Two whale-watching kayakers were nearly crushed by one of the same peaceful, sea-dwelling mammals they sought this week near Monterey Bay, California.

The video below shows the pair of British vacationers paddling on languid Pacific waters - when a humpback whale breaches the surface and nearly body slams them. Unlucky to have been dragged underwater by the whale's weight after their kayaks capsized, but lucky to be alive and unharmed, they get a sharp reminder why wild animals should be respected and given their space.

Humpback whales might be beautiful creatures, but they also weigh 50 tonnes. Just keep that in mind the next time you're trying to get up-close and personal on a whale-watch.

Here's hoping you never see a whale the way this couple did this week: