As their common name suggests, these are riverine snakes. What is noteworthy about them is their fairly peaceful nature: if disturbed B. annulata usually simply swims away (if in or able to reach water), and no bites are apparently known. They are oviparous.
|Scientific Name||Common Name||Distribution||Size||Notes|
|B. annulata||(Banded) Water Cobra||Guinea, Congo-Brazzaville, Cameroon, Gabon, Burundi, Rwanda, Tanzania, Dem Rep Congo
|Max TL 2.7: avg TL 1.4-2.2m||A peaceful snake, good swimmer and diver, associated with lakes and rivers in forest and wooded savanna. Despite this preference for tree cover it will venture out on to open beaches and sand bars. When inactive it may shelter in shoreline rock formations, or holes in banks, trees or root clusters, or may use man-made cover such as huts and other buildings, jetties and the like. Diet recorded as fish, SHDA suggest it might also take amphibians. Can be confused in the field with the colubrid snakes of the Grayia genus. O'Shea notes the species as diving up to 25m deep and remaining submerged for up to 20 minutes and likens them to a freshwater seasnake but having terrestrial agility, unlike the latter. The hood can be spread even underwater. Bitees are most likely from half-drowned cobras being pulled from fishermen's nets [O'Shea]. Scalation details: head shields regular and large; 7 supralabials, of which 3rd & 4th supralabials contact eye; 8-9 infralabials; 1 preocular, 2 postoculars, 2 anterior temporals; nuchal scales keeled; body scales imbricate; 35-49 rows at midbody; 323-452 ventrals, scarcely wider than adjacent body scales and mostly undivided. Other: 5-6 solid maxillary teeth follow fang; head very small; anterior part of body slender, posterior part deep and greatly compressed. Coloration: see subspecies details, but generally ground colour changes and number of bands increases towards north and west of range. Reproduction: no details available [SOURCE: SHDA, O'Shea].|
|B. a. annulata||Western part of the range, including E Dem Rep Congo and poss. Rwanda||Scalation details: 23 scale rows at midbody. Coloration (E Dem Rep Congo specimens, possibly also Rwandan): overall warm brown or orange-brown; wide jet-black transverse rings run length of body; ventrally bright orange [SOURCE: SHDA].|
|B. a. stormsi||Storm's Water Cobra||Tanzania (Lake Tanganyika)||Scalation details: 21 scale rows at midbody. Other: longer tail than in annulata. Coloration: overall grey-brown, brown or yellow-brown, darkening towards tail; tail is glossy black; 2-3 narrow but distinct black bars (sometimes rings) on nape; head scales may be black edged; black blotch on side of neck may be present; ventrally pale cream or yellow. O'Shea suggests it may be endangered, partly through drowning in fishermen's nets. [SOURCE: Schmidt & Noble, SHDA, O'Shea].|
|B. christyi||Christy's Water Cobra||Republic of Congo, Democratic Republic of Congo|| ||Found along the lower Zaire River: apparently little known even today [SHDA]. Scalation details: nostril very large, pierced in single nasal; 1 preocular, 2 postoculars; temporals 1-3. 7 supralabials, of which 3rd & 4th contact eye; 8 infralabials, of which 4 contact anterior chin shields; dorsal scales smooth, in 17 rows at midbody; 206 ventrals; 69 paired subcaudals. Other: head wider than that of B. annulata; posterior half of body strongly compressed, with median row of transversely widened dorsal scales; eye small with round pupil; maxillary bone extends forward as far as the palatine; pair of large grooved poison fangs followed by 2-3 small teeth; anterior mandibular teeth longest. Coloration: overall black; neck has irregular yellowish crossbands, becoming more indistinct posteriorly until they disappear after anterior quarter of body; throat and chin yellow; head brownish, dorsally darker and laterally lighter. Reproduction: no details available [SOURCE: Schmidt & Noble].|
Field Guide to the Reptiles of East Africa by Stephen Spawls, Kim Howell, Robert Drewes and James Ashe, Academic Press London 2002.
Contributions to the Herpetology of the Belgian Congo, Karl P Schmidt and G K Noble, Society for the Study of Amphibians and Reptiles, 1998 (reprint of 1919-1923 papers).
Venomous Snakes of the World, Mark O'Shea, New Holland, 2008 edition. Useful overall guide to venomous snakes, few anatomical details but venom is briefly described for each species.