Hydrophis belcheri
Belcher's sea snake, which many times is mistakenly called the "hook-nosed sea snake" ("Enhydrina schistosa"), has been erroneously popularized as the most venomous snake in the world, due to Ernst and Zug's published book "Snakes in Question: The Smithsonian Answer Book" from 1996.
Associate Professor Bryan Grieg Fry, a prominent venom expert, has clarified the error: "The hook nosed myth was due to a fundamental error in a book called 'Snakes in question'. In there, all the toxicity testing results were lumped in together, regardless of the mode of testing (e.g. subcutaneous vs. intramuscular vs intravenous vs intraperitoneal). As the mode can influence the relative number, venoms can only be compared within a mode. Otherwise, its apples and rocks.". Studies on mice and human cardiac cell culture shows that venom of the inland taipan, drop by drop, is the most toxic among all snakes; land or sea. The most venomous sea snake is actually Dubois' seasnake ("Aipysurus duboisii" ).
Rat snake
Rat snakes (or ratsnakes) are members – along with kingsnakes, milk snakes, vine snakes and indigo snakes – of the subfamily Colubrinae of the family Colubridae. They are medium to large constrictors and are found throughout much of the Northern Hemisphere. They feed primarily on rodents and birds. With some species exceeding 2.5 m (8 ft) in total length, they can occupy top levels of some food chains. Many species make attractive and docile pets and one, the corn snake, is one of the most popular reptile pets in the world. Other species can be very skittish and sometimes aggressive, but bites are rarely serious. Like nearly all colubrids, rat snakes pose no threat to humans. Rat snakes were long believed to be completely nonvenomous, but recent studies have shown that some Old World species do possess small amounts of venom, though the amount is negligible relative to humans.