Gentle giraffes threatened with 'silent extinction' In Kenya, as across Africa, populations of the world's tallest mammals are quietly, yet sharply, in decline. Giraffe numbers across the continent fell 40 percent between 1985 and 2015, to just under 100,000 animals, according to the best figures available to the International Union for Conservation of Nature (IUCN). But unlike the clarion calls sounded over the catastrophic collapse of elephant, lion and rhino populations, less attention was paid to the giraffe's private crisis.