Boaguy,
Viper boas are great captives. They are usually pretty hardy once thier requirements are met.
Most viper boas can reach about three feet or so. they aren't so long as they are wide...they truly are built like a viper. And many act like vipers, too...don't buy one expecting it to be tame, especially if you buy a wild-caught adult. some calm down but I'd say they are in the minority.
Viper boas like moderate to high humidity. I keep my candoia boas on cypress mulch, as this retains humidity really well. They love to soak in water so make sure to add a water dish that will allow them to do so. i keep my temperature gradient at about 70-83. They have a relatively slow metabolism so feeding more than once every 10 days is not necessary.
Joe
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2.2 Solomen Island ground boas
0.1 Solomen Island tree boa
1.0 green tree python
1.0 jungle carpet python
2.0 coastal carpet python
1.0 Boa constrictor imperator
0.1 Borneo short-tailed (blood) python
0.0.1 CB Florida banded water snake
1.0 albino Burmese python