Mexican biosphere reserves are areas of huge biological diversity; regions where the species are endemic and uninfluenced by humans in a threatened habitat. The Pinacate reserve holds over 500 plant species, over 50 mammal species, over 40 reptile species, and over 200 bird species.

Edge of lava flow near Mt. Tecolote

As grand and elusive as the name "Sierra Del Pinacate" sounds, its namesake is a simple insect—the Pinacate beetle. This name is derived from the Aztec name for this beetle, "Pinacatl." Its primary defense against predators is its ability to emit intensely awful scents. It also survives well when it gets cold. Its black coloring enables it to absorb heat while repelling harmful rays.

Only a few predators can overcome its defenses. Black widows entangle them in their webs and wait for them to exhaust their spray before feasting. Some desert mice have learned to stuff the beetle's abdomen in sand and eat them from the head down.

Perhaps the most symbolic creature of Pinacate is the Sonoran Pronghorn Antelope. A subspecies of North America's Pronghorn Antelope, many scientists believe only a handful exist—as few as 200 by some counts. The pronghorn antelope has no relation to the African antelope, and is actually the sole remaining species of an ancient family. The Sonoran pronghorn's coloring is tones of beige, brown, and black. It has a rather small head and unusually large eyes. Its horns are often mistaken for antlers.

Pinacate is home to many other unique mammals: big horn sheep, javelinas, coatimundi, kangaroo rats, and the long-nosed bat are a few. The birdlife of Pinacate is very active. During the hotter months of April to September, they are visible almost only at night, when they use the cover and cool of night to search for food.

Pinacate is a favorite place for herpetologists, who come here to study a wide variety of lizards, snakes, and toads. Many reptile varieties have developed darker skin than nearby cousins of the same species, a prime example of natural selection.

One of the most common lizard species in Pinacate is the southern desert horned lizard. Able to blend in with the dark ash, this lizard thrives by eating ants, other insects, and occasionally plants. The reserve is also host to the endangered desert tortoise, the burrowing tree frog, Gila monsters, and the desert iguana.

Plant species abound. As in most North American deserts, there is plenty of creosote, ocotillo, mesquite, and a variety of cholla cacti. The famous saguaro cactus is often considered the icon of the Sonoran desert. In Pinacate, it shares its grandeur with two similar columnar species: the organ pipe and the senita.