The thorny dragon (Moloch horridus) is an Australian reptile found primarily in the arid and semi-arid scrublands and sand plains of central and western Australia. It is instantly recognizable by the dense covering of cone-shaped spines that armor its entire body. This lizard has evolved highly specific traits to survive its harsh environment, including a false head on its neck designed to confuse predators. These remarkable adaptations influence nearly every aspect of its existence, particularly its unique method of obtaining sustenance.
A Diet Exclusively of Ants
The dietary habits of the thorny dragon are highly specialized, defined by the practice of myrmecophagy, or ant-eating. They are obligate specialists, meaning their entire nutritional intake is derived almost exclusively from consuming ants. This singular focus reflects their adaptation to the nutrient-poor, water-scarce desert ecosystems they inhabit.
Thorny dragons show a strong preference for slow-moving, black ants belonging to genera such as Iridomyrmex, commonly known as meat ants, or various harvester ants. These specific prey choices are high in fat and protein, providing the necessary energy for the lizard’s relatively sedentary lifestyle. The thorny dragon will rarely consume any other type of insect, plant matter, or small vertebrate.
To meet their daily energy demands, these lizards must consume ants in staggering volumes. A single thorny dragon can consume between 600 and 3,000 ants in a single feeding session, often lasting several hours. Over the course of a day, a typical adult may ingest many thousands of individual ants, demonstrating the efficiency of its consumption process. This high-volume diet necessitates a specific hunting strategy to maximize intake.
Specialized Feeding Behavior
The method the thorny dragon employs to capture its prey is a direct adaptation to its high-volume diet requirement. The lizard does not actively hunt; instead, it utilizes an ambush strategy, positioning itself directly adjacent to an established ant trail. Once settled, the dragon remains motionless, allowing the continuous flow of workers to pass within easy reach.
The structure of the thorny dragon’s mouth and tongue is perfectly suited for this repetitive task. It possesses a short, non-protrusible tongue that is covered in a sticky, adhesive secretion. When ants pass by, the lizard executes rapid, repeated flicks, lapping up the insects quickly. This sticky-tongue action allows for the ingestion of dozens of ants within seconds, optimizing the rate of consumption.
The lizard’s slow, deliberate movements during feeding are designed to avoid disturbing the ant trail, ensuring a steady, uninterrupted supply of food. The process often involves short, quick bursts of eating, followed by brief pauses before resuming the lapping motion. This stationary feeding technique minimizes energy expenditure, which is an advantage in the resource-limited desert environment.
Unique Water Collection Method
Survival in the arid Australian environment requires a unique mechanism for hydration. The thorny dragon has evolved a remarkable passive water collection system utilizing its highly textured skin and scale arrangement. This system is a sophisticated biological solution for maximizing water intake in an ecosystem where standing water is a rarity.
The skin is covered in microscopic channels and grooves that radiate outward from the body’s midline, running between the scales. These channels function through capillary action, a physical phenomenon where liquid flows in narrow spaces without the assistance of external forces.
When the lizard stands on damp sand, or during early morning dew or light rainfall, moisture is immediately drawn into these grooves. The water then travels upward and across the body’s surface, pulled by capillary forces toward the lizard’s mouth. The dragon simply needs to depress its head slightly to allow the accumulated water to pool at the corners of its mouth, where it can then be swallowed. This system allows the reptile to efficiently harvest available moisture from its surroundings, making external water sources unnecessary for survival.