If at least one animal is carrying a piece of its prey in its mouth.
return animal ;return mouth of #1 ;return prey ;return piece of #3 ;return #1 carrying #4 in  #2 ;return the  number of  #5 ;return if  #6 is at least one
['select', 'project', 'select', 'project', 'filter', 'aggregate', 'boolean']