Put down the Morton's salt! Researchers think they've figured out where bonobos are getting their iodine from, and it might help us understand how we evolved our big brains.

Bonobos (sometimes called pygmy chimpanzees) are some of our closest living relatives. They're the taxonomic sister-group to chimps and are famous for their "make love, not war" lifestyle. They're also endemic to the central Congo Basin, a region the WHO classifies as having few natural sources of iodine.

Iodine is really important for thyroid function in adults and for fetal and infant brain development. And while we don't know what bonobos' iodine requirements are, we know that humans are very sensitive to iodine deficiency - so our closest living relatives and our ancestors might also have been.

But the bonobos in the LuiKotale forest in Salonga National Park, DRC, don't seem affected by iodine deficiency in the way that some of the people in the area were (prior to iodine supplementation). And it might be because they eat aquatic herbs that are rich in iodine about once every two weeks.

So what does that mean for the evolution of our big brains? The researchers who observed this behavior suggest that adequate iodine consumption was a prerequisite for human cognitive development and that iodine sources were likely to have been plentiful in the coastal areas and wetlands these hominins frequented. Finding these iodine sources further inland, in the Congo Basin, means that hominins weren't necessarily restricted to coastal environments, and that aquatic herbs (along with animal protein) might've been really important in the evolution of our brains.

(Ed: Yes, those are chimps in the picture, not bonobos. There aren't many free stock images of bonobos that weren't taken in zoos available. If you'd like to email us to talk about it, hello@massivesci.com, thanks.)