Travel Reference
In-Depth Information
When you fl oat down the Bensbach River in southern New Guinea, you
might think that you are in Australia. But in fact the tree- and grass-covered
plain nurtured by the Bensbach resembles the Australia of some wetter past,
not the rust-red and often forbidding Australia of the present.
The fl at coastal plain of southern New Guinea is watered by the fl ow
of year-round rivers such as the Fly and the Bensbach that originate in the
island's mighty Central Range. These rivers nourish a countryside far lusher
than the fl at Australian plains across the Torres Strait to the south. The coastal
plains of Australia, equally pancake-fl at, have no mountains nearby to feed
their more seasonal rivers. When sea levels rose after the last Ice Age, they
cut northern Australia of from the rivers of New Guinea's central massif.
The Bensbach winds through green beds of reeds, where Australian
pelicans swim like graceful swans in an English park. Spangled kookabur-
ras laugh from the trees, and clusters of brown night herons watch for fi sh
from the upper branches. Collared kingfi shers fl it along the river's banks. A
fi sh eagle scoops a huge fi sh from the river and fl ies away. And, to complete
the picture, mobs of wallabies hop into the lush undergrowth after drinking
from the river.
The scenery along the river must have been very like the scenes that
greeted the fi rst human migrants between New Guinea and Australia—with
one notable exception. Then it was possible for people migrating south to fol-
low the rivers all the way to Australia. Now the Bensbach fl ows into a wind-
swept estuary and disappears into the waters of the shallow Torres Strait.
This strait, 180 kilometers wide, would seem to be a formidable obstacle
to human migrations. But in those distant days it did not exist. The rivers of
New Guinea watered a land bridge 1,000 kilometers wide that joined New
Guinea to the Australian mainland.
The bridge has been present intermittently during the past 2,500,000
years, whenever ice ages caused sea levels to drop. It was especially wide
and substantial during much of the past 100,000 years, as the world went
through an unusually severe ice age. Then, during the most recent 10,000
years, the world warmed. Ocean levels rose an astonishing 200 meters, sepa-
rating Australia from New Guinea.
