Cacti are resilient plants of arid regions, effectively storing water and serving as a crucial resource in water-scarce ecosystems. They provide sustenance and hydration, forming a central part of the desert food web for numerous inhabitants.
Mammals That Consume Cacti
Several mammals in desert environments have adapted to include cacti in their diets. Javelinas, or collared peccaries, frequently consume prickly pear cacti, including roots, fruit, stems, and pads. These pig-like mammals use strong teeth and hardened palates to process spiny material, often uprooting entire plants. Their tough skin and coarse snout hair protect them while feeding.
Desert packrats, also called woodrats, carefully consume cacti, targeting the fleshy interior while avoiding spiny sections. These rodents use powerful jaws and molars to chew through the tough flesh. Other rodents like ground squirrels, kangaroo rats, and prairie dogs also eat cactus pads, stems, fruits, and seeds, often focusing on the base or younger pads where spines are less dense. Jackrabbits similarly feed on cacti, especially juicy parts near the base with fewer spines.
Bighorn sheep, seeking moisture, break open barrel cacti with their powerful horns to access the soft inner flesh. Camels, known for thriving in deserts, consume tough, thorny vegetation, including cacti. Their thick, leathery lips and a mouth lined with cone-shaped papillae allow them to handle prickly plants, guiding spines safely down their throats.
Reptiles and Insects That Feed on Cacti
Reptiles also rely on cacti as a food source. The desert tortoise incorporates cacti into its diet, favoring prickly pear pads and fruits, particularly spineless varieties, using its tough, hardened beak to grind them down. Chuckwallas, primarily herbivores, feed on cactus fruit, flowers, and buds, using a side-to-side head shaking motion to tear off leaves and blossoms.
Numerous insect species also feed on cacti, sometimes with specific life stages adapted to different parts. The cactus longhorn beetle, for instance, has larvae that bore into cactus roots and stems. Adult beetles feed on chollas, prickly pears, and young saguaros, often nibbling on spineless areas. The cactus bug uses piercing-sucking mouthparts to extract sap from cactus pads, fruits, and flowers, leaving characteristic light spots. Cochineal insects are small, soft-bodied creatures that suck sap from nopal cacti, appearing as tiny white clusters on the pads.
Overcoming Cactus Defenses
Animals consuming cacti have developed various strategies to overcome the plants’ natural defenses, such as sharp spines and chemical compounds like oxalic acid. Behaviorally, many animals carefully manipulate the cactus. Iguanas, for example, use their claws to remove larger spines before eating pads and fruit. Camels employ a rotational chewing motion that helps align cactus spines vertically, reducing injury as the plant moves down the throat.
Physiological adaptations also neutralize cactus toxins. Javelinas possess a kidney modification enabling them to excrete oxalic acid, a compound found in many cacti that can be toxic in high concentrations. Desert packrats have specialized gut bacteria that break down both cellulose and oxalic acid in cactus flesh. Camels feature a multi-chambered stomach with bacteria that digest cellulose, allowing them to process fibrous parts of cacti.
Physical adaptations further protect these animals. Camels have thick, flexible, leathery lips and a hardened palate to minimize pain from spines. Javelinas are protected by their tough snouts and coarse body hair when uprooting spiny plants. Desert tortoises, with robust beaks, handle the abrasive texture of cactus pads. The cactus longhorn beetle’s exoskeleton provides a physical shield against spines, enabling it to move and feed on the plant’s surface.