Noted ornithologist George Miksch Sutton began fieldwork in Mexico in the late 1930s,[3] and by 1941 Sutton and Olin Sewall Pettingill Jr. embarked on a series of extended stays in the Gómez Farias region and found their way to Harrison's small ranch followed by a succession of ornithological publications.

In 1965, to protect the ecosystem, Harrison transferred his land to a non-profit corporation in cooperation with Texas Southmost College and the Gorgas Science Foundation.

In 1983, the Gorgas Science Foundation established Rancho El Cielito by purchasing land along the Sabinas River, just outside the reserve, to preserve part of a riparian ecosystem.

[13] An ecological interpretive center is reached by paved road a few miles west of the town of Gómez Farías.

The interpretive center, located at an elevation of 360 metres (1,180 ft) offers good views of the tropical forest and facilities for visitors.

[14] The reserve occupies portions of four Mexican municipalities in the state of Tamaulipas: Jaumave, Llera de Canales, Gómez Farías, and Ocampo.

[1] The principal access is a road, initially paved, from the town of Gomez Farias into the interior and higher elevations.

The reserve is characterized by steep, north-south trending mountain ranges, eastern extensions of the Sierra Madre Oriental, made up of limestone.

Included are species associated with the temperate climate of the eastern United States such as maple (Acer skutchii), hickory (Carya ovata), hornbeam (Carpinus tropicalis), and redbud (Cercis canadensis).

[18] Mammals: Six species of cats, none abundant, are found in the reserve: jaguar, mountain lion, ocelot, margay, jaguarundi, and bobcat.

[1] The large cats, jaguars and mountain lions, are generally regarded favorably by the people living in the reserve.

[19] Camera traps set out in tropical forests photographed eight male, female, and juvenile jaguars in a survey area of 135 square kilometres (52 sq mi).

[1] The area is very rich in bird diversity, just a few of the tropical species occurring in the area include the bare-throated tiger-heron (Tigrisoma mexicanum), boat-billed heron (Cochlearius cochlearius), plumbeous kite (Ictinia plumbea), ornate hawk-eagle (Spizaetus ornatus), bat falcon (Falco rufigularis), great curassow (Crax rubra), yellow-headed parrot (Amazona oratrix), military macaw (Ara militaris), squirrel cuckoo (Piaya cayana), northern potoo (Nyctibius jamaicensis), green-breasted mango (Anthracothorax prevostii), mountain trogon (Trogon mexicanus), blue-crowned motmot (Momotus momota), pale-billed woodpecker (Campephilus guatemalensis), ivory-billed woodcreeper (Xiphorhynchus flavigaster), barred antshrike (Thamnophilus doliatus), yellow-throated euphonia (Euphonia hirundinacea).

The town of Jaumave, Tamaulipas at the northwestern entrance to the reserve receives only 17.9 inches (450 mm) of precipitation annually and has a semi-arid, near-desert climate.