How did Udmurt sacrifices to sky gods differ from sacrifices to spirits of the earth?

In Udmurt religious practice, sacrifices are categorized by an "upward" and "downward" orientation, which dictates the ritual requirements and the nature of the offerings.1

• Sacrifices to Sky Gods: These are directed "upward" toward the god of the sky (such as Inmar) and certain nature gods. These rituals involve the sacrifice of white animals and are performed in deciduous groves. During these ceremonies, the direction of prayer is toward the south.1
• Sacrifices to Earth Spirits: These are directed "downward" toward the departed and the guardian spirits of the earth. These rituals involve the sacrifice of black animals and are performed near conifers. During these ceremonies, the direction of prayer is toward the north.1

This formal system reflects a broader distinction in Udmurt worship, where the choice of animal color, location, and orientation serves to differentiate between the celestial realm and the terrestrial or ancestral spirits.1