Large saltwater crocodiles can stay underwater for at least one hour because they can reduce their heart rate to 2-3 beats per minute. This means that crocodiles can wait underwater until they see prey, or if people are using the same spot regularly, the crocodile can wait underwater until someone approaches the water's edge. A voluntary dive normally lasts no longer than 15 minutes, and usual dive times are around 4 to 6 minutes. The smaller the crocodile, the lower its capacity to survive without oxygen underwater.

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