c:\@Work\Perl\monks>perl -wMstrict -le
"use autodie;
 no  autodie qw(open close);
 ;;
 use List::MoreUtils qw(uniq);
 ;;
 use Data::Dump qw(dd);
 ;;
 my $file = qq{bird beak\n}
          . qq{bird beak\n}
          . qq{bird claw\n}
          . qq{bird wings\n}
          . qq{bird feathers\n}
          . qq{snake fangs\n}
          . qq{snake scales\n}
          . qq{snake fangs\n}
          . qq{snake tail\n}
          ;
 print qq{[[$file]]};
 ;;
 open my $fh, '<', \$file or die qq{opening ram file: $!};
 ;;
 my %hash;
 while (my $line = <$fh>) {
   my $parsed =
   my ($animal, $organ) =
   $line =~ m{ \A ([[:alpha:]]+) \s+ ([[:alpha:]]+) \Z }xmsg;
   ;;
   die qq{bad line '$line'} unless $parsed;
   ;;
   push @{ $hash{$animal} }, $organ;
   }
 ;;
 close $fh or die qq{closing ram file: $!};
 ;;
 @$_ = uniq @$_ for values %hash;
 dd \%hash;
"
[[bird beak
bird beak
bird claw
bird wings
bird feathers
snake fangs
snake scales
snake fangs
snake tail
]]
{
  bird  => ["beak", "claw", "wings", "feathers"],
  snake => ["fangs", "scales", "tail"],
}