Page 9 - American Jaguar; Big Cats, Biogeography, and Human Borders

CHAPTER 1
RULER OF

THE SKY

ISLANDS

he Sierra Madre Occidental, or “mother
Tmountains to the west,” is an immense
mountain range that forms the backbone of
western Mexico. This towering range starts in
the tropical lands of southern Mexico and runs
about 780 miles (1,250 km) north to the arid, dry
deserts in the state of Sonora, which borders the
United States. Here, the mountain range begins to
split apart into isolated peaks separated by rolling
grasslands and desert. These are the Sky Islands,
a loose network of about sixty small mountain
ranges. The Sky Islands sprawl northward into the
United States in southeastern Arizona.
The Sky Islands provide high-altitude habitats
for animals to escape the suffocating heat on the
desert floor, where summer temperatures can
easily exceed 115 F (46 C). Some of these Sky
Island peaks reach almost 12,000 feet (3,657 m)
above sea level. At this altitude, the mountains
are covered in lush forests of oak and pine and are
often snowcapped in the winter months.

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