BUKAVU, Democratic Republic of Congo — It’s around 6 in the morning and the sun is slowly rising, a clear sign that Cesarine Maninga must leave. In one practiced movement, she straps a 50-kilogram sack of charcoal to her back, tosses the rough rope around her head and trudges off toward Bukavu, capital of South Kivu province in eastern Congo.

Ms. Maninga, 43, is just one of hundreds of women who ply this trade each day, lugging loads of up to 100 kilograms, or 220 pounds. On this morning, she hopes to sell makala — dry charcoal used for heating and cooking. She will walk almost 10 kilometers, or about six miles, with the heavy load, a trek she makes at least twice a week.

“I don’t have a choice,” she said, bitter resignation in her voice. “I have to feed my family” — 11 children, and an unemployed husband.

Women like Ms. Maninga are a common sight on the streets of Bukavu, striking not for their looks but for the outsize burdens they carry. In French, they are les femmes transporteuses; in Kiswahili, they are called babeba mizigo. Whatever the language, the job is the same: Female carriers are human pack horses.