The Court of Appeal concludes that substantial evidence supported the juvenile court’s findings that the Department made an adequate inquiry and that the ICWA did not apply. Mother denied any Indian ancestry and did not provide the Department with any names and contact information for extended family members, constraining the Department’s ability to conduct an exhaustive inquiry. Father’s inconsistent statements regarding possible Indian ancestry did not create a “reason to believe” the children were Indian children, and even if a duty was triggered, substantial evidence indicated the duty was satisfied.