Stéphane Ostrowski

Forty-five wildcats (Felis silvestris), 17 sand cats (Felis margarita), and 17 feral domestic cats were captured in central west Saudi Arabia, between May 1998 and April 2000, with the aim to assess their exposure to feline immunodeficiency virus/puma lentivirus (FIV/PLV), feline leukaemia virus (FeLV), feline herpesvirus (FHV-1), feline calicivirus (FCV), feline coronavirus (FCoV), and feline panleukopenia virus (FPLV). Serologic prevalence in wildcats, sand cats, and feral domestic cats were respectively: 6%, 0%, 8% for FIV/PLV; 3%, 8%, 0% for FeLV; 5%, 0%, 15% for FHV-1; 25%, 0%, 39% for FCV; 10%, 0%, 0% for FCoV; and 5%, 0%, 8% for FPLV. We recorded the first case of FeLV antigenemia in a wild sand cat. Positive results to FIV/PLV in wildcats and feral cats confirmed the occurrence of a feline lentivirus in the sampled population.

SUMMARY To test the idea that large, free-living, desert ungulates use heterothermy to reduce water loss, we measured core body temperature (T_b) of six free-ranging, adult Arabian oryx (Oryx leucoryx) during 2 years in the arid desert of west-central Saudi Arabia. We report the first case of heterothermy in a free-living ruminant in a desert environment: T_b varied by 4.1±1.7°C day^–1 during summer (June to September) and by 1.5±0.6°C day ^–1 during winter (November to March). Over both seasons, mean T_b was 38.4±1.3°C. During the day in both summer and winter, T_b increased continually, suggesting that oryx store heat instead of dissipating it by evaporation, whereas at night T_b decreased. The minimum T_b was lower in summer (36.5±1.16°C) than in winter (37.5±0.51°C) despite the fact that the temperature gradient between T_b and air temperature (T_a) was larger and solar radiation was lower in winter. Throughout the year, daily variation in T_b appeared to reflect thermal load (T_a,max–T_a,min) rather than an endogenous rhythm. Behavioural thermoregulation was used by oryx to cope with thermal stress during summer: animals lay down in shade in the morning shortly before T_a exceeded T_b and remained there until evening when T_b–T_a became positive. The use of heterothermy by oryx resulted in storage ofandwould672.4 kJ day^–1 animal^–1258.6 kJ day^–1 animal^–1in winter, if heat storage is based on calculations involving mean T_b. Todissipaterequirethisheatin summerby evaporation0.28 litres H₂O day^–1 animal^–1and0.11 litres H₂O day^–1 animal^–1 in summer and winter, respectively. Without heat storage in summer, we estimated that oryx would have to increase their water intake by 19%, a requirement that would be difficult to meet in their desert environment. If heat storage was calculated based on the daily change in T_b rather than on heat storage above mean T_b then we estimated that oryx saved 0.538 litres H₂O day^–1 animal^–1 during summer.

Scattered populations of Rüppell's foxes (Vulpes rueppelli) occur across the deserts of northern Africa and Arabia. Little is known about the biology of these canids, especially the physiological mechanisms that contribute to their ability to live in such harsh environments. For individuals from Saudi Arabia, we tested the hypotheses that Rüppell's foxes have a reduced basal metabolic rate and total evaporative water loss (TEWL), parameters measured in the laboratory, and a reduced field metabolic rate (FMR) and water flux when free-living. Under basal conditions in the laboratory, males, which averaged 1,858 g in body mass, had an oxygen consumption of 914.9 mL O(2)/h, whereas females, which weighed on average 1,233 g, consumed 682.9 mL O(2)/h; rates of oxygen consumption translated to 441.4 kJ/d and 329.4 kJ/d, respectively. TEWL averaged 52.6 g H(2)O/d for males and 47.5 g H(2)O/d for females. We found no evidence that basal metabolism is reduced in Rüppell's foxes, but their TEWL was remarkably low: 50.9% of allometric prediction for males and 64.5% for females. In the wild during winter, males expended energy at a rate of 1,306.5 kJ/d, whereas females had an expenditure of 722.8 kJ/d. Analysis of covariance with FMR as the dependent variable, sex as a fixed factor, and body mass as a covariate showed no statistical difference in FMR between sexes. Water flux did not differ significantly between sexes and averaged 123 mL H(2)O/d, a value 30% lower than the kit fox from the deserts of southwestern North America. FMR was positively related to nocturnal activity levels as FMR (kJ/d) = -2,900.1+55.5 (% of time moving). The water content of prey items varied between 1.9 and 4.1 g H(2)O/g dry matter consumed. Based on these values and knowledge of their diet, we calculated that foxes captured about one rodent and a variety of anthropods per night of foraging.

We measured water-influx rate during the hot summer in free-ranging adult Arabian oryxes (Oryx leucoryx) in Mahazat as-Sayd, a 2,244-km² protected area in west-central Saudi Arabia. Oryxes obtained 2,294 ml/day of water in their food and from oxidative water, the latter amounting to 14.2% of total water influx. For ungulates living in hot environments, we constructed an allometric curve: log(water-influx rate [liters/day]) = −0.885 + 0.922·log(body mass [kg]), (r² = 0.77, F = 26.8, P < 0.001, n = 10). The Arabian oryx had the lowest mass-specific water-influx rate (31.5 ml kg^−0.922 day⁻¹), only 32% that of the camel (99.3 ml kg^−0.922 day⁻¹), emphasizing the degree of evolutionary specialization in oryx. Between June and September, oryxes grazed primarily on 3 grasses, Panicum turgidum, Lasiurus scindicus, and Stipagrostis. P. turgidum, taken in largest quantity, had the highest moisture content, 35–45% per g of wet matter. Dry matter intake averaged about 3.1 kg during the summer months; plant intake varied inversely with moisture content.

In 1990 the population of the red-necked ostrich Struthio camelus camelus in the Aïr and Ténéré National Nature Reserve, Niger, was estimated at c. 1600 individuals. During a 14-day survey carried out in the protected area in October and November 2000 no evidence of recent occurrence of ostriches was found, and it appears that the population size has dramatically declined in its favoured habitat. The species seems to have been severely persecuted during the civil war of 1991–1997. Although a small population had remained in the protected area after the conflict, the occurrence of further poaching suggests that remaining individuals are threatened with extirpation.