what makes you think you are doing something wrong? and are you SURE he's a dumerils? that cage seems a bit big to me but he will probably like it just fine. is the habitat made out of wood? sometimes viv's that are too big can be MUCH harder to maintain heat and humidity. do you have heat lamps on both sides or just 1? which side is the heat pad under? does the heat pad have a thermostat or a dimmer?
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i looked at the pics and he is DIFINETLY a dumerils, i have a big male dum also.
that cage, if i saw correctly, seemed alittle tall for a dumerils. they are ground boas and don't tend to need all the up and down room. also, is there substrate on the bottom? i couldn't really see.
this is nigma's viv. it is 4x2x2 and should last him the rest of his life. the snake might not MIND something your size, but he definetly doesn't need all the up and down room, and like i said it's harder to maintain proper heat and humidity. i have the feeling if i find a nice branch to attach to the inside of his cage somehow he might use it, but nigma doesn't mind his viv. i put a 100 watt infrared bulb on 1 side with a hide in the hot and the cold, and i mist him every few days or so.
here's my nigma photoshoot thread lol
http://www.ssnakess.com/forums/photo...igma-pics.html
i'll never know how the guy posted him on CL and let him go for free, he's super sweet.