The saguaro cactus, Carnegiea gigantea, stands as an emblem of the Sonoran Desert. Growing over 40 feet tall, these majestic cacti can live for up to 200 years. They provide sustenance and shelter for numerous species, supporting a wide array of desert life from insects to mammals and birds.
Mammals That Feast on Saguaro
Various mammals in the Sonoran Desert consume parts of the saguaro cactus, primarily for its nutritional value and moisture, especially during dry periods. Javelina, also known as collared peccaries, eat fallen saguaro fruit and occasionally gnaw on the lower stem. Packrats use the saguaro for food and shelter. They construct nests from cactus ribs and pads and consume the fruit, flesh, and seeds when other food is limited.
Jackrabbits, mule deer, and bighorn sheep may consume the saguaro’s flesh for moisture when other water sources are unavailable. Desert rodents, such as mice and rabbits, also eat the seeds and fallen fruit.
Birds Drawn to Saguaro’s Bounty
Birds rely on saguaro flowers for nectar and pollen, and its fruit for sustenance. Gila woodpeckers and gilded flickers excavate cavities in the saguaro’s flesh for nesting; these “saguaro boots” are later used by other birds like elf owls. Woodpeckers also consume insects and saguaro fruit. Gilded flickers primarily eat insects but also feed on saguaro pollen and fruit.
White-winged doves frequent saguaro flowers for nectar and pollen, making them important pollinators. They also consume the saguaro’s sweet red fruit, which is rich in seeds. Though their digestion can be harsh on seeds, some pass through unharmed, aiding dispersal. Mourning doves, various thrashers, and hummingbirds also feed on fruit, seeds, or nectar.
Tiny Eaters: Insects and Invertebrates
Insects and invertebrates interact with the saguaro, from pollination to decomposition. Honey bees are significant pollinators of saguaro flowers, collecting nectar and pollen. Some insect larvae bore into the saguaro’s flesh. For example, the cactus longhorn beetle (Moneilema gigas) larvae tunnel through the stems and roots of saguaro seedlings, sometimes causing damage. Adults of this beetle also feed on the cactus surface.
While many insects do little harm, some, like cutworms (moth larvae), can consume young saguaros. Termites, such as the desert-encrusting termites (Gnathamitermes perplexus), recycle dead plant material by consuming the outer layers of the saguaro’s base and building mud tubes, but they do not typically harm living cacti. Ants also collect nectar from flowers or seeds, and various beetles and flies are part of the ecosystem within a rotting saguaro.