\9T72 io8 BREEDING times I observed ample urination of clear fluid The baby is obviously gaining weight and, after the mother had cleaned the perineal area barring unforseen events, I am confident that with her tongue, and on the fifth day I noticed a Mumbi will continue to care adequately for her yellow-coloured stool denoting passage of milk offspring, whom we have named Kumba. through the intestinal tract.

Notes on the behaviour and breeding of pacaranas Dinomys branickii in captivity L. R. COLLINS & J. F. EISENBERG National Zoological Park, Washington, DC, USA

INTRODUCTION tion. Although they were compatible and were The pacarana Dinomys branickii is a large cavio- maintained together in large quarters for four morph inhabiting the valleys and lower months, no sexual behaviour was observed be- slopes of the in , Ecuador, Peru, tween them. Female 1 died on 8 June 1968; male Brazil, and Bolivia (Walker, 1964). Little is known 1 lived until 23 August 1968. of the behaviour of free-living specimens (Tate, An additional female ($2) was acquired as an 1931; Sanborn, 1931), but a few accounts have immature on 1 March 1968. She was been published on their behaviour and main- housed with male 1 after the first female's death, tenance in captivity (Mohr, 1937; Crandall, but again no sexual activity was observed. 1964). Gravid females have been taken in Feb- Female 2 was then transferred to the Research ruary and May. Females have four mammae, and Division and an intended mate (animals were housed in a metal- captive animals are primarily active after dark. lined enclosure measuring 3*6X i-oX 12 m (12X Although several zoos have maintained this 3^X4 ft). This was subdivided into four equal- , its breeding in captivity has been re- sized compartments by the addition of metal corded only recently. C. Schmidt (pers. comm.) panels with sliding access doors. Each animal had reports two successful matings at Zurich Zoo. access to two compartments except during breed- The first gravid female died before parturition, ing encounters when both animals could get into but the most recently-mated female was still alive all four compartments. Stout branches were pro- on 10 January 1971. A female at San Antonio vided for climbing, and wood shavings were laid Zoo gave birth to two young on 8 January 1970 on the floor. after arriving gravid from the wild. Pacaranas Copulation was observed between female 2 and have been investigated since 12 February 1968 male 2 on 24 July 1968, but unfortunately the by personnel of the Research Division of the female died on 7 August 1968. An autopsy revealed National Zoological Park. myocarditis as the cause of death. It is interesting that, although the female was receptive to the BREEDING HISTORY AND MAINTENANCE OF male's mating attempts, the animals could not be COLLECTION housed together for extended periods without Five Dinomys branickii have been maintained in fighting. The same situation later prevailed our collection. The first pair of specimens, between male 2 and female 3. acquired on 7 February 1968, consisted of a large Since male 2 showed promise of being a poten- female (? 1) and a smaller male (rodents leads us to believe that it They may adopt a variety of postures when may be from four to six weeks. Hence, conception sleeping, including resting on the heels and the may have taken place one or two months later than base of the tail while sitting in an upright posi- 13 April. For this reason, gestation could not be tion with the head drooping slightly on the chest; determined exactly but it is certainly not more than lying on one side at full length; or lying on the 283 days nor less than 223. back with the ventrum fully exposed. Sleeping in Both animals receive a diet consisting of corn- the first position, that is, while sitting, is especially on-the-cob, kale, white and sweet potatoes, common when the animal rests in the crotch of a carrots, apples, oranges, bananas, grapes, a tree or utilises sleeping shelves. Nest-building variety of breads, a seed and grain mixture, behaviour by pregnant or parturient females was monkey biscuits and pelleted alfalfa. Fresh or never observed. fresh-frozen corn-on-the-cob is an excellent Typically the animals feed while upright, hold- dietary component when weight gain is desired. ing the food with the forepaws. They are quite This item is usually the first to be eaten when the selective in their feeding habits as has been noted daily feed is placed in the enclosure. It also serves in the previous section. No caching behaviour as an excellent medium for administering liquid could be detected on the part of our specimens. multi-vitamin drops or medication, and the speci- The animals have rather complicated self- mens receive one cob daily unless weight gain is grooming patterns. A specimen will alternatively desired. stroke the length of its face with the inner part of its wrists, first the right side, then the left. It BEHAVIOUR PATTERNS AND ASSOCIATION may pause to wipe the wrists on the inside of the VOCALISATIONS lips at the conclusion of the down stroke, repeat- ing the arm or wrist stroke on the face. After General maintenance behaviour: The animals several wipes on the face, the animal will begin move about by means of a crossed extension to brush down and backward along its flanks with pattern with a forefront in synchrony with the the wrists, pausing to scratch with its fore-claws BREEDING under an arm or between the legs. It appears that related to visual display functions but, rather, are the washing pattern involves wiping the wrists on movements accompanying the various positions the side of either cheeks, brushing down over taken up during combat. Olfactory signals are the face and flanks with the wrists, followed by probably involved in marking behaviour, naso- delicate scratching movements. The claws of the genital investigation, and naso-nasal contact. forepaws may be used to scratch around the eyes General odours emanating from a conspecific and ears. The hind foot is also used to scratch the are probably perceived during all close contact cheeks and face. interactions and, indeed, it is difficult to separate A pacarana will generally urinate and defaecate tactile communication from olfactory communica- at a single locus in its cage, urine and faeces gen- tion during such interaction. Hence, rather than erally being deposited on the same spot. When two separate these two forms, they will be con- animals are housed together, they will use a com- sidered together when we discuss the various mon toileting spot within the cage. This behaviour postures and movements in the next subsection. suggests that urine and faeces may have a marking Pacaranas produce seven clearly defined sound function; however, several other behaviour types. Two of these (tooth chattering and forefeet patterns may be important in marking. When stamping) are mechanical disturbances produced moving about its home cage, males are frequently by movements of the teeth or forepaws. The re- observed to rub their cheeks on branches or maining five sound types are produced by expel- other artifacts. In addition to the cheek-rubbing, ling air through the glottis and pharynx. males secrete a whitish fluid from the glands sur- Tooth-chatter: a rapid clicking of the incisor rounding the eye. Production of this secretion and teeth, generally seen during a threat context. its deposition in various parts of the cage will be Forefeet stamping: a slow rhythmic alternate discussed in the next section. Gnawing within the patting of the forefeet, usually seen in a thwarting cage is generally performed at the same points context. over and over again. The animal, as it explores in Hiss: an unvoiced expiration often following the evening, will be observed to approach various staccato whimpering when interaction with a protuberances in the cage, sniffing carefully and conspecific becomes intense or when the staccato pausing to nibble only at the spots that have been whimpering is uttered as a warning that goes gnawed previously. This suggests that some unheeded. This vocalisation may be accompanied chemical trace is present - such as a saliva deposit by a rush at an adversary. or perhaps scrapings from the incisor teeth - Grunt: a seriesjof soft sounds uttered approximately which induces the gnawing response. Alterna- one per second; heard in a defensive context. tively, the 'cue to gnaw' may be the uneven sur- Growl: a continuous emission approximating to a face left by the previous gnawing attempts. Since low rumble. This may be heard in a mild threat the animals do not attempt to gnaw out of the context and has been noted in males only so far. cage, one suspects that gnawing at selected points Staccato whimper: a high-pitched vocalisation within the home range could serve a marking with several subtypes. It may be released by con- function. tact with a conspecific or may be produced whe nan individual is permitted to enter a conspecific's Behaviours observed in a social context. enclosure. It increases in intensity and duration as Communication mechanisms: The small eye interaction with a conspecific becomes more fre- of the pacarana suggests that vision is not one quent. It may be uttered as a submissive sound of the more important means of gaining informa- during initial encounters and at its highest in- tion about its environment or the state of a tensity form may precede an actual threat or rush. conspecific. In fact, one of our specimens had Two-syllable grunt: this sound has been pro- cataracts in both eyes and seemed in no way duced only by juveniles, generally when following inconvenienced by its inability to see clearly. an adult. It is a soft note, grunt-like but defi- Indeed, this specimen appeared to be able to orien- nitely di-syllabic, repeated at intervals of about tate toward conspecifics and respond using ten seconds. It appears to function as a contact olfactory, auditory and tactile cues alone; hence, note, permitting a juvenile to notify an adult of many of the movement patterns are probably not its presence. BREEDING

The hiss, growl, and staccato whimper are the the eyelids and drains copiously from the external most common vocalisations heard in male-female nares. When the male pauses to sniff an object in encounters. the environment, bobbing the head up and down slightly, drops of the secretion are applied to the Defensive and offensive postures: Upon being substrate. The male will attempt to place secre- disturbed the pacarana either attempts to move tions high up on a vertical object, such as a tree away or assumes an upright stance and begins trunk, by stretching to his greatest possible vocalising. At the time of assuming the upright height in a bipedal stance with the forepaws position, the fur is erected and the animal may placed against the surface to be marked. The de- tooth-chatter. Alternatively, it may hiss, and posited fluid dries quickly to a yellow-white follow the hiss with a series of grunts repeated residue which could possibly serve as an effective with about one-second intervals between indi- visual mark on a dark surface such as bark of vidual grunts or, at high intensity, the grunts may certain tree trunks. Females have been noted to fuse into a continuous growl or deep rumble. sniff the marked loci on numerous occasions. On Full threat display involves approaching while one occasion a female in our group was observed holding the mouth half open with the head tilted to secrete copiously from her eyes at a time when at a slight angle to the horizontal. The animal she was not with the male, but she was never continues to approach and, when quite close to the observed to mark with the fluid. offending object, rears up on its hind legs and Naso-nasal contact: the animals come together continues to walk in a bipedal shuffle. The fore- and touch noses either while both animals are in a paws are held slightly in front of the body but quadrupedal stance or while one is standing on relaxed at the wrists. The mouth is held half its hind legs. open with the yellow incisors exposed. The head Naso-anal contact: one animal sniffs at the anal is lifted higher and higher so that a horizontal region of the second, again either while both line drawn from the muzzle to the base of the skull animals are in a quadrupedal stance or while one would be parallel to a line drawn through the is in a bipedal stance. Mutual naso-anal or naso- long axis of the body. Upon approaching the genital contact is termed circling. object to be threatened, a male may exhibit an Naso-genital contact: a variant of the former con- erect penis. This behaviour is accompanied by figuration, this occurs when both animals are on urination (en-urination) in a number of different all-fours or when one is on its hind legs. Fre- caviomorph species, including Dolichotis pata- quently, the female, when receptive, will arch her gonum, Erethizon dorsatum, Cuniculus , tail dorsally. Dasyprocta and Myoprocta pratti (Kleiman, Upright confrontation and grappling: one animal 1969 and In press) but we have not seen enurina- assumes an upright bipedal stance and faces the tion in male pacaranas during such an upright other, and this may be a prelude to threat vocali- threat posture. sation. Balance is usually assisted by placing the forepaws on the conspecific's shoulders or upper Contact-promoting behaviour: These be- fore limbs. Should the partner also assume an haviour patterns were observed in the initial upright position, a mutual upright configuration phases of male-female encounters, some of which occurs. If the animals do not threaten one another, led to sexual behaviour and mating, which are they may nibble each other's necks; and if both are discussed in the following section. Contact- upright, they may entangle their forelimbs, and promoting behaviour allows two individuals to push and spar at one another with the forepaws. become familiar with one another, and involves This latter pattern has been termed grappling. the exchange of chemical and tactile information Incisor coupling: this configuration may develop coupled with various aspects of threat behaviour. out of the grappling posture. Conspecifics main- Marking: during an encounter the male will often tain their balance by placing their forepaws on begin to mark with an exudate produced by each other's shoulders or upper forelimbs. The glands associated with the mucous membranes of head is then tilted to the right or left and the the eye sockets. The marking secretion (a milky mouth is opened. The incisors are passed through fluid) is conspicuous, because it fills the rims of the opening made by the partner's mouth and BREEDING coupled together with both animals' incisors Mounting: the male approaches the female and being closed behind those of the partner. Touch- bites her neck. He then straddles her from the ing has also been seen to occur but, in this case, rear, mounting her while clasping his forelimbs the incisors are not coupled together but merely tightly about her abdomen just anterior to the brought into contact on their frontal surfaces. hips. If the female is receptive, intromission and Head-over, head-under: the animals 'face each thrusting follow. A female may make several other in a quadrupedal stance. The male then attempts to mount the male, usually by placing places his chin over the female's snout, rubbing her forepaws on his back and, in one instance, his chin on her rostrum. actually climbing on his back. When the female Head toss and pivot: this is related to threat as attempts to mount, she frequently does so from described in the previous section and, indeed, is a the side of the male rather than from the rear. variant of the upright threat. It involves a quad- Intromissions are of brief duration, lasting less rupedal approach to the conspecific whereupon than 20 seconds. Several intromissions may pre- the animal will hesitate and check its forward cede ejaculation. Three bouts of intromissions motion by rising on its hind legs and tossing its have been noted during one io-minute period. head to one side while pivoting, either landing on The male appears to ejaculate once only and thus all fours facing at an angle to the partner or re- resembles other caviomorph rodents studied to maining bipedal but facing slightly to one side. date (Kleiman, In press). When performed mutually and bipedally, it has the appearance of a dance and has been termed the PROTOCOL OF MATING BEHAVIOUR ritualistic dance. A total of 15 observed encounters were carried out Ritualistic dance: while both animals are in an involving male 2 and female 3, and three observed upright posture, they will bounce and pivot on encounters between male 2 and female 2. Copula- their hind limbs, pawing the air with their fore tion was observed twice between male 2 and female limbs while their heads are pointed vertically. 3 and once between male 2 and female 2. A 38- The male shows an erect penis at this time but minute encounter between male 2 and female 3 has never been observed to urinate on the female. on 24 July 1968 proceeded as follows: Grooming: during grappling, or during naso-anal 0907: Naso-nasal contact followed immediately or naso-genital investigation, the investigating by upright confrontation posture of both animals animal may lick at the partner's genital area, with grappling and pushing flanks, shoulder or nape. If the interaction be- 2 retreats (BREAK) naso-nasal contact comes agonistic in character, licking may grade (J applies neck bite while attempting mount into nibbling and then into nipping which may $ assumes upright posture induce actual fighting. cJ retreats (BREAK) naso-anal contact ($ to

(J attempts mount noticed that the female was becoming increasingly naso-genital contact (

DESCRIPTION OF FULL-TERM UTERINE this respect its behaviour resembles that described YOUNG for other caviomorphs. The young were precocial, and at the time of their The large size, increased weight, shorter tail, removal from the uterus were fully furred with and slow movements conform to patterns and open eyes and ears. Each had well-developed trends seen in some of the larger cursorial cavio- upper and lower incisors. Measurements of both morphs, such as the capybara Hydrochoerus, are given in Table i. agouti Dasyprocta, and paca Cuniculus. However, Dinomys is not cursorial but is rather slow and DISCUSSION AND SUMMARY ambling in its movements, and in this respect, Dinomys branickii will breed in captivity pro- resembles the North American porcupine Ereth- vided that the animals are housed in spacious izon. It is also similar to Erethizon in that it is an enclosures. Even though individuals may show able climber, a previously unreported ability. great tolerance for one another, separation of an The marking behaviour of Dinomys, involving adult male and female with subsequent simul- secretions from the glands associated with the taneous introduction at intervals of approxi- orbit, which drain into the nasal cavity, appears to mately five to ten days helps to establish a com- be unique. patible relationship and perhaps induces mating activity. These rodents exhibit an extremely long ACKNOWLEDGEMENTS gestation period which, though we have not estab- Photography by Dr C. Wemmer and Mr E. Maliniak lished its length with certainty, is between 223 greatly aided the study. We are also indebted to Miss and 283 days. This would make it the longest R. Aulisio for her observations on several controlled encounters between pairs of pacaranas. Miss Aulisio's recorded for a rodent. Its length suggests that work was supported by an undergraduate research females produce only one litter per year; hence, fellowship from the Smithsonian Institution's Office their recruitment rate in the wild is very low. The of Academic Programs. young are extremely precocial at birth, as indi- cated by the condition of the foetuses removed REFERENCES from our female and by observations at San CRANDALL, L. s. (1964). Management of mild Antonio Zoo, but this is in accordance with in captivity. Chicago and London: The University of observations recorded for other caviomorph Chicago Press. rodents (Kleiman, 1969; Smythe, 1970). KLEIMAN, D. G. (1969). The reproductive behaviour of the green , Myoprocta pratti. Ph.D. disserta- The behaviour patterns of Dinomys show broad tion, University of London. similarities with those recorded for other cavio- KLEIMAN, D. G. (in press). The courtship and copu- morph rodents (Klieman, 1969; Maliniak & latory behaviour of the , Myoprocta Eisenberg, 1971; Smythe, 1970). Dinomys shows, pratti. Z. Tierpsychol. MALINIAK, E. & EISENBERG, J. F. (1971). The breed- in some respects, certain similarities in behaviour ing of Proechimys semispinosus in captivity. Int. Zoo Yb. to Proechimys - which might be considered to be a 11:93-98. relatively unspecialised caviomorph rodent. Thus, MOHR, E. (1937). Vom Pacarana {Dinomys branickii a staccato whimper indicative of submission may Peters). Zool. Gart., Lpz. 9: 204-209. be emitted by either sex during the initial phases SANBORN, c. c. (1931). Notes on Dinomys. Publs. FieldMus. Nat. Hist. 18: 148-163. of an encounter which is not agonistic in its SMYTHE, N. (1970). The behaviour and ecology of the nature. An upright posture is assumed by both agouti (Dasyprocta punctata) and related species on males and females indicating threat, but, on the Barro Colorado Island, Panama. Ph.D. dissertation, other hand, enurination has not been recorded University of Maryland. TATE, G. H. H. (1931). Random observations on South for Dinomys or Proechimys. However, unlike American mammals, jf. . 10: 176-178. Proechimys, Dinomys has a relatively brief mount WALKER, E. P. (1964). Mammals of the world. Balti- duration (Maliniak & Eisenberg, 1971), and in more: Johns Hopkins Press.