Colour:
The Arabian oryx is a uniform white, while the flank stripe is absent or only an indistinct smudge. The lower limbs are a chocolate brown to black with the exception of pure white patterns. The face and nose have dark patches and there is often a dark stripe that runs under the neck to the forelegs. In summer dark patches are lighter and often absent altogether. Calves are a uniform brown colour.
Weight:
Female oryx weigh about 80 kg and males about 90 kg. Occasionally males may reach 100 kg.
Age at maturity:
Female oryx may conceive at just over 12 months old. Male oryx may be mature by two years but in the face of competition from other males are unlikely to start breeding until at least three years.
Birth Season:
Oryx may calve in any month of the year but there is a general pattern of births in the winter period December to April. This is thought to be largely the consequence of winter rains influencing conception.
Birth rate:
Most female will calve annually, provided adequate food resources are present. After 18 months of drought females are less likely to conceive and may be unable to suckle their calves. Births are usually single with only one case of twins since the reintroduction began in 1982.
Sex Ratio:
Birth sex ratio is usually 50:50 (male: female) and in the wild under normal conditions the sex ratio of the population is 50:50.
Gestation Period:
Usually about 8.5 months.
Life expectancy:
In good grazing conditions oryx may live to 20 years. In drought life expectancy is greatly reduced.
Causes of death:
During drought oryx die from malnutrition and dehydration. Other causes of death have been fighting wounds (amongst males), snakebite, drowning following floods and disease. Male aggression and predation have caused the death of a small number of calves.
الثلاثاء 29 أبريل 2008 - 22:37
