Doug,
I have 4.3 of them, awesome snakes. They are essentially a black Gonyosoma oxycephala (Red-Tailed Green Racer/Ratsnake). They are so similar that they can even hybridize.
>>Are they all jet black all over?
Yes, but if you take them out in the sun they are more of a deep chocolate. In typical captive conditions, however, they are almost Indigo black.
>>How big do they get?
My adult male is still on the small size, but I understand they average just a bit bigger than the typical G. oxycephala. So about six feet.
>>What do they eat and how often?
One thing I like about Gonyosoma is that they don't have the crazy appetites of some other Asian Ratsnake types. I have a translated article from Europe and the author fed his adult females 2 mice per week. I feed my females a bit more than that.
They do deficate frequently and they are smelly.
>>Are they similar to other ratsnakes or do they require special care?
You must pay attention to humidity during shed cycles. That is the main difference to me. Don't make the mistake of keeping them warm 24 hours a day. I try to cool mine off at night.
>>But mainly how are they behaviorally? Can they be handled?.
I would never recommend a G. oxycephala or a G. janseni to someone who wanted a handleable snake. I make no effort to tame mine down so I'm not the best person to ask. However, I do know others with these species who handle their snakes.
I don't have any pictures of my adult male. Here are two pictures of my hatchlings and subadults. You may not know that they are born green and turn black between one and two years of age. The hatchlings are a beautiful emerald green. The first picture simply does not do justice to the color:
And here is a picture of a yearling starting to change color:
-----
Current snakes:
1.1 Gonyosoma oxycephala - (Silver/Yellow)
2.2 Gonyosoma oxycephala - (Green)
4.3 Gonyosoma janseni - (Black)
