We probably do have it (a sixth sense), but we probably have learned to not listen to it. We have reasoning and intellectualizing, and other things that conflict us when "RUN" is all that we should be thinking. Animals were all able to swim and run, (good thing they were not fenced or tied). Animals also did not stop to think "whats going one here" they used every available moment to run the other way. They also were not conflicted over whether to try and save someone else or grab some precious belongings. All this helped the animals while some people were walking on the extended beach wondering what it meant.
I do Fish ALOT by the way - I caught 10 Crappies 2 days ago that are 14-15" long (big ones!).
animals heard and felt vibrations, sounds not noticed by humans. sometimes it doesn't help them, like when deer run toward a moving car.