I have grown tomatoes for a couple of years without any pest issues, not even birds bother with them.

This year, I grew two SunGold 3 feet from a fence where squirrels frequent passing by. And as soon as the tomatoes turned a bit yellow, they disappeared without a trace. There were no visible damages to the plant or pieces of left-overs on the ground.

Is this squirrels' doing? If so, how do I stop them?