Scientists have for the first time observed wild bonobos (Pan paniscus), a hominoid species endemic to the central Congo basin, searching for and eating aquatic plants rich in iodine, a mineral nutrient which is critical for normal growth, development and functioning of both brain and body.
An adult female bonobo retrieving water lillies (Nymphea lotus) from a back water. Image credit: Zana Clay, LuiKotale Bonobo Project.
“Our results have implications for our understanding of the immigration of prehistoric human populations into the Congo basin,” said Dr. Gottfried Hohmann, a researcher at the Max Planck Institute for Evolutionary Anthropology.
“Bonobos as a species can be expected to have similar iodine requirements to humans, so our study offers — for the first time — a possible answer on how pre-industrial human migrants may have survived in the Congo basin without artificial supplementation of iodine.”
Dr. Hohmann’s team observed two habituated communities of wild bonobos in the LuiKotale forest at the western border of Salonga National Park, Democratic Republic of the Congo.
The behavioral observations were combined with data on the iodine content of plants eaten by bonobos.
The researchers found that the aquatic herbs consumed by bonobos are a surprisingly rich natural source of iodine in the Congo basin, a region that was previously thought to be scarce in iodine sources.
Bonobos in LuiKotale Forest, Salonga National Park, Democratic Republic of Congo, consuming iodine-containing aquatic plants. Image credit: Cédric Girard-Buttoz, LuiKotale Bonobo Project.
“Evolutionary scenarios suggest that major developments of human evolution are associated with living in coastal areas, which offer a diet that triggered brain development in hominins,” Dr. Hohmann said.
“Our results suggest that consumption of aquatic herbs from swamps in forest habitat could have contributed to satisfying the iodine requirements of hominin populations used to diets prevalent in coastal environments.”
“The study potentially answers the question of how apes obtain iodine from natural food sources, when many populations inhabit areas considered to be iodine deficient. Other apes such as chimpanzees and gorillas have also been observed eating aquatic herbs, which suggests that they could be obtaining essential iodine from these sources.”
The findings appear in the journal BMC Zoology.
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Gottfried Hohmann et al. 2019. Fishing for iodine: what aquatic foraging by bonobos tells us about human evolution. BMC Zoology 4 (5); doi: 10.1186/s40850-019-0043-z
