Because that is the most efficient shape for materials used.
They Were Wikiups
The coahuiltecan tribes used wikiups as shelter.
They're called Wikiups
They Were Wikiups
They lived in wikiups and buffalo-hides, which was their alternative.
Usually teepees, but sometimes wikiups, or small huts.
South Texas is where the Coahuiltecans lived
The Wampanoag homes were wikiups, a sort of rounded dome made of twigs.
Apaches were a migratory people. Depending on the location and available materials, Apaches lived in teepees, mud hogans or wikiups.
Longhouses and wigwams for North east tribes, Tipis for the Plains tribes, Wikiups for the southwest tribes, log cabins for the Cherokee, etc etc... what tribes do you mean specifically?
The Coahuiltecans lived in southern Texas on both sides of the Rio Grande River. Some tribes also lived in Mexico. Much of the population of Coahuiltecans was wiped out by smallpox.
The Wampanoag homes were wikiups, a sort of rounded dome made of twigs.