Heterotroph is a term used by biologists to describe organisms that must consume other living beings to gain energy, whether plant or animal. All animals are considered heterotrophs, as opposed to plants, which are classified as autotrophs, meaning they derive sustenance from solar energy. Desert ecosystems are home to a wide variety of animal life that expresses the full range of heterotrophic diets.
Mountain lions (Puma concolor) are solitary, adaptable carnivores commonly found in desert regions throughout the southwestern United States. Despite being the second-largest cat in the Americas, mountain lions are rather small, averaging 115 lbs. and measuring less than 3 feet in height at the shoulder. They have a plain, tawny coat with black trim around the eyes, backs of the ears and the tip of the tail. Mountain lions, or cougars, are carnivorous heterotrophs and feed on a wide range of prey, such as insects, small mammals, reptiles and birds, but their most common prey is deer.
Often confused with swine, javelinas (Tayassu tajacu) are heavy mammals found in desert areas throughout the southwestern United States and Central America. They can grow to be 4 feet in length and weigh more than 80 lbs., but despite their small size they are quite strong and aggressive. Javelinas, or peccaries, are omnivorous heterotrophs, feeding on roots, nuts and vegetation as well as small animals. Because of their natural aggression, javelinas cannot be domesticated and have been known to attack humans who encroach on their territory.
Black-tailed jackrabbits (Lepus californicus) are a species of hare common throughout the western United States, especially in desert regions. They are known for their exceptionally long ears and powerful hind legs, which are common in all species of hare but especially pronounced in this species. They displays unusual black and tan, peppered colorations with pale undersides and dark ears. Typically crepuscular in habit, black-tailed jackrabbits are herbivorous heterotrophs that feed on cacti, grasses, mesquite shoots and other vegetation. They are common prey for mountain lions, bobcats and raptors.
King snakes (Lampropeltis getula) are known for their showy striped markings and ability to withstand the venom of rattlesnakes, which are their frequent prey. Depending on their subspecies and locale, king snakes express different color variations, including black, white, red, yellow and tan stripes. They are constriction killers, suffocating prey with their long, muscular bodies. King snakes are not venomous or especially swift, so they rely on a system of bluffs and defensive postures to ward off predation, such as hissing, playing dead, exuding a foul smelling substance and even mimicking rattlesnakes by vibrating their tail in dry leaves.