my $string = '1 Cat 2 Dogs 3 Hamsters';
my @a;
push @a, $1 while $string =~ m/(\b\d+\s+\w+\b)/g;
use Data::Dumper; print Dumper \@a;
__END__
$VAR1 = [
          '1 Cat',
          '2 Dogs',
          '3 Hamsters'
        ];