If you add print "@_\n"; between sub zivad { and my $animal = shift;, perl will tell you exactly what is in @_. In this case you'd see mago (which comes from print zivad('mago');).

%list can be accessed anywhere after my in the snippet you posted, and that's just what your subroutine is doing.

This is what happens step-by-step

• the subroutine call zivad('mago') puts "mago" into @_ and starts running the code in the subroutine zivad.
• my $animal = shift takes the first element of @_ (which will be "mago") and puts it in to $animal.
• my $list = $list{$animal} || die  "no  animal" does a few things:
  • Looks up $animal in %list and returns the value associated with "mago" ("ia-ia").
  • If the animal wasn't in %list, the script will stop (die) with the "no animal" error message.
  • The value returned from %list is assigned to $list.
• return $list returns "ia-ia" to the print that displays it on the screen.