I know that
N. philipinensis is the most venomous of the bunch, but how do the rest pile up?
It’s often claimed that
N. nivea is second, but this is just not true. According to Brown (1973), the Cape cobra has an SC (subcutaneous) LD50 (median lethal dose) of 0.72 mg/kg (this is also the figure which is listed by Dr. Bryan Grieg Fry of the Australian Venom Research Unit at the University of Queensland). Another figure for
Naja nivea was 0.81 mg/kg. Its arguably the most venomous of the "true" (
Naja ssp) African cobras, but definitely not second in the world. To compare, Brown claims an SC LD50 of 0.2 mg/kg for the Philippine cobra (
N. philippinensis) - which is the most toxic Naja species.
Naja oxiana (Caspian cobra, Central Asian cobra) is an highly venomous
Naja species with an LD50 of 0.4 mg/kg (nearly twice as potent drop for drop as
Naja nivea). A LD50 of 0.53 mg/kg was given for
Naja atra (Chinese cobra) - I actually have a scan of this which you can see here (left page, top paragraph):
http://i55.tinypic.com/21jvc7p.jpg
Another figure for the Chinese cobra lists the LD50 at 0.57 mg/kg. Engelmann & Obst (1981) gave a figure of 0.67 mg/kg for the Chinese cobra, which still puts it ahead of the Cape cobra.
Naja naja (Indian cobra) is sort of all over the place in terms of an LD50 value. I’ve seen a range from 0.45 mg/kg to 1.0 mg/kg. Brown listed the LD50 of the Indian cobra at 0.80 mg/kg, which makes the Cape cobra slightly more venomous. I believe this to be correct based on mortality rates, which tend to be higher within Cape cobra victims.
Other Naja species’ SC LD50 values:
N. nigricollis (black-necked spitting cobra) is 2 mg/kg and
N. haje (Egyptian cobra) is 1.15 mg/kg.
Some I.V. LD50 values (note: IV LD50’s tend to be much lower than SC LD50’s): 0.29 mg/kg for
N. atra (Chinese cobra), 0.37 mg/kg for
N. kaouthia (Monocled cobra), and 0.6 mg/kg for
N. melanoleuca (Forest cobra). The Forest cobra can yield up to 500 mg of venom per bite! (Spawls & Branch, 1995)
Another overlooked species is
Naja samarensis (Samar cobra). This is the closest relative to the Philippine cobra and Wolfgang Wuster has claimed that he had heard of 1 bite which resulted in severe neurotoxicity, similar to bites seen from the Philippine cobra. The composition of its venom is one that is just seems virulently toxic. I tend to believe the island bound cobras are probably the more venomous species (ie.
N. philippinensis, N. samarensis, N. sputatrix, etc), but this is just a guess.
From what we know,
N. philippinensis is most venomous and second is
N. oxiana, followed by
N. atra.
Anyone else has some input? This could be a very nice and informative discussion.
Hybrid Mode
