The Thorny Devil, scientifically known as Moloch horridus, is a small reptile inhabiting the arid scrublands and sandy deserts of central and Western Australia. Its body is covered in large, conical spines and camouflage coloration, which help it blend into the harsh, dry environment. This lizard’s appearance is an adaptation to protect it from predators, but its survival in the desert is equally dependent on a set of highly specific feeding habits. The Thorny Devil has developed unique behavioral and anatomical traits that allow it to exploit a single, abundant food source in an ecosystem where sustenance is otherwise scarce.
The Highly Specialized Ant Diet
The diet of the Thorny Devil consists almost exclusively of ants, a feeding strategy known as obligate myrmecophagy. It focuses primarily on small, black ant species, most often those belonging to the genus Iridomyrmex. It may also consume ants like Crematogaster when they are available on vegetation, but the Iridomyrmex species found on terrestrial trails form the bulk of its meals. This extreme specialization is a necessity in its habitat, reducing competition from other insectivorous reptiles that pursue a more varied diet.
Consuming ants presents a nutritional challenge because each individual ant provides only a small amount of energy. Ants are low in calories but are a concentrated source of protein and certain nutrients. To meet its daily energy requirements, the Thorny Devil must consume a massive volume of these small insects. Its metabolism is specifically adapted to efficiently process this high-volume, low-energy food source, sustaining the lizard’s slow, deliberate lifestyle.
Locating and Tracking Prey
The Thorny Devil’s method of finding food is a slow, strategic process. It locates its food source by searching for established ant trails, which are long, organized lines of ants moving between their nest and a food source. The lizard uses a combination of visual cues and chemical signals to detect these insect highways on the desert floor. Once a trail is found, the Thorny Devil moves slowly or positions itself strategically near or directly over the path of the marching insects.
The most active foraging often takes place during the cooler parts of the day, specifically the morning and late afternoon, when the ants are most active outside their nests. The lizard will remain relatively stationary for long periods, allowing the continuous flow of ants to pass directly under its snout. This behavior minimizes the energy expenditure required for hunting, which is a major advantage for an animal living on a low-energy diet in a hot environment.
Consumption and Intake
Once positioned on an ant trail, the Thorny Devil begins the process of consumption. It possesses a short, sticky tongue that can flick out and retrieve individual ants with remarkable speed and precision. The lizard’s small mouth and specialized jaw structure are optimized for this task. It targets smaller ants and avoids larger or strongly defensive species, ensuring a steady, manageable flow of food.
A single feeding session can last for an extended period, allowing the lizard to consume an enormous quantity of prey. Estimates suggest a single Thorny Devil can ingest between 600 and 3,000 ants in one sitting, and potentially 2,000 to 5,000 ants over the course of a day. After consumption, the digestive process is slow due to the tough, chitinous exoskeletons of the ants. The lizard’s digestive tract is adapted to break down this hard material and efficiently extract the nutrients from the sheer volume of ingested insects.