The local wild life where I live had a habit of raiding my
dustbins, presumeable looking for a nice bite to eat. They have
the technique of knocking over the trash can and then ripping the
black trash bag inside after the trash can lid pops open.

Does anyone have a good way at keeping the trash can lid shut when
the trash can falls over. I am sort of tired in picking up all the
rubbish that is scattered everywhere.

Assuming a regular metal can with handles: I used to run a chain from
handle to handle and attach it to itself with a clip.