In my experience they just enjoy the free ride while traveling towards open sea. Like a skater hanging from a pickup. They save a lot of energy in the process p

In my experience they just enjoy the free ride while traveling towards open sea. Like a skater hanging from a pickup. They save a lot of energy in the process probably. They seem also to enjoy to watch the humans while doing that. One of the few wild big animals that will freely approach humans and look you in the eye.