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Home , Hippopotamus, Pygmy hippopotamus

I 26 BREEDING

The care and breeding of the Pygmy Choeropsis liberiensis in captivity

H. R. STROMAN & L. M. SLAUGHTER National Zoological Park, Washington, DC, USA

GENERAL DESCRIPTION arrived our knowledge of care and breeding had The Choeropsis liberiensis improved to the point where six of her eight off- of is closely related to the spring were raised to maturity. The other two hippopotamus Hippopotamus amphibius but is the lived almost a year. Of the 24 born to this more primitive of the two living . They trio, eight were males and 16 were females. Of were first discovered by Dr Samuel G. Morton in these, nine are still living in around the 1844, but were not actually seen outside Africa world. When the male died in 1955 our initial until 1873, when a young arrived at breeding programme came to an end. Three years Dublin . Dr Hans Schonburgh captured five later the original female died and left the zoo with Pygmy for the noted animal dealer, Carl only caught female acquired in 1940 and Hagenbeck, in 1912 (Crandall, 1964). two of her female offspring, Susan and Millie. Possibly because of their close resemblance and Five years later the National Zoological Park diminutive size these are often mistaken was presented with a young male who reached for baby Nile hippos by the uninformed. The sexual maturity in 1962. In December of that average Pygmy hippo weighs about 272 kg year, with the of his first , a new line of (600 1b) and stands 84 cm (2 ft 8 in) at the breeding was begun. Nineteen calves have been shoulder. As nonsocial animals, they prefer living sired by this male; 12 are still living. in solitary fashion in the rain forests of their The average success was reduced considerably habitats (, Niger, and the by one female who continually gave birth to Coast), and, being nocturnal they deformed young. Three out of four of her calves prefer the tangled thickets of the rainforests, yet were malformed. She was removed from the they do swim when the situation warrants it. breeding programme. Of the 19 young in the At the National Zoological Park the Pygmy latest line, I I were males and eight were females. hippopotamus has been designated a 'vanishing Since 1931, 43 Pygmy hippos have been born animal'. In their native countries they have been at the National Zoological Park of which 21 are ruthlessly hunted for meat and sport and have still living, four are at present at the zoo. The 1940 never been given local protection. The future of female, the 1962 male captured in Liberia, and a the Pygmy hippopotamus almost certainly lies new female acquired in trade represent our present in the hands of zoos and breeding farms around breeding stock. The 1940 female was mature when the world. captured and at the age of 32+ she has ceased breeding and cannot be counted in our future HISTORY OF THE PYGMY HIPPOPOTAMUS AT plans. In the past few years a number of zoos and THE NATIONAL ZOOLOGICAL PARK game farms have transferred females to the Na- In June 1927 the first Pygmy hippo, a male, tional Zoological Park for breeding purposes. Our arrived at the zoo. Two years later the introduc- male has successfully impregnated all of these tion of a female initiated a breeding programme females and this portion of our breeding plan that continues at the present time. The addition will probably continue. of a second female (captured in the wild) added impetus to the breeding programme. The off- CARE OF THE PYGMY HIPPOPOTAMUS spring of the first female (produced over a period Pygmy hippos are easily cared for as it is only of 24 years) totalled 16. Of these, only six lived necessary to house them in a heated building with to maturity. By the time the second female access to a small water tank. The water must be BREEDING

warmed in winter. Because of the defaecating If it becomes necessary to examine or treat one, habits of all hippos, it is necessary to hose their the best method is to use a handling crate which area many times daily. To ease this burden en- is just large enough to allow the hippo sufficient closures should be made of concrete with metal standing room. At each end it should have sliding doors. A waste gutter at the rear of the enclosure doors which should be cut in half, so that the top carries away urine and faeces. Access to a water tank portion can be removed to work through. The approximately 3 x 4.6 x 1.2 m (10 x 15 x 4 ft) deep top crate must be hinged in case it is necessary to is desirable. The tank can be divided by a pipe work from the top, and a number of openings cut fence so that one tank will serve two enclosures. into the sides will ensure proper ventilation if the A great deal of defaecating is done in the water animal is to be held in it for any length of time. so it will probably need to be changed twice daily. Double skids of hardwood with metal runners Pygmy hippos vary in their personal habits; some built under the bottom of the crate will facilitate require more attention than others. dragging it and strengthen the foundation; this is If conditions are very crowded some animals important if the crate is to be moved with a fork- can be kept in the water during the daylight hours lift. and others can use it during the night. Except When it becomes necessary to catch a Pygmy during breeding, two animals should not be hippo, the crate is placed outside the shift door. A placed in the same tank or cage as they will almost number of men then enter the cage, walking invariably fight, causing great damage in a matter behind hand-held sheets of 18 mm (2 in) ply- of seconds. Another major hazard is damage to wood and slowly move the animal toward the , which sometimes break off below the gum shift door. As the hippo becomes cornered, an line causing pain to the animal. Prolonged con- assistant opens the shift door and, in most cases, tact with another aggressive animal results in both the animal, seeking safety from the keepers and animals becoming highly nervous. advancing plywood, will dart through it into the If a Pygmy hippo has access to an outside yard crate. The sliding doors are then dropped and the in favourable weather, it will enjoy a mudhole in animal is ready for treatment or observation. In which to wallow, but the animals should never be such a crate, the hippo can be examined from the allowed to remain outside for long periods in the front, rear, and top. It is also simple to feed, fall when the water and ground begin to chill. In water, and clean the animal in it if necessary. If a general, Pygmy hippos are easily cared for, hippo is to be shipped to another location, the requiring only a large amount of attention to same procedure can be followed and the animal hosing their area and constant observation by moved into a shipping crate at the last moment. their keeper. BREEDING DIET The male hippo should always be kept in a sep- The diet for healthy Pygmy hippos is very simple; arate cage, except when breeding. The use of a a good grade of commercial horse chow or tank with a pipe partition down the centre will pellets and a small amount of alfalfa hay is all that facilitate introductions. The animals are placed is usually required. The quantity depends on the in the tank, one on each side of the pipe partition, individual animal; an average hippo consumes in about 45 cm (18 in) of water. If the water is 3.8 1 (one gal) of commercial horse pellets and deeper, the female will not be able to breathe 1.36 kg (3 Ib) of alfalfa hay daily. The keeper who properly during mating. A keeper should be is familiar with his charges can increase or de- present at all times during the process. If possible, crease feed as the hippo's condition warrants. the partition should have a sliding gate at each Trying to complicate this diet in a healthy end; this allows the hippos a flight pattern tu 'go animal is a waste of timc and money, for hippos around in circles' so to speak and, in the event of have been bred, raised, and maintained on it alone. fighting, enables the keeper to isolate one of the animals as it passes a gate. One animal will almost SHIPPING AND HANDLING always run - normally the male. During this Handling Pygmy hippos manually is almost time the actions of the animals should be care- impossible; they are aggressive and dangerous. fully observed by an experienced keeper. Signs of 128 BREEDING

compatability are deep and audible breathing of level should be no more than 30 cm (12 in) deep. the female, rubbing noses, and standing quietly. If signs of labour are noted while the female is Danger signs are a playful female, or one who in the tank, the keeper should empty it immed- stands and claps her jaws very rapidly. Occas- iately and move the hippo into a clean, dry, ionally a female will mount and ride a male. The bedded cage as soon as possible. This should have male may pay no attention to her advances but closely spaced bars to prevent the calf falling out. tries to play. The female becomes frustrated and If the female's diet is well balanced, no change is soon a fight will begin. necessary during pregnancy. It seems from the records .that the female hippo probably comes into heat every 28 to 30 PARTURITION days. Unfortunately, there is no precise way to tell On 14 January 1968, a swelling of the vulva was if a female is in heat. Close observation and trying noted on the female Pygmy hippo Millie. As we a pair together in a cage is the method we use. knew when she had mated and she was under When both the animals seem receptive, the observation, she was allowed into the water tank male, after some playful actions, mounts the for a swim, and then returned to her cage to female, usually at an angle. The female tries to ensure safety to the expected young. This par- assist by changing her position. When mating does ticular hippo is by a very restless animal. begin, there is very little movement, but the Normally, the walls of her cage are covered with deep breathing of the female is noticeable. Copu- faeces each morning but during the final two or lation usually iast five or six minutes, after which three days of pregnancy, she does not dirty the the male dismounts and tests the female by cage but defaecates only in the water. This has rubbing noses. Both animals then sleep for an been the general rule for all our females. Although hour or so before mating again. Millie showed definite signs of the approaching Although habits vary with different individuals, birth throughout 14 January she did not deliver some pairs mate five or six times in one day, until the next day. Detailed notes were kept by others only once. Whatever happens, they should her keepers and a summary of the last 12 hours be separated at night and introduced in the mom- is as follows: ing for the next few days. If they mate two or I4 JANUARY three days in succession, the female can usually 1830 Lies down with difficulty, gets up be considered to be pregnant. To be sure, how- and defaecates, paces, lies down ever, the female should be placed next to the male 1930 Gets up and defaecates in the separated cage a few days each month for 20-2100 Sleeps two or three months. If she remains aggressive 2130 Gets up, paces, lies down awk- and shows no interest in the male, she has con- wardly ceived. It should be notcd that some females will 2200 Gets up, paces, defaecates, feeds, mate a few months after they have conceived, and defaecates, feeds, paces this plays havoc with expected birth dates and 2230 Feeds, paces, defaecates, feeds, de- sometimes results in a surprise calf. faecates, feeds Pygmy hippos, being naturally round and fat, 2359 Defaecates, lies down, gets up, do not always look pregnant to the observer. In lies down, gets up, lies down again some cases there is a marked protrusion of the vulva, and the teats may swell. The teats never 15 JANUARY hang as in some pregnant animals but they redden 0030 Sleeps and enlarge. In one of our females, the entire area 0100 Gets up, defaecates, lies down around the vulva protruded to such an extent that again, continuously changes posi- the could not lie flat; it may be significant tion that this animal had a breach-birth. 0130 Gets up, stands still, paces, sits, During late pregnancy the female should not lies down, changes position, rolls have access to the water tank at night when there to left side, gets up, defaecates is no one to observe her. Furthermore, when against wall, paces, lies down on allowed in the tank during this time, the water right side BREEDING

0200 Gets up, defaecates, lies down down, lies on side. Very still, eyes again on right side, rolls over from closed, gets up, feet sticking out, side to side, gets up, sits, lies down, head down; eyes closed, crouching stands up, paces position, lies on side, tail wags, Stands, sits, lies down, gets up, feet still out, back to crouching paces, lies down, gets up position, lies on side, tail wags, Gets up, lies down, gets up, defae- feet still out, back to crouching cates, paces, stands quietly, paces, position, lies on side, feet showing lies down on right side, gets up, more, scoots around cage with stands still, sits on rear, gets up, back bent and strains, paces, lies sits, gets up again down, stands up, scoots around and Paces, lies down, gets up, walks to strains, stands still, squats, back to centre of cage and squats. First wall, strains, lies down and strains, contraction takes place, paces lies on side and strains very hard, again, lies down, gets up, twitches feet can clearly be seen, strains hard, tail against bars feet out to hock, scoots around cage Squats again with mouth open, with head up, mouth open, lies lies down, gets up, twitches tail on side, rests, strains hard against bars, lies down, gets up, 0700 Feet back inside, back to wall, squats and strains, membrane strains, feet can be seen again, rubs visible, lies down wall and strains, lies down, gets Gets up and squats, strains, head up, strains, feet showing more, raised with mouth open, paces, rests licks area where she strained, lies 0730 Gets up, scoots around cage, strains, down, gets up, squats and strains, spurt of , gush of water, walking at the same time. Moisture young is expelled. Calf is a male on and around vulva, lies down, weighing 5.7 kg (122Ib) gets up Strains, sits down and strains, gets Birth weights of the newborn calf may vary up, sits down again, sits up strain- from 3.4 to 6.4 kg (74- 14 lb). ing, wags tail, rubs vulva against The measurements of a typical 6.4 kg (14 Ib) wall, strains, strains very hard in a calf were as follows: half standing-half sitting position, lies down, rolls to one side, vulva open and protruding. Still down, Ground to top of hip head on front legs, strains very Ground to shoulder Girth at shoulders hard again, gets up again and still Circumference of forefoot strains, rubs vulva on wall, foot Circumference of neck can be seen protruding Length of ear Paces, foot back inside, rubs against Diameter of eye wall again, stands with rear to Circumference of muzzle wall, half sits and strains, foot visible at vulva again, up again, Because female Pygmy hippos are receptive to a strains, foot showing at vulva male for some months after conceiving, it has again, up again, strains at wall, been difficult to determine the exact gestation foot back inside, stands, paces, period, which is usually reported as 201 to 210 stands with head down, eats hay, days (Walker, 1964). Four matings and the paces in a circle, strains at wall, resultant from different females, however, foot showing again, scoots around have been recorded which cannot be contested. cage 011 rear, lies down, strains very On these occasions, the gestation periods were hard, back to wall, strains, sits 192- 194, 192, 195 and 196 days. BREEDING 130

CARE OF THE YOUNG constipation. We feed calf manna, bananas and Soon after delivery the female is offered a full milk which have been mixed in a blender to a tank of water to swim in as this aids in passing the milk shake consistency. Finely chopped vege- afterbirth. It also permits the keeper to weigh, tables, fruit, and greens are also given. Sweet examine, measure and sex the new calf. It is not feed and pellets can be fed in very small portions, usually too much trouble to separate them, as the but no attempt should be made to put the calf on mother has been out and away from water for these solids too quickly or all at once. A great deal some time and is usually anxious to return to it; of difference will be noted in individual animals she welcomes the chance to drink and swim. We as to the ability to adjust to weaning. Thus, a never have the tank completely full when we three-week old calf suffering from serious mul- begin this procedure, in case the baby slips tiple puncture wounds inflicted by its mother was through the door before we can close it. While the given the weaning diet and began to eat heartily baby is being examined, it is placed in a shallow the same day. In this particular instance, no sign pan of warm water and given a bath. Normally of pining for the parent was noted, and daily he has his first bowel movement at this time. If he weighings showed no loss of weight. On the other does not, gentle massage will be sufficient stimu- hand, some animals suffer from emotional stress lant. The umbilical cord is cut short enough to during weaning, and refuse to eat for several ensure that the animal cannot step on it and the days. During this time they suffer a rapid loss of end is dipped in iodine. weight, and extremely sore feet from continual For about two weeks the calf is separated from pacing in the cage. The best remedy for foot the female daily for its bath and weight check. trouble is a good muddy yard, and the pacing The birth weight should be between 5.5 and usually ceases as time passes. 6.4 kg (12-14 1b) but smaller calves have been It is very easy to feel concern for individual raised successfully. Daily gains normally average calves who are difficult to wean but we owe it to from 0-45-0.7 kg (I -14 lb). the animal to see that it becomes self-sufficient. When nursing the calf, the female lies on her In all cases, it takes only a few weeks for the side and holds her leg in the air to provide head young calf to adjust. room. It is difficult to pinpoint actual nursing times, because the female often lies with her back HAND-REARING to the observer, but we find that the young suckle The female Pygmy hippopotamus, Epsilon, was about every two hours. The baby hippo is born born on 19 February 1964, in a somewhat pre- with very small tusks - about 1.5 mm (,% in) in mature state - weighing 3.3 kg (7t lb) - being length - which grow very rapidly. The calf is only half the average birth weight. By the end of usually mouthing hay at about one week of age, the third day with the mother, the young animal while its mother is eating. had lost 340 g (12 oz) and she was therefore re- It is of the utmost importance that the baby moved on 21 February for hand-rearing. Initially, have a bowel movement at least once a day. If it the young hippopotamus was fed a formula con- does not defaecate while being bathed, or in the sisting of equal portions of evaporated milk and cage, it should be placed in the tank with its water. This mixture was placed in a bottle and mother, as this will normally stimulate action. attempts were made to induce the animal to The water should be about 30 cm (I ft) deep. nurse. These were not completely successful and If for some reason no defaecation is noted for one only 57 g (2 oz) were taken. Routine bathing or two days, every effort should be made to after each feeding attempt was instituted and was induce it. Our most serious difficulties have in- maintained throughout the hand-rearing. Bathing volved constipation in the newborn calf and, in stimulates defaecation and urination and is essen- all cases of this , a veterinarian is consulted. tial for maintaining the skin in a healthy condi- tion. WEANING Since the young hippo attempted to suck the At weaning (at about three months of age) the fingers of the handlers but refused to suck on a calf's diet is very important. Particularly, it nipple, milk was poured into a pan and the fingers should not receive any dry foods that might cause of the keeper were dipped into the milk and BREEDING I3'

placed in her mouth. In this way the animal was 10.5 kg (23 lb) and swam in deep water in the induced to take an additional 113 g (4 02). Four tank. hours later, the fingers of the keeper were again in- Except for a severe cold which was treated serted in the mouth but the pan of milk was during April, she continued to gain weight and placed closer and closer to her muzzle and, by was still maintained on a soft diet. It seems that turning and tipping the pan, she was induced to Pygmy hippos should not be converted to hay and drink from it. A further I 13 g (4 oz) were taken. grain alone until they weigh at least 18 kg (40 lb). Feeding at +hour intervals was continued Grass and green food were added gradually to the throughout the night with an average intake of soft mixture. The recommended diet until a 113 g (4 oz) per feed. This schedule was main- weight of 18 kg (40 lb) is attained is as follows: tained for the first two weeks and by the end of I cup calf manna I banana this time, she was taking 340 g (12 oz) at a feed. I cup evaporated milk I apple Weight gains were maintained at I 13- 170 g I cup water handful of greens (4-6 oz) daily. By 29 February she weighed The ingredients should be mixed in a blender 4.2 kg (10 lb). until they look like cooked oatmeal, and may be On I March the young hippo was constipated. poured on the floor of the cage.

DATE OF DATE OF GESTATION PERIOD MOTHER MATING BABY BIRTH (days]

Millie 12-14 February Pi 26 August 192-194 Susan 10 August Epsilon 19 February 192 Matilda 25 June Delta 7 January 195 Epsilon 23 May Tau 6 December 196

Table I. Gestation periods of four Pygmy Choeropsis liberiens born at the National Zoological Park, Washington.

An enema alleviated the condition and on 2 PRODUCT MENTIONED IN TEXT March, the milk formula was changed to 3 parts Lactinex granula: manufactured by Hynxon, evaporated milk to 2 parts water and I lactinex We~c~ttand Dunning Inc., Baltimore, Maryland 21201, USA. gnnula. On '5 March feeds were given three Albers-Calf Manna: manufactured by Carnation times daily, at 0800, 1200 and 1600 Intake Albers, 5045 Wilshire Boulevard, Los Angeles, at this time was 650 g (23 02) in the morning; California,USA. 227 g (8 oz) at noon; and 650 g (23 oz) in the afternoon. On 26 March the animal weighed 9.7 kg (21 Ib REFERENCE 6 02).,, and on 27 March she was offered. in addi- tion to her ration, pieces of bread soaked in L. S. (19~4).The management of wild nrammals in captivity. Chicago and London: University milk. This diet was accepted and was maintained of Chicago Press. until 30 March when oIle cup of beet pulp WALKER, E. P. (1964). Mammals ofrhe World. Balti- added to the ration. The animal now weighed more: Johns Hopkins Press.