They are a closed species.
Brief info on Nocts. http://www.furaffinity.net/journal/6930054/

Banshee! The first of the Halloween Nocts.

Adoption Cost : $10 USD
What you get, the full sized ref sheet and the two individual image separately.
You will also gain access to any Noct bases in the future that can be made to make art of your own Noct or for other Noct owners.
Simply comment to claim.

Some rules...
1. You may not resell the character for more than you paid unless it includes extra art. I must be made aware of the resale.
2. You can change his/her gender and hairstyle to whatever you wish, add piercings, revamp his/her taste in clothing.
3. Credit me for the original art and the race please.