The Arabian oryx (Oryx leucoryx) is a large, white antelope native to the deserts and steppes of the Arabian Peninsula. Its survival in arid environments is directly linked to highly specific feeding and hydration strategies. The oryx’s diet is a testament to its adaptation, allowing it to thrive where water and vegetation are scarce. Its lifestyle revolves around locating and consuming specific plant matter for both energy and moisture.
Primary Diet Composition
The diet of the Arabian oryx consists primarily of grasses and herbage, making it a grazing animal, but it is highly opportunistic and varied. The specific plants consumed depend heavily on the irregular and unpredictable rainfall patterns across the desert habitat. Following a rain event, the oryx will seek out new plant growth, which provides a temporary source of high-protein vegetation.
The grasses of the genus Stipagrostis are an important food source in areas like Oman. During certain seasons, the flowers of Stipagrostis plants offer the highest concentration of crude protein and water. In the hot summer months, oryx herds primarily graze on three specific grasses: Panicum turgidum, Lasiurus scindicus, and Stipagrostis. The largest quantity consumed is often Panicum turgidum, which is preferred for its high moisture content, even when mature.
Specialized Feeding Behavior
The oryx demonstrates selective feeding behavior, moving slowly across the landscape to conserve energy while choosing the most nutritious and water-rich plant parts. This mobility is guided by an ability to detect distant rainfall, prompting the herd to travel vast distances toward areas with sprouting vegetation. Their foraging activity is also timed to avoid the most intense heat of the day.
The animals are most active during the cooler hours of the early morning and late evening, a pattern known as crepuscular feeding. During the peak heat of midday, they rest in shallow depressions dug in the sand under shrubs to stay cool, limiting energy expenditure. In dry periods, when surface vegetation is severely depleted, the oryx will use its hooves to dig up bulbs, tubers, and roots. This behavior grants access to underground plant storage organs containing moisture and stored carbohydrates.
Water Acquisition and Moisture Intake
The Arabian oryx has developed strategies to survive long periods without access to standing water, sometimes for several weeks. They rely heavily on the moisture content within their food, selecting succulent plants and melons to meet their hydration needs. For example, the preferred summer grass, Panicum turgidum, is consumed in large quantities because it contains between 35% and 45% moisture per gram of wet matter.
This dietary strategy allows the oryx to maintain an exceptionally low mass-specific water-influx rate, estimated to be only 32% that of the camel. A small but consistent amount of their total daily water intake, approximately 14.2%, is generated internally through the metabolic breakdown of food, known as oxidative water. They also consume condensation, or dew, that collects on rocks and vegetation during the early morning hours after heavy fog.