Walking dead. (Photo in Zambia: Patrick Bentley/www.patrickbentley.com, by permission)

The lion, long regarded as the king of wild African landscapes, is now rapidly vanishing from much of the continent.

Where perhaps 200,000 of them roamed across Africa in the mid-twentieth century—and an estimated 500,000 in pre-colonial times—only about 20,000 now remain.

Half of those are likely to disappear over the next two decades, according to a report out today in the Proceedings of the National Academy of Sciences (PNAS).

They are being crowded out by habitat loss, depletion of their prey base by bushmeat hunters, and retaliatory or preemptive killings to protect livestock and people—all symptoms of a sub-Saharan human population on track to grow to four billion people by the end of the century.

Poorly regulated sport hunting also contributes to the problem, according to the report.

Weirdly, this catastrophic decline of one of the most celebrated species on…