What is one reason some Maori ancient carvings survived?

Question

The Maori used durable materials such as bone and stone to make their carvings.
The carvings were religious in nature, so the Maori went to great lengths to pass them down from generation to generation.
The carvings were buried deep under shelters and discovered hundreds of years later.
The Maori sometimes placed the carvings in swamps during times of threat.

Answer 1

The Maori sometimes placed the carvings in swamps during times of threat.