Most species of Toxicocalamus are relatively small, the largest specimen known being the holotype of the recently described Toxicocalamus ernstmayri, which measures 1.1 m (43 in) snout-to-vent length (SVL) and 1.2 m (47 in) in total length (TTL). The second longest is the holotype of T. grandis, which measures 0.88 m (35 in) SVL, 0.98 m (39 in) TTL. Most species are under 0.80 m (31 in) TTL, and several are the thickness of bootlaces. In general females have longer bodies than males, but much shorter tails.
Members of genus Toxicocalamus are venomous, with fixed front-fangs (a dental arrangement known as proteroglyphous), but are not known to be a threat to humans, being unaggressive, of modest size, and secretive. However, the venom of T. longissimus is believed to be fairly toxic, since it contains three-finger toxins (3FTx), Type-I phospholipase A2 (PLA2) and snake venom metalloproteinase (SVMP),[2] while T. buergersi possesses long venom glands than extend backwards into the body cavity.[1]
Although most species of Toxicocalamous are believed to be diurnal, they are fossorial, or semi-fossorial, in habit and rarely encountered.[3]
Many species of Toxicocalamus are localised in their distribution and associated with particular islands or mountain ranges. Several species are poorly known, with four known only from their holotypes. Toxicocalamus is probably not closely related to the Australian Elapidae, being endemic to the island of New Guinea, northern coastal offshore islands, i.e. Seleo Is. (Sandaun Province, PNG); Walis Is. and Tarawai Is. (East Sepik Province, PNG), and Karkar Is. (Madang Province, PNG), and the archipelagoes of Milne Bay Province to the southeast, i.e. d'Entrecasteaux Archipelago (Goodenough Is., Fergusson Is., and Normanby Is.), Woodlark Is., and the Louisiade Archipelago (Misima Is., Sudest Is., and Rossel Is.).[3][4][5]
The prey of snakes in the genus Toxicocalamus appears to consist almost entirely of earthworms, particularly the giant earthworms of the Megascolecidae,[5] hence the adoption of the term "worm-eating snakes" for species within this genus.
In common with other tropical elapids, Toxicocalamus is believed to reproduce by oviparity, with clutch sizes of 3–7 recorded, dependent on species and size of the female.