no lists of top ten venomous snakes don't belong in any encyclopedia including wikipedia these kinds of lists belong maybe in a children's book venom composition is not static even within a single individual it will vary in quantity and relative proportions of components over time greater variability in components is seen between individuals of a species greater still between species further venom continues to evolve often very rapidly so there may be wide variations in venom composition and toxicity within a single species over its geographic range this is especially true for widely distributed species and may cause problems in antivenom effectiveness factors involved in the variation of venom and its toxicity include diet habit variability seasonal changes geographical location age dependent variability gender dependent sexual variability altitude and the list goes on then you've got the research methods used this can be critical as some snakes produce many venom components but eject them sequentially rather than as a uniform mixture the immediate fate of the venom after collection is important particularly in relation to environmental conditions that might denature certain components the storage of the venom is also vital and exposure to heat may cause damage to certain toxins prolonged storage in liquid form may damage others pooled venom may introduce many variabilities because each pooled batch of venom will contain venom from different specimens compounding both intra individual and intra specific variability there are many potential variables in such research that may affect comparability and interpretation of results the choice of test animal may be crucial because each species may respond differently including humans the choice of route is also critical the standard test of toxicity is the ld mice are most commonly used the ld remains the most universal standard for determining and comparing toxicity of venoms as an example the rough scaled snake tropidechis carinatus has a much less potent venom than the tiger snake notechis scutatus on ld testing in mice yet clinically the two venoms are virtually identical in the type and severity of effects on envenomed humans there are many examples just like this across all species the black mamba is not the most venomous snake species in the world but it untreated human moratality rates are and produces death in the most rapid time to compare the many banded krait has a more potent venom on mice but doesn't produce the same devastating effects on humans the way the black mamba does many more examples are readily available mice aren't humans yes they may give us an idea on toxicity but they aren't the same as humans talk to me