Page 10 - American Jaguar; Big Cats, Biogeography, and Human Borders

During the first few million years of Pseudaelurus’s reign, sea
levels fell considerably, exposing land between the continents of Asia
and Africa and between Asia and North America. Early humans and
other animals moved across the exposed lands, known as land bridges,
to settle in other regions. In North America, early felids crossed the
Bering Land Bridge, which connected what is now eastern Russia to
Alaska. As the first descendants of Pseudaelurus adapted to their new
homes, they developed new and different traits for survival. Eventually,
different species of cats evolved as the environment changed. One of

THE BIG CATS

Scientists view all species of the genus Panthera as the big cats.
In the twenty-first century, the jaguar is the only member of this
genus in the Americas. Panthera also includes the large cats
of Africa—lions and leopards—as well as the tigers of Asia.
Panthera is the oldest of cat lineages, or descendants. It first
appeared in the fossil record about 10.8 million years ago.
Besides being really big, all big cats can roar. All mammals,
including cats, have a larynx, an organ in the neck that helps
produce sound. (In humans, we call it a voice box.) The larynx
is made up of many muscles, ligaments, and small bones. One
important bone that allows the larynx to make sounds is the
hyoid bone.
All members of Panthera have a hyoid bone that is not
entirely ossified, or hardened. The hyoid bone in a big cat is
a series of small bones that are connected with ligaments and
other tissues. This allows the hyoid bone to be very flexible.
When air is forced over the hyoid, the bone reverberates to
make a deep, thunderous vocalization, or a roar.
Scientists view all other species of cats as small cats. These
include ocelots, bobcats, lynxes, and domestic cats. Even the

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