泛滥之谜 12

The tropical sun burns off the Nile's shallow waters

leaving a shifting mosaic of pools and new grassland.

Now it's time for the Dinka to return.

But others fare less well as the land re-emerges.

This catfish could easily find itself stranded

but it has a curious ability that might just save it.

If it can't swim, it'll crawl.

Specially adapted fins allow the catfish to walk on its elbows.

Like the lungfish, it can also breathe air.

It may have to perform this trick many times

as its habitable world gets smaller by the day.

Meanwhile, the kob are on the move again.

Their world is expanding rapidly.

As the floodwaters recede

a huge green carpet of new grass rolls out before them.

This explains how the Sudd can support such massive herds.