$phrase = "NoMatch cowsCanFly sheepAreVeryCool NoMatch";

$phrase =~ s{
               \b
               (
                  [a-z]+
                  (?:[A-Z][a-z]+)+
               )
               \b
            }{
               my $word = $1;
               $word =~ s/([A-Z])/"-" . lc($1)/eg;
               $word;
            }gex;

print $phrase, "\n";