Susceptibility to Cold in Captive Giraffe (Giraffa camelopardalis)
American Association of Zoo Veterinarians Conference 1999
Marcus Clauss1, MSc; Wm. Kirk Suedmeyer2, DVM; Edmund J. Flach3, MA, MSc, VetMB, CertZooMed, MRCVS
1Institute of Zoo Biology and Wildlife Research, Berlin, Germany; 2Kansas City Zoological Gardens, Kansas City, MO, USA; 3Veterinary Science Unit, Institute of Zoology, Whipsnade Wild Animal Park, Dunstable, Beds., United Kingdom


There are numerous reports of dead captive giraffe with no discernible cause of death except serous atrophy of adipose tissues. The term “peracute mortality syndrome” has been utilized to describe this finding.11 Although the common linolenic acid deficient status of captive animals might contribute to the problem;5 there must be another triggering mechanism. As cold stress is a well-known inducer of lipolysis, the probability of captive giraffe being cold-stressed was examined by a literature search.

In the wild, giraffe are renowned for their ability to withstand extreme heat and radiation.21 In captivity, they rarely seek shade even on hot days.7 Two hypotheses explaining this phenomenon exist: The unusual body shape of the giraffe is believed to maximize heat dissipating surface relative to volume,3 and an obligatory heterothermia allows giraffe to save energy for body temperature (BT) regulation by simply allowing body temperature to rise along with ambient temperature.17,18 The correlation found between ambient and body temperature is demonstrated in Fig. 1. In contrast, the zoo medicine literature gives a constant normal BT of captive giraffe of about 37.5–38.8°C.20

Figure 1. Correlation of ambient temperature and rectal temperature in three giraffe


While these adaptations allow giraffe to withstand their share of heat, in theory, the same adaptations make them especially susceptible to cold. If they have a comparatively greater heat-dissipating surface, any circumstance that increases heat convection (e.g., wind or humidity) should have a more pronounced effect on them. If they can depend upon ambient temperature to maintain their BT, and allow it to decrease with nighttime temperatures, any condition that forces them to keep their BT elevated against colder temperatures should impose an additional energetic cost on them-possibly to the extent that cannot be compensated. For free-ranging giraffe, high mortalities have been reported after a period of exceptionally cold and wet weather.29 Gastrointestinal capacity and insufficient diets limit the ability to compensate for the energy demands during these periods.

With prolonged cold exposure, blood glucose (Glc), phosphorus (P) and thyroid hormones (TH) should be increased, while calcium (Ca) and magnesium (Mg) should be decreased.24,26 In a state of prolonged hyperthyroidism, as might be induced by constant cold stress, leukocytosis, lymphopenia, hyperglycemia and hyperphosphatemia can develop.22 Blood values related to the energy status of the animal such as Glc and TH should be related to basal metabolic rate; such a relation has been demonstrated for Glc.28

Selected blood values from free-ranging and captive giraffe are presented in Table 1. In general, captive giraffe sampled appear to have a leukocytosis, lymphopenia, hypocalcemia, hyperglycemia, and hyperphosphatemia. While Glc levels may increase due to handling stress, it is debatable whether these consistent high values can be explained by excitement alone. Mg values are generally unchanged, but the sample size for this mineral was extremely small (n=3). In theory, giraffe showing signs of peracute mortality syndrome might suffer from electrolyte imbalances.

Table 1. Selected blood values in cattle,12 wild9,19 and captive giraffe;4,15,23 ranges for captive giraffe are the range of means from the different sources



Wild giraffe

Captive giraffe

WBC × 109




Lymph %




Ca (mmol/L)




P (mmol/L)




Mg (mmol/L)




Glu (mmol/L)




Glu (mg/dl)





A deficiency in linolenic acid, as has been reported for captive giraffe6 could, in theory, contribute to an increase in metabolic rate and diminished adipose tissue stores,13 lymphoid depletion,10 a decrease in both insulin responsiveness and insulin secretion, and a disturbance of myocardial Ca homeostasis.1 A zinc deficiency could, in theory, contribute to a leukocytosis and a lymphopenia,8 and a decrease in adipose tissue stores.14 Both deficiencies should manifest themselves in skin lesions, which have rarely been reported in captive giraffe.


While precise studies are lacking, reported data confirms the hypothesis that captive giraffe should be prone to cold stress. In eland (Tragelaphus oryx), another browsing ruminant with body temperature regulation similar to that of giraffe,27 two cases of death related to stressful events revealed serous atrophy of fat as the only necropsy finding.25 These appear to be the only cases of “peracute mortality” in another ungulate species to date.

Recommendations for indoor housing temperatures for giraffe range from 13–16°C2 to 21–22°C.20 These temperatures are below or close to the ambient temperature that led to minimal BT in free-ranging giraffe.18 A consistent recommendation is that giraffe should not be housed outdoors if temperatures are below 10°C.20 In light of the high incidence of peracute mortality syndrome,16 and its possible link to cold stress, these husbandry guidelines might have to be re-evaluated.

A survey of peracute mortality syndrome related to temperature management and housing latitude is currently being conducted. Fatty acid evaluations are continuing in captive giraffe.


The authors would like to thank the staff at the Whipsnade Wild Animal Park, England, and the Kansas City Zoological Gardens giraffe management staff, for conditioning efforts with their giraffe. In addition, a special thanks to Dr. Murray Fowler, whose insight into the initial syndrome, and his contributions to the field of zoological medicine are greatly appreciated.

Literature Cited

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2.  Benbow, G. 1988. Management of giraffe. Proc. Symp. Assoc. British Wild Anim. Keepers and Marwell Zool. Soc. ABWAK, Bristol, England, 74–78.

3.  Brownlee, A. 1963. Evolution in giraffe. Nature. 200:1022.

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15.  I.S.I.S. Physiological reference values. July 1998. (VIN editor: URL was inaccessible as of 03/10/2021).

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Speaker Information
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Marcus Clauss, MSc
Institute of Zoo Biology and Wildlife Research
Berlin, Germany

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