Z!. Garten N. F., Leipzig 42 (1972) 5/6, S.296-33 Zlgisk Labratrium ved Kbenhavns Universitet Observatins n the Sumatran Rhin (Dicerrhinus sumatrensis) at Cpenhagen Z By RALPH SONNE-HANsEN, Kbenhavn With 6 Figures Intrductin The Sumatran Rhincers is a very rare species. Prbably arund 1 specimens survive (SINAGA 197, letter t the authr). Literature n the species hardly exists, and therefre the behaviur f the species was investigated in cnnectin with a curse in ethlgy. Because f limited time the investigatin was superficial. I intended t cntinue my studies later, but meanwhile the animal has died. This cntributin is therefre purely preliminary. It is published because s little is knwn abut the tpic and in memry f "Subur". Material and Methds "Subur" (Sj2) was captured in 1959 n Sumatra (ANDERsEN 1961). She was prbably brn in 1956, and frm 4/12-1959 she was at the Cpenhagen Z where she died 24/2-1972. Apart frm ccasinal visits the bservatins were carried ut frm 2/3 t 1/4-197, 9 a. m. t 5 p. m. each day. As the behaviur was rather unifrm frm ne day t anther, this time-factr is largely ignred. The rganizatin f the cage was cnsidered, because it limits the bilgical pssibilities f the animal. Limitatins placed n the cllectin f data presented here, were the pening-hurs f the Z as well as the time f the year. Apart frm direct bservatins made by the authr persns having direct knwledge abut the animal have been interviewed. Measurements were made with 2 m rule and wrist-watch. Results and Discussin General infrmatin The weight f the rhin was f"'.i9 kg. She was 2 cm lng frm the nse t the base f the tail, abut 135 cm ver the shulders, and the head was abut 6 cm lng. Her ftprint was 2-25 cm acrss and 25-3 cm lng when measured in lse snw. The distance between her ipsilateral ftprints varied between 4-8 cm. When walking she sme- times ambled and smetimes she mved her legs frward in the sequence: left freleg-right hind leg-right frelegleft hindleg etc. Tw legs generally mved at the same time. It was bserved that the legs were raised high, prbably as a result f adaptatin t a
297 R. SO:\,NE-I-I.NSE.\', Obscl'va li ns n the SUrnall'an Rhin swampy habitat. This adaptatin t a swampy habitat is emphasized by the smth underside f t he hves, which spread when she walked. She slid a little n the cement flr f the indr cage. It was therefre suggested that flrs in such cages have rugh surfaces. "Subur's" diet usually cnsisted f the fllwing: mainly beets, sme apples, a few bananas, a laf f rye bread cut t pieces and an range served in tw I, f,' t. '.. w '" P< I'..; I a.=: e " ;;" "" ::: Z.; '" cs "... :g "....=: ".S '" :;;;" d j" ",.; tlj.. '....
298 R. SO:\,NE-HAXSEN, Observatins n the Sumatran Rhin.s... $ >::..!::: e: SJDq UOJ!...:t C5 c WZ WCS SJOJ!S!A I::l H a5... ;::I S 'd -4:::: q"... 'd.s Q) :S C; Q).S i 1 ; buckets (,.-.,15 L per bucket) arund nn. Furthermre she ate abut 1 kg alfalfa-hay f the 25 kg daily prvided. She had a rather lng nse (prbscis). Frm an eclgical pint f view this species is equivalent t the Black Rhincers being a brwser, mstly eating yung leaves, twigs and bark (HANSTROM 196, SINAGA 197, letter t the authr). In the Z it seemed a little difficult fr her t cnsume the slices and lumps f laf and beets. The lwer jaw was placed belw the fd, then the upper lip (prbscis) pushed it in. A bucket f beets was cnsumed in apprximately half an hur. When drinking the muth was clse t the surface f the water, and the water was sucked and r lapped up. Befre describing mre cmplex behaviur an utline f the cage is given (Fig. 2)..
R. SO:\TXE-!-!ANSE:\T, Observatins n the Sumatran Rhin 299 Diurnal rhythm In nature the species is active by night (DYHRBERG 197, persnal cmmunicatin). In the Z there was much nise during daytime, but "Subur" slept fr several perids each lasting frm 3-6 min. She slept particularly arund nn and in the afternn. She ften slept with her back against the public and in the hay cck (Fig. 3). When it was getting dark she whimpered mre rarely Fig.3. "SubUl'" ften slept with her back t the public r in the hay and ate a lt while walking arund in the cage. The ears std perpendicular ut frm their base and turned in different directins. Unfrtunately it was nt pssible t visit her by night, but accrding t the night-watchman she was very active. Pendulatin These mvements are extremely steretyped and have arisen r at least hypertrphied in ca pti vi ty. The pendulatin has nt heen bserved in wild animals (DYHRBERG 197, persnal cmmunicatin). It was weakly develped when the animal arrived at Singapre (SCHIOTZ 197, persnal cmmunicatin), and has grwn mre and mre intense since then. The head was lwered s that the nse was abut 3 cm abve the flr, and the head mved laterally frm ne side t the ther (pendulatin). These mvements mainly tk place in the frenn, in the afternn nly rare sequences f 2-6 pendulatins were nted. Furthermre the pendulatin was lcalized t a specific place in the indr cage. It always ccurred with the head directed twards the public and the tail twards the little windw t the left f the nameplate (Fig. 4). When nt interrupted pendulatin ccurred 74-78 times a minute fr abut 4 hurs daily. The Sumatran Rhin is a brwser, s this mvement culd pssibly have develped frm feeding mvements. In the Z the pendulatin was never b- III Fig. 4. Pendulatin tk place-with the head directed twards the public and the tail twards the little windw. - She ften urinated in this psitin
3 R. SONNE-HANSEN, Observatins n Lhe SUlnaLran Rhin served in the utdr cage, where there is rm fr exercise. S need f exercise may be a factr in the cause and effect cmplex. On the ther hand pendulatin may be regarded as a pathlgical behaviur because f "bredm" (spacecnfinement, lack f ccupatin, lack f a scial cmpanin). If yu pulled "Subur" in the ears, she didn't stp pendulating. Pendulatin ceased upn entry int the cage. Perhaps the pendulatin culd be reduced with suita ble cmpany and mre space. When pendulating the fremst hrn ften pushed against the vertical irn bars f the cage. Rubbing The animal rubbed her head and fremst part f her bdy against the bars. The frnt hrn was placed between the bars twards the public r the pl and mved vertically. The frnt hrn was much wrn and nce brke ff (2/8-1964) (Fig. 4). Rubbing may have a beneficial effect n the skin cnditin, but culd be caused by scial needs. Furthermre the skin may have been t dry in winter-time, because the animal never used the indr pl fr bathing. A shwer was recmmended fr the sake f her skin, and wden bars wuld have been preferable t the irn bars f the cage t minimize inj ury. Gathering f hay Mre than half f the 25 kg f hay she gt a day was placed n the hrns, s that the eyes were cvered. In this cnditin she walked abut the cage nce r twice. This behaviur may have a "play-functin" r perhaps a sexual ne (?). She ften pitched the hay in the pl. This was perhaps t sterile. Bathing The cnditins indrs and ut f drs are different. In winter "Subur" nly had the indr pl which cntained 1-5 cm f water. The indr pl is abut 8 m 2, s that she culd hardly turn arund. She entered the pl 2-5 times a day, but she never lay dwn. Maybe the water was t cld r t sterile. In nature the species spends hurs bathing in mud. The indr pl is nt equivalent t natural slughs. In summer she had the utdr slugh. Here the temperature may be rather high, and she spent a lt f time just lying here. Urinatin and defaecatin Urinatin might take place everywhere in the indr cage, but was mst frequent with the tail directed twards the windw t the left f the nameplate (Fig. 4). She had tw patterns f urinatin. Mst frequently she sended a jet f urine right backwards abut 15 abve hrizntal level. Immediately befre urinatin she mved the tail away. The wall arund the name-plate clearly shwed that she mstly hit here when pendulating. Out f drs urinatin was nt lcalized. The jet f urine was abut 3 m lng, and she urinated 1-4 times in successin. She urinated 1-24 times hurly. Only n
R. SOX:\, E-I-I."-NSE.'I, Observatins n the Sumatran Rhin 31 ne cc a s in I b s e r v e d her u r i n a tin g li k e a cw. In this case the urine fell right dwn. Whether this difference has relatin t hrmnal cycle, demarcatin f territry r smething else is nr knwn. Indrs defaecatin tk place at the stairs t the pl r in the pl. Like the Tapir (Tapirus indicus) next dr she had "lcalized excretin" (HEDIGER 192). This lcalized excretin may be adaptive in several ways. She will leave n track f faeces behind her fr predatrs t fllw. And perhaps the slughs are demarcated with faeces and phermnes, s that ppsite sexes may find each ther. Out f drs the slugh was filled with faeces t a certain extent. Paths The indr cage is s little (21 m 2 ) that "Subu'r" walked everywhere nw and then. She preferred ne path, hwever (Fig. 5). Of the tw pssible directins in the steretyped rute, she mstly walked in the directin f the great arrw- Fig. 5. Indrs "Subul''' molit ften fllwed this circular rute. Predminantly in the directin f the great Il.rrw head seen in Fig.5. She mstly walked the directin f the little arrw when leaving the pl. These paths were nt fllwed strictly, amng thers because f stimuli frm the public. Out f drs I nly bserved her n three ccasins because f the winter. On an ccasins, each f ne half hur duratin, there was snw. This situatin Fig.6. In the utdr sectin "SubUl'" (in winter) fllwed circular rutes. The thickness f the rutes indicate their relative imprtance. ) means that she ften turned arund here
32 R. SO NE -HANS E, Observatins n the Sumatran Rhin is f curse nt natural fr the species, but she nevertheless fllwed rund, steretyped paths, easy t see in the snw. Furthermre ne culd read the relative imprtance f the different paths (Fig. 6). This pattern may partly result because f the uneven grund with different snwdepth. Fr instance the slpes f the slugh is cvered with 15 cm f snw when the rest f the area is cvered with 8 cm. One culd see that she mstly fllwed the lng sides and walked in circles. The arrwhe.ads seen in Fig. 6 indicate that she walked in the respective directins. The fat path she fllwed in bth directins, and she ften turned arund chsing this instead f ne f the secndary paths. Whether this pattern will be the same in summer is nt knwn. She walked very cautiusly in snw, and prbably preferred well-knwn paths. In nature the species is said t fllw specific paths related t specific fdplants (HANSTROM 196, DYHRBERG 197, persnal cmmunicatin). The z-pattern culd be a reminiscence f natural habits, n the ther hand circular figures are cmmn amng captive animals (HEDIGER 195). Scial needs In nature the species is prbably slitary, but live in pairs at least part f the time (DYHRBERG 197, persnal cmmunicatin). Steretyped behaviur may have arisen because f scial needs. Several bservatins indicate need f cntact: a) she rubbed herself as already mentined; b) she immediately came when guests wanted t feed her; c) she nw and then std fr a lng time when tuched between the flds f the skin; d) she intensively sniffed t the Tapir living next dr, when they met in the indr pl at rare intervals; e) nce a cw went int her cage, and she seemed t be very interested, unfrtunately this cmpanin was remved again! She prbably ught t have a cmpanin either f the same r anther species. Squeaking "Subur" had a specific, shrt squeak. Smetimes she rarely squeaked and smetimes very ften. One day she squeaked incessantly frm 3 p. m. t 5 p. m. Usually she squeaked nce every half hur. Did she call fr cmpanins? Raising f hind legs When pendulating she alternately raised ne f the tw hind legs. Smetimes ne f the hind legs was raised when she was just standing. She changed leg after 2-3 minutes. Out f drs all legs were in use, and they functined perfectly. Whatever the reasn may be, leg-raising is als knwn frm ther animals in captivity. One f the Z's grillas had the same habit. There may be a relatin between pendulatin, squeaking, raising f hind legs and need f scial cntact. This descriptin is partly cmmn t a lt f zanimals.
R. SONi\'E-fIA:\"SES, Observatins n the Sumatran Rhin 33 Acknwledgments The authr is indebted t the fllwing persns fr discussins, help and cmments upn the manuscript: J. CAMPSIE, A. DYHRBERG, G. MLLER, E. PARBST, H. POULSEN, A. SCHIOTZ, keepers in the Cpenhagen Z and my father. Summary A Sumatran Rhincers ( ) was bserved fr a shrt perid. The behaviur was described in general and steretyped behaviur was emphasized. Outstanding amng steretyped mvements was the pendulatin f the head frm ne side t anther, the tracks cnnected with mvements frm place t place and that she raised her hind legs alternately when pendulating. Zusammenfassung Im Fruhling 197 wurde das Verhalten eines Sumatranashrn- (Dicer-r-hinus sumatr-ensis) bebachtet. Das Nashrn war ungefahr 14 Jahre alt und hatte 11 Jahre davn im Zlgischen Garten Kpenhagen verlebt. Es war hauptsachlich in del' Nacht aktiv. Am Vrmittag pendelte es mit dem Kpf vn links nach rechts (AbbA). Es rieb besnders den Kpf gegen die Stabe des Kafigs. Es badete nicht im kleinen, reinen Wasserbecken im Hause, dagegen in del' SchlammpfUtze au13erhalb des Hauses (Abb.2). Es urinierte auf zwei verschiedene Weisen. Es knnte entweder einen Strahl 3 m ruckwarts spritzen der wie eine Kuh das Wasser einfach fallen lassen. Die Defakatin war entweder am Wasserbecken im Hause dei' in del' SchlammpfUtze au13erhalb des Hauses lkalisiert. Es ging bestimmte Pfade (Abb.6). Es winselte auf ganz bestimmte vveise, ab und zu sehr lange. Wenn es pendelte, h b es die Hinterbeine abwechselnd an. Schrifttum ANDERSEN, S. (1961): Sumatran Rhincers (Dider-mce1'us sumatmensis) at Cpenhagen Z. Int. Z Yearbk 3,56-57. HANSTROM, B. (196): Djurens Varld. 14. Malm. HEDIGER, H. (195): Wild Animals in Captivity. The Dver Editin, published 1964. RALPH SONNE-HANSEN 21 Kbenhavn (Danemark) Lyngbyvej 5 st. tv.