July 4, 2008 -- "Give me your tired, your poor, your huddled masses yearning to breathe free," is the opening stanza of the poem engraved on the Statue of Liberty in New York Harbor. Lady Liberty serves as a historical reminder that America is a nation of immigrants.

While America's immigrant history is well-known, we are also a nation of emigrants -- many of whom left millions of years ago for other parts of the world.

Camels, who now inhabit the Sahara desert, are our fellow Americans, once freely wandering the American plains, long before human arrival. The fossil record, from over 20 million years ago, shows that every camel came exclusively from here.

"The original camel was North American," said Guy Robinson, a professor at Fordham University who studies migration. "And it gave rise to all the camels you find throughout the world."

The North American breed looked similar to today's traditional two-humped camel, but archaeologists think that our camels were taller and possibly did not have humps.

Scientists can show that camels roamed this continent -- from Alaska to Florida -- for 30 million years until they crossed into Asia, roughly 13,000 years ago.

Camels and a variety of other mammals migrated across the Bering land bridge, a temporary bridge of land, roughly 1,000 miles, which connected present-day Alaska to Siberia. From there they migrated down to the Middle East and Asia.

Other camels took a different route, heading south, across the Panama land bridge to Central America. In North America, the ice age, hunters and disease caused the camels that remained to become extinct by the end of the Pleistocene era.

Camels, llamas, horses and zebras descend from American stock, according to Robinson. Interestingly, Western camels more closely resemble llamas in terms of biology than camels today.

To some, camels are seen as solely a tourist attraction, but they have become part of the social fabric in many countries.

While America is better known for giving birth to liberty and the Constitution, Americans can now claim bragging rights to our camel emigrants, roaming the Sahara desert.