Kouya no Hanayome

The time is the Stone Age. Before a tribe living in the wastelands, a woman drifts ashore. Their elder thus decides to take her in as the future bride of their only male. Hunting mammoths, singing, dancing, taking a nap, occasionally going to hot springs: this is the laid-back daily life of cute Stone Age girls living in the harsh period leading up to the Ice Age! (Source: Futabasha, translated)