Rhombic night adder

Geographical Origin and Habitat: Causus rhombeatus is a venomous snake widely distributed throughout sub-Saharan Africa. Its geographic range extends from South Africa northward through East and Central Africa to Sudan, Ethiopia, and West Africa. It primarily inhabits open, moist environments such as grasslands, wooded savannas, forest edges, swamps, and riparian areas along rivers and lakes. It adapts well to disturbed environments, frequently visiting damp gardens, pastures, and plantations where it finds an abundance of its preferred prey. It avoids dense rainforests and arid deserts.

Taxonomy and Genetics: Belonging to the family Viperidae, subfamily Causinae, genus Causus. It is considered one of the most primitive vipers in existence, an evolutionary trait evident in its head covered with large symmetrical shields rather than small fragmented scales as in typical vipers (Viperinae). Genetics: it features exceptionally long venom glands that extend along the sides of the neck deep into the body cavity for several centimeters, a unique anatomical feature shared with only a few other snakes.

Behavior and Habits: It is a terrestrial species, primarily active during crepuscular and nocturnal hours, although it may bask in the sun during the day. It shows an active hunting behavior, moving around to search for prey (especially toads and frogs) which it locates using vision and scent. When disturbed, it assumes a defensive posture by raising the front of its body, flattening its neck, and hissing loudly. If further provoked, it can strike quickly and repeatedly, though its venom is of low toxicity to humans.

Morphology: It has a moderately cylindrical and robust body with a short tail. The head is relatively small, indistinct from the neck, and covered with large, shiny cephalic shields. The eyes have round pupils, unlike the vertical slit pupils of most vipers. Adults measure on average between 60 and 90 centimeters. Dorsal coloration ranges from light gray to olive-brown, decorated with a series of 20-30 large, white-edged dark brown rhombic spots. A prominent inverted V-shaped dark marking is present on the head.

Terrarium Setup: Captive husbandry requires a secure, escape-proof horizontal terrarium measuring at least 80x50x40 cm for a single specimen. The enclosure must be equipped with a safety lock. The ideal substrate is a mixture of peat and sand or coconut fiber 5-8 cm deep, kept dry on the surface but slightly damp in the lower layers. Include dry hides such as cork bark and a humid hide with sphagnum moss. A water bowl large enough for the snake to submerge completely must be provided.

Lighting and Heating: Requires a 12-hour light-dark cycle. The use of a low-intensity UVB bulb (2-5%) is recommended to simulate daylight and aid vitamin synthesis. Heating must be provided via a heat mat or heat cable positioned under one-third of the terrarium and connected to a thermostat, ensuring a thermal gradient with a hot zone of 28-30°C (82-86°F) and a cool zone of 24°C (75°F). At night, the temperature can drop to 20-22°C (68-72°F).

Humidity and Hydration: Humidity must be kept at moderate levels, between 50% and 60%. Lightly mist once a week, especially before the shedding cycle to facilitate skin shedding. Ventilation must be abundant to prevent stagnant humid air that would promote the proliferation of fungi and bacteria on the snake's skin.

Feeding and Supplementation: A dietary specialist. In the wild, it feeds almost exclusively on amphibians (toads of the genus Sclerophrys and frogs). In captivity, it can be difficult to transition them to rodents (mice), although many specimens accept live or thawed mice scented with an amphibian. Feed adults every 10-14 days. Special supplementation is not needed if fed well-gut-loaded prey.

Compatibility: A solitary species that must be housed individually. Handling must be kept to a minimum and performed only using herpetological hooks and long tongs to prevent accidental bites. Although the venom is less potent than that of other vipers, it still causes severe local pain, swelling, and lymphadenitis, requiring professional and safe handling.

Health and Common Diseases: The main risks include food refusal if amphibians are not offered, intestinal parasites (particularly common in wild-caught specimens), respiratory infections due to low temperatures, and skin dermatitis if the substrate remains wet. Maintaining hygiene by promptly removing waste and regularly cleaning the water bowl is essential.