my %SWITCH = (
   CAT      => 0b00001,
   DOG      => 0b00010,
   HAMSTER  => 0b00100,
   FERRIT   => 0b01000,
   FISH     => 0b10000);
   
my $petInput = 2;
my @PETS;
   
my $binPet = unpack("B32", pack("N", $petInput));
$binPet =~ s/^0+(?=\d)//;   # gets rid of leading zeros

printf "%s%bn%s", "\n", $binPet, "\n";

# at this point $binPet unfortunately contains "0b1010"
# rather than 0b10 as expected, so I'm doing something wrong
# in my pack/unpack apparently

for (keys %SWITCH) {
	if ($binPet & $SWITCH{$_}){push (@PETS, $_);}		
}

foreach (@PETS){print $_."\n";}