"When I came up and started floating, I was scared that something might happen to my father too, that we wouldn't reach the shore in time, or that I would get hypothermia," Mr Simancas said.
Luckily, the whale released him after a few seconds and the camera captured his father telling him "stay calm, stay calm".
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A kayaker has said he thought he was going to die when he was swallowed by a humpback whale.
The father and son both managed to get to shore safely after last Saturday's incident.
