Depending on whom you talk to it's either the second largest canyon in Africa, after the Blue Nile Gorge of Ethiopia, or the second largest in the world after Arizona's Grand Canyon. But regardless of where it ranks in the geographic hierarchy, the Fish River Canyon in southern Namibia is one whopping big hole. More than 160km long, 25km wide, and half a kilometre deep it slices through layers of sedimentary rock that span at least 1,000 million years of geological time. Rocks now exposed in the base of the canyon were deposited during the Proterozoic Era when the first simple forms of life, little more than clumps of organic molecules, were learning how to procreate in the earth's primordial oceans. Higher in the canyon's walls layer after layer of younger rocks shales, sandstones, conglomerates contain a fossil record of the creatures, now long extinct, that inhabited the shallow sea that once covered this part of the globe.
Despite its size the Fish River Canyon sneaks up on you without warning. After driving for hours across the monotonously flat semi-arid upland of central Namibia we arrived at a viewpoint on the canyon rim and suddenly there it was a sweeping vista across the winding inner canyon to the distant rim of the outer canyon. This spectacular gash in the earth is actually a canyon within a canyon. The comparatively straight outer canyon was formed by faulting when the region was uplifted by tectonic forces and the accumulated pile of marine sediments was raised high above sea level. The ancestral Fish River set a shallow meandering course across the flat bottom of this fault-bounded rift valley and as uplift continued the river compensated by eroding deeper into its bed. And over the next 50 million years or so it carved out the winding inner canyon which amplifies but faithfully preserves the twists and turns of the river's original course.
It was late afternoon when Betty, Odie and I arrived at Hikers Viewpoint. With only three of us we had the flexibility to set our own agenda and the luxury of being totally self contained. Odie, our hard-working South African guide, agreed to drive the landcruiser south to the next viewpoint and start dinner there while Betty and I hiked back along the canyon rim. A sign beside a trail leading into the canyon warns hikers not to go down.
Although we hiked only about five kilometers along the rim of the outer canyon the tightly meandering inner canyon offered an ever-changing kaleidoscope of switchbacks, cliffs, and narrow-crested ridges. Except for sparse euphorbia bushes and a few quivertrees there is no vegetation on either the plateau surface or the canyon walls. A lone dassie, basking on a sunny ledge, was the only other living thing we saw on our short hike. These strange little animals, the worlds smallest hoofed mammal, look more like Whistler marmots than elephants. Yet biologists, in their scientific wisdom, claim that dassies, or rock hyrax, are the African tuskers closest living relative.