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.
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.
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.
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.
Birth sex ratio is usually 50:50 (male: female) and in the
wild under normal conditions the sex ratio of the population
Usually about 8.5 months.
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.