www.elasmo-research.org/education/white_shark/sensory_bio.htmAbsolutely fascinating information at the site above, goes through the whole sensory spectrum for GWs.
In short, they can see in colour and have excellent vision, in fact all of their senses are extraordinary.
They are also thought to be quite intelligent, based on the level of sensory input that they deal with and the observed interaction between each other. rather than just being eating automatons.
They can see us, hear us, smell us and feel our motion in the water long before we're even aware that they are around.
So what makes the difference between one cruising by and one day having no interest in people, to the next time that it decides to take a bite?
Could it be similar to us, in that we're more likely to be tempted to have a bite of junk food due to the convenience of the drive-thru, the longer since when we last had a proper meal?
But based on the info at the site above, there must be some way to exploit their sensors to discourage the big guys from having a bite before they get close enough to do so.
The sea otter example was interesting...