Two Camel-like Wild Species (the Giraffe and the Okapi

[د. علي سعد محمد]

Summary:
The giraffe (Giraffa camelopardalis) and the okapi (Okapia johnstoni) are two wild ungulates that look and behave like camels in many aspects. They tolerate to be off water for long periods.
The dentition of the giraffe is very close to that of the camel. The dental formula of the latter being; 1/3: 1/1: 3/2: 3/3 while that of the former is 0/3: 0/0: 3/3: 3/3.
The giraffe makes use of its long prehensile tongue for browsing tree leaves, whereas the camel utilizes the structural modifaction of its upper lip for browsing tree tops. The giraffe, however, differs from the camel by having two skin-covered horns in both sexes. There is no gall bladder in the giraffe as it is the case with the camel.
The okapi is similar to the giraffe, except for the short neck of okapi and the presence of skin-covered horns in the male only.
The giraffe lives in open forests of low rainfall at sahara edges like the camel, but the okapi, on the other hand, is a dweller of thick rain forests in the Congo.
All the three species, camel, giraffe and okapi, are similar ruminants.
The giraffe is now disappearing from its natural habitats in Northern Sudan at an alarming rate. It is recommended that rehabilitation and reintroduction of the giraffe into its natural ranges should receive prime consideration as most of the camelidae species are threatened by extinction. Such animal species, being adapted to adverse and hard environmental conditions, can avail an important resource potential for gene banks, molecular biology and genetic engineering in the future.
Introduction :-
As the camel is representing the genus Camelus in the domestic stock, there are some wild animal species that resemble the camel in a way or another; of these are the giraffe (Giraffa camelopardalis) and the okapi (Okabia johnstoni). Both species belong to the order Artiodactyla “even-toed ungulates'' and are both ruminants and browsers. In this study the main characteristics which they share with camels will be discussed.
1-The giraffe:-
It’s the tallest mammal living in the present world, as an African dweller unmistakable for its very long legs and neck (Guggisberg,1969). the average weight of giraffe is 875 kg. It stands about 5.50 m from fore hooves to the tips of the horns. There are two horns in the male and the female (different from domestic camel) (Brocklehust, 1913).the shoulder heights 2.90 m and 2.45 m for male and female, respectively (Innes,1969). The giraffe has a prehensile tongue and long narrow muzzle. Giraffes drink every few days if water is available. There is considerable controversy on the amount of water required by the giraffe. As observed in zoological gardens, it was reported that a giraffe drinks 10 gallons a day on the average when the temperature is about 32˚ C, while it drinks 2.64 gallons in cool weather (Faster, 1966). It was also stated that giraffes, similar to camels, can go without water for long distances.
The dental structure of the giraffe is composed of three premolars and three molars on each side of the upper jaw. The lower jaw has three incisors, one canine, three premolars and three molars with a dental formula as 0/3:0/1:3/3:3/3 totaling 32 teeth. The grinding teeth are of the low-crowned type, as a characteristic of all browsers, again similar to camels. The vertebral column of the giraffe consists of 7 cervical,14 thoracic, 5 lumbar, 3-4 sacral and 17-20 caudal vertebrae. The hide is very tough and of 2.54 cm thick. There is a brush- like mane extending from the back of the head to the base of the neck, the tail is 76.2 cm tall ending in a tuft of long wiry hairs. Some interesting anatomical and physiological arrangements worth to be mentioned. Giraffe neck height would make blood flow to the head very difficult or even impossible but this problem has been overcomed by the presence of special valves that serve to regulate arterial blood flow to the head (Arambourg,1964). Pulse is around 66 per minute, and the animal breathes about 11 times a minute. The 2-4 mammae are in the inguinal position. The gall bladder is only in the early faetal stages but later disappears at the time of birth, similar to the adult camel.
The normal gait is of the type of pacing, in which both limbs on one side move forward, almost in unison .
The long neck helps the animal to browse at tree canopies, but when it wants to drink or to nibble at a herbaceous plant or to pick a mouthful of salty soil, it has to straddle its forelegs apart .
The giraffe, in South West Africa, mate in the rainy season. According to observation in zoological gardens the gestation period varies from 420 to 468 days, differing from the camel which has a range of 360-390 days.
The newly born calf which has an average height of 130 cm and weighs between 46 and 70 kg. Usually struggles to lift its feet in 30 minutes to one hour after birth.
2-The okapi:-
The okapi is a browser that lives in the rain forests of the Congo. It uses its tongue in licking at its skin and used for grooming the coat. Body colour varies from darkest blackish-brown to brilliant golden red. It has an excellent sense of hearing. The cervical vertebrae are seven, resembling those of the camel. There are 14 thoracic vertebrae, 5 the lumbar, and 5 and 13-14 sacral and caudal vertebrae, respectively. The dentition is similar to that of the giraffe .
The adult female stands 148.75 cm at the shoulder and 217.5 cm long of which 35 cm represent the tail, not including the fairly short terminal tuft. The male has two short skin-covered horns, conical in shape and sloping backwards, which arise from the frontal bones.
The distribution of okapi extends from the Semiliki River in the east to the Mongola and Ubangi River in the west. Okapi is a browser, feeding on leaves and shoots, perhaps also on fruit. The animal browses on more than thirty plants, of these plants are the following species:-
A Rubiacea, Bandia conglana and several Euphorbiacea are thought to be among its favourites (Kirby,1895).
The gestation period of okapi varies between 426 and 457days. The female eats the faetal membranes. The calf staggers to its feet in 40 minutes after birth. The baby measures on its first day 85 cm at the shoulder and weights 21.7 kg.
As for as the giraffe is concerned, it has been noticed that the animal has disappeared from most of its natural habitats in Northern Sudan. The last giraffe seen in the Dinder National Park was in the early nineties of the last century. It is recommended that there is an urgent need to rehabilitate the giraffe natural environments and introducing the species to start regaining its past natural distribution. The giraffe and relative species are adapted to living in harsh and adverse environmental conditions and thus, playing a great role in animal biodiversity. Table 1 shows the characteristic of camels, giraffe and okabi.
References:
Arambourg, C. (1964). Continental Vertebrate Faunas of the Tertiary of Northern Africa. In: Africa Ecology and Human Evaluation. London.
Brocklehurst, (1931). Game Animals of Sudan. London.
Faster, J.B (1966): Giraffe of Nairobi National Park. Home Range, Sex Ratios, the Hard and Food: E.A. Wildlife Journal. Vol. IV.
Guggisberg, C.A.W (1969). The World of Animals: The Giraffe. Arthur Barker Limited, London.
Innes, A.C (1969). The Behaviour of the Giraffe (Giraffa camelopardalis) in Eastern Transvaal. Proc. Zool. Soc. London. (cited from Guggisberg).
Kirby, F. Vaughan (1969). In Haunts of Wild Game. London, 1895. Cited from Guggisberg,1969.
Moberly, C.T Astley (1963). The Game Animals of Southern Africa. Johannesburg. (cited from Guggisberg ,1969).
Table 1. Characteristics of camels.
Characteristic Camel Giraffe Okabi
Distribution Africa Africa Africa
Habitat Savanna, desert, semi-desert Savanna, semi-desert. Rain forests
Feeding habits Browser Browser Browser
Type of digestive tract Ruminant Ruminant Ruminant
Hump Present Not present Not present
Skin covered horns Not present Present in both sexes Present in the male
Gall bladder Not present Not present Not present
Legs Long Long Medium length
Neck Long Long Short
Gestation period 360-390 dm. 426-460 dm. 426-457dm.
Anatomical peculiarities Fissured upper lip Prehensile tongue Prehensile tongue