Some of the Africans carried away to captivity to the West must have been Jews. Check this article. Many rituals of Judaism are found in indigenous African cultures.
JEWISH ROOTS IN SUDAN
By: William Levi Ochan Ajjugo
When most people think of Judaism in black Africa, they think of the so-called Falashas, Bet Israel, Ethiopian Jews who have kept the essentials of biblical Judaism despite being isolated geographically from other Jews for thousands of years.
The Falashas are in fact the tip of the iceberg. Judaism came to Africa long before Islam or even Christianity, itself an early arrival. Hebrews have been in Africa hundreds of years before the exodus from Egypt. So influential was ancient Judaism in northern and eastern Africa that anthropologists have devised a test to tell whether a given tribe or people has Hebraic roots: It does so if males are circumcised at age of 1 or earlier.
I am from South Sudan, the largely Christian, African portion of the Sudan, which has long been dominated by Arab Muslims to the north, in Khartoum. I am from a tribe called the Madi, and while we did not retain Judaism as thoroughly as did the Falashas in neighboring Ethiopia, I am amazed as I look back at how many of our customs seem to have come from the Hebrew Scriptures.
Among Christians and non- Christians like, one G-d was worshipped. As in the Book of Leviticus, blood sacrifices were offered or sins. The worst sins required the sacrifice of a sheep, the ones below these a boat, and the "least" sins a chicken. A hereditary group of elders or priests decided which to sacrifice, and presided over these and other ceremonies.
Dietary laws were practiced; certain animals were "unclean" and could not be eaten. Ceremonial washing of hands was required when leaving home. Certain days of the year were set apart as holy. On such days, all was pledged to the one G-d of the heavens who forgave sins.
The Madi also use a ram's horn ("bilah") to call people together for various purposes. My father, who was an hereditary elder, would often blow the bilah to gather the people together for a ceremony or to discuss a matter of importance.
If a man died, his brother married his widow. This is in Leviticus, and also is imbedded in Madi culture, as is the "kinsman-redeemer" custom found in the Book of Ruth in connection with Boaz's marrying Ruth. In Ruth 4:7, it says that "in earlier times in Israel", the redemption and transfer of property became final when one party took off his sandal and gave it to the other. This is precisely what the Madi did when I was growing up.
In Deuteronomy 15:19, the children of Israel were commanded to set apart for the L-rd all first-born males of their herds and flocks. None were to be put to work or, in the case of sheep, shorn. Again, this is a Madi custom as well.
Many of these customs are also practiced by other tribes in the Sudan. One Madi custom, though, is most striking in its obvious implication: All males are circumcised -- as I was -- on the 8th day.
When I was growing up, I did not know that any of these were "Jewish" customs. It was only when I began studying the Bible that the connection became clear. Most tribes who practice these customs do not know that "Jewish" means; they only know that these are the ways of their own forefathers.
Christian missionaries have long misinterpreted these "ways", especially missionaries from denominations which de- emphasize the "Old" Testament. Many labeled groups like Madi "pagan", "animist", or, incredibly, "without religion."
Today, the Islamic fundamentalists who rule the Sudan use similar terms to describe the tribes of South Sudan, including the Madi. Unlike the Christian missionaries of the past, however, the Islamicists know better. On more than one occasion, I was called "Jew" in a disparaging way by Muslims when I was living in the Sudan.
The current Islamic regime in Sudan is waging a jihad -- a war of extermination -- against the people and tribes of South Sudan. Almost 3 million of my people have been butchered in a genocide that is worse than anything the world has seen since the Holocaust. Those who know of this underreported slaughter rightly see it as religious in nature -- a war of Islamic imperialism against largely Christian South Sudan. It is also a cultural war of Arab- dominated culture against African culture. And part and parcel of African culture -- at least in this area of Africa -- are the remnants of Judaism.
For those would would like to see such remnants preserved, here is yet another reason to stand up for the brave people of South Sudan.