the malinke word for the djembefola hats is "Naado." not sure on the spelling but the pronunciation should be "Nah doh" with the emphasis on the first syllable. the word translates to "look here."
traditionally back in the day, the caps were made out of leather from either a cow or horse with the tuft of hair being from the nape of a horse. the horse hair symbolizes strength and power. my teacher said that djembefolas would keep gri gri on the inside of the caps usually sewn in to help protect the djembefola and their drum from bad spirits and bad energy. sometimes you'll see mirrors sewn into the sides of the caps. this is also a form of gri gri in that all negative energy reflects back to the person giving it. he said there's probably only a handful of djembefolas in the village that still keep the gri gri in their Naado.
nowadays, they are a part of the costumes for ballets and percussion groups all over the world.