A lot depends on how they are caught and handled. With some species such as lg. Crotalus just by holding behind the neck improperly can break their neck and kill them. These large snakes struggle violently and can break their own necks during the process. The Crotalus durrisus group are very susceptible to this happening for instance. Bitis atropos are delicate snakes to begin with.....
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Tom Crutchfield
www.tomcrutchfield.com