we have a collie greyhound lurcher when we go to the beach we chuck a biggish stone for her and she chases after it then drops it on the sand and starts digging around it and flicks it out with her front legs she then gets the stone again and drops it back were she was digging and then does the same again untill she got a big hole she lay in the hole have a rest and then carry on again with the same stone digging and flicking it out again