Author: Mike Cadman
Everyone recognizes giraffes. They are plentiful in many southern African protected areas and impossible to misidentify and, as a result, many people treat them with a casual familiarity.
“Oh, a giraffe” is a common response when they are spotted on a game drive. “Lovely eyelashes.” And there the conversation often ends.
But what is not so well known is that that world’s tallest land mammal, and the heaviest ruminant with large males weighing as much as 1200 kg, also plays a role in the pollination of the flowers of the knobthorn tree Senegalia nigrescens. The flowers are also pollinated by insects and birds and although widely acknowledged the full extent of the giraffes pollination efforts are not fully understood.
“Although flower consumption represents a cost to knobthorn plants giraffes consume only fraction of available flowers and they collect visible amounts of pollen on their heads and necks when feeding,” the authors note in The Kruger Experience: Ecology and Management of Savanna Hetrogeneity by Harry Biggs, Johan du Toit and Kevin Rogers. (2003). “In this way pollen is distributed to other flowering knobthorns throughout the giraffes home range”.
This phenomenon is sometimes mentioned in tree identification guide books and articles about giraffes but is often overlooked.
Knobthorns are widely distributed and are very common around the Rhino Post Safari lodge and Plains Camp in the Kruger National Park and occur along the Zambezi River near Chundu Isalnd. Giraffes, elephants, kudu and impala eat the leaves of knobthorns. In the Kruger National Park some knobthorns are pushed over by elephants and others are damaged by the animals feeding on their bark, resulting in the trees being ring-barked and dying.
Some scientists also question the extent to which giraffes pollinate the flowers. They argue that the giraffes eat so many flowers that they are more destructive than helpful and that insects and birds play a more valuable role.
“Finally, giraffes were plainly highly destructive and detrimental to the trees’ overall fecundity during the season we examined,” the authors of the scientific paper ‘Are giraffes pollinators or flower predators of Acacia nigrescens in Kruger National Park, South Africa?’ (Patricia Fleming, Sally Hofmeyer, Sue Nicolson and Johan du Toit ) note. “If they have a role as pollinators of A. nigrescens then it would appear to be confined to years of superabundant, highly synchronized flowering or it could be in terms of greater quality of pollination service, which may be revealed by genetic analysis of seed.” (Note: the scientific name of the knobthorn has changed since this paper was published in 2006).
So the next time you see a giraffe feeding on the flowers of a knobthorn it’s worth remembering that it is not “just a giraffe” with pretty eyelashes, eyelashes which depending on your sense of aesthetics may be made prettier with a dusting of pollen, it is also fulfilling a role in the complex matrix of biodiversity, as are the tiny insects and small birds visiting the same tree.