Italy

ABSTRACT - We recorded 18 observations of Gambian mongooses (Murzgos gambianus), including a group of over 40, in south-eastern Senegal. The following paper contains some data on the behaviour, group size and time of activity of this scarcely studied species.

Key words: social mongooses, Mungos garnbiarzus, group size, social carnivore.

INTRODUCTION mongooses (Crossarchus spp.), it is one of The Gambian mongoose (Mungos gambianus) the least known of all cooperative carnivore is restricted to an area between southern Sene- species (Nowak, 1991). Our notes add to ex- gal and the Niger River, to West Nigeria. It is isting knowledge on the distribution and group a diurnal gregarious mongoose that inhabits size of this species. moist savannahs, forest-cultivation mosaics, grasslands and woodlands and has a diet which STUDY AREA AND METHODS predominantly consists of invertebrates (King- The Niokolo-Koba National Park of south- don, 1997). This species seems to be wide- eastern Senegal (13”N; 13”W) is one of the spread and locally common. largest conservation areas of West Africa. To- Out of the 22 species of mongoose described gether with the adjacent Badiar National Park for continental Africa (Wilson and Reeder, and N’Dama forest in Guinea, it forms the 1993), seven are considered “fully social” Transfrontier Park Niokolo Badiar, covering (Ewer, 1973) or “obligate communal breed- an area of over 10,000 km2 of Sahelian-Su- ers” (Creel and Creel, 1991). Only three of danien savannah, with Guinean woodlands, these species have been studied in detail (Estes, dry forests and gallery forest bordering the 1991 ; Kingdon, 1997). Research into the so- Gambia River and its tributaries (Sillero-Zu- cial groupings of banded mongooses (Mun- biri and Marino, 1997). Rainfall averages gos mungo), dwarf mongooses (Helogale 1,100 mm with a single rainy season from parvula) and meerkats (Suricata suricatta), June to October. The carnivore community all of which display some of the most elabo- here is very diversified: there are 23 species rate social systems found in mammals, has from 6 different families representing 3 1% of contributed considerably to the understand- the 75 carnivore species living in continental ing of cooperative breeding in mammals (e.g. Africa (Kingdon, 1997; Sillero-Zubiri and Rood, 1974; Rasa, 1985; Creel and Creel, Marino, 1998). 1991; Doolan and Macdonald, 1997). In this Data were collected during a study of the context, the Gambian mongoose is particu- Niokolo carnivore community in 1996 and in larly interesting as, together with kusimanse 1997. Daily field searches were carried out 8 C. Sillero-Zubiri and E Bassignani from a 4WD vehicle, driving at a speed of 20- of aggression or competition were noted, al- 30 km/h and totalling 22,500 km. Searches though the observation was short lived and were also carried out during night drives and the animals vanished quickly into thick un- during stationary searches at marshes. For dergrowth. Since in all other social mongooses each observation, the species, location (by studied packs are reciprocally intolerant (e.g. means of a hand-held GPS), number of ani- Rasa, 1985; Macdonald, 1992) the group we mals, age and sex class, habitat preference observed must have been a large single pack. and activity were recorded. Mongoose groups as large as this one have only been ever observed in the banded mon- RESULTS AND DISCUSSION goose (Rood, 1974), with one record of a group of nearly 70 (Estes, 1991). The band- Eighteen observations of Mungos ganzbianus ed mongoose is closely related to the Gam- were recorded during the study, totalling a bian mongoose and in East Africa a mean minimum of 120 individuals, fourteen in the group size of 14-16 individuals has been morning (8:OO - 10:OOh) and four in the recorded (Gittleman, 1989), the largest among evening (18:OO - 19:OOh). The daytime fre- social mongooses (Nowak, 1991). quency of observations along roads was 0.08 Mungos gambianus is relatively abundant in sightings per 100 km, or 0.01 per hour. Most Niokolo-Koba. Only banded and slender mon- observations consisted of bands of 3- 10 mon- gooses (Galerella were seen more gooses; the mean group size was 6.7 (&SD= sanguinea) frequently. Glimpses of its ecology and so- 8.9; n= 18); 5-7 was the mode and single in- ciability during this study suggest that, with dividuals were observed five times. Three habituation, the Gambian mongoose in Nioko- groups of 10 or more individuals were record- lo-Koba would provide a suitable subject for ed, including one of over 40 animals. The lat- a graduate study. ter was observed on 11 June 1996 at 19:OOh (13’2.700’N; 13’18.650’W) spread over an ACKNOWLEDGEMENTS area of 1,000 m2, with distances between in- dividuals ranging from 0.1 to 5 m. The group We wish to thank Dr. Harry Van Rompaey and Prof. was foraging when the passage of our vehi- Gilbert0 Gandolfi for their helpful suggestions. cle made them run for cover. The nearest in- dividuals were 5-10 m from the vehicle. The mean group size we calculated from our REFERENCES observations in Niokolo-Koba is most likely Bourliere, F., Minner, E. and R., Vuattoux, an underestimate, due to the fleeing behav- 1974. Les grands mammifers de la region iour and preference for thickets of this shy de Lamto, Cote d’lvoire. Mammalia, 38: species, which during this study preferred 433-447. woodlands, and used termite mounds to shel- Creel, S.R. and Creel, N.M., 1991. Energet- ter. To our knowledge, the observation of 40 ics, reproductive suppression and oblig- individuals in one group is the largest group ate communal breeding in carnivores. Be- ever recorded for this species, with a maxi- hav. Ecol. Sociobiol., 28: 263-270. mum group size of up to 31 individuals re- Doolan, S.P. andMacdonald,D.W., 1997. Band ported previously (Bourliere et al., 1974). structure and failures of reproductive sup- Large groups like the one observed may be pression in a cooperatively breeding car- either an exceptionally large pack, or an un- nivore, the slender-tailed meerkat (Suri- common situation in which two packs might cata suricatta). Behaviour, 134: 827-848. have been foraging together or engaged in Estes, R.D., 1991. The Behaviour guide to some sort of territorial behaviour. We were African mammals. The University of Cal- unable to determine whether the group was ifornia Press, Berkeley, Los Angeles, Ox- composed of one or more packs, and no signs ford. Observnrioii of large groiips of Garizbiari mongooses 9

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