Geography Reference
In-Depth Information
Figure 12-1:
The
world at the
height of the last
ice age. The
space between
the bolded lines
depicts what
used to be solid
land.
The land bridges lasted for thousands of years. Formerly ocean bottom, they became grasslands and
woodlands that provided habitat for animals. Most importantly, of course, the land bridges provided
firmament that allowed humans (over many generations) to migrate and occupy lands that had been
unknown or out of reach. For example, people could have walked from present-day France to Ireland
(see Figure 12-1). Similarly, of course, the ancestors of Native Americans migrated over dry land
from Siberia to Alaska. Other connections are also evident on Figure 12-1, though some are contro-
versial. We're not certain, for example, whether the Strait of Gibraltar was ever a land bridge and
opinion varies as to the location of ice age coastlines in the Indonesian and Philippine archipelagos.
Eventually,thelasticeagecametoanend.Climateswarmed,andasglacialicerecededtheirmeltwa-
ters flowed to the oceans, which rose and inundated the land bridges. Thus, continents and land bod-
ies became disconnected — just as they had been before the ice age started. But something significant
had happened between the appearance and disappearance of the land bridges. Humans had migrated
across them, giving rise to native populations that, many generations later, would greet European and
other explorers.
Voyaging afar
Sometimes people were separated from their nearest neighbors by thousands of miles of ocean far
too deep (14,000 feet or so) for any land bridge to explain their arrival. Therefore, ancient voyages
of substantial scale must have occurred. Relatively recent research suggests the requisite navigational
skills were based on knowledge and application of star positions, bird behavior, cloud types, ocean
swells, and wave refraction. For example, when Captain James Cook reached the Hawaiian Islands
in 1778, he found natives of Polynesian ancestry. Thousands of miles of ocean separated these people
from any neighbors, proving that voyages had occurred. Other islands were found to have similar
populations, and not just in the Pacific. Thus, the Merino people of Madagascar, off the southeast
African coast, speak a Polynesian language.
