How do bats make noise when they are threatened?

When threatened, bats often emit high-frequency echolocation calls or distress calls to communicate their fear or to deter potential predators. These vocalizations can serve to alert other bats in the area about the danger. Additionally, some species might produce louder, more aggressive sounds to assert their presence and ward off threats. The specific type of noise and its purpose can vary depending on the species and the situation.