Snouted night adder

Geographical Origin and Habitat: This species is native to the central-eastern and southern regions of Africa, extending from countries like Tanzania and the Democratic Republic of the Congo down to South Africa. It primarily inhabits open savannas, moist grasslands, light woodlands, and sandy coastal zones. It is commonly found near temporary or permanent water sources, such as rivers, marshes, and ponds, where the density of amphibians, which constitute its main food source, is high.

Taxonomy and Genetics: Causus defilippii belongs to the family Viperidae, subfamily Causinae, and the genus Causus, commonly known as night adders. This genus differs from other vipers by having large symmetrical shields on the head, similar to those of colubrids, and exceptionally elongated venom glands that extend along the sides of the neck, an anatomical feature unique and highly interesting from an evolutionary standpoint.

Behavior and Habits: Despite the common name of night adders, many species of this genus, including Causus defilippii, show marked diurnal or crepuscular activity. It is a predominantly terrestrial and fossorial reptile that loves to hide under leaf litter, stones, or in abandoned burrows of small mammals. When threatened, it inflates its body, produces a loud hiss, and can strike rapidly, although its venom is considered less toxic than that of other African vipers.

Morphology: The most obvious morphological feature is the short and distinctly upturned snout, a useful adaptation for digging in soft soil. The body is stocky and cylindrical, with an average length ranging between 35 and 45 centimeters, rarely exceeding 50. The dorsal coloration varies from light gray to reddish-brown, adorned with a series of dark arrow-shaped or inverted 'V' markings along the back and a characteristic dark 'V' on top of the head.

Terrarium Setup: A terrarium for an adult specimen must measure at least 80x40x40 cm. Being a terrestrial and partially fossorial species, it is essential to provide a deep layer of soft and draining substrate, such as a mixture of peat and sand or dry coconut fiber, to allow burrowing. There must be plenty of dry hiding places at ground level, such as cork bark, low branches, and stable rocks to create shaded areas and secure retreats.

Lighting and Heating: Heating must be provided via a heating spot lamp or a protected radiant panel to prevent burns. The temperature during the day must range from a cool zone of 24-25 °C to a hot basking spot of 30-32 °C. During the night, the temperature can drop to 20-21 °C. Installing a low-output UVB source (2.0 or 5.0) active for 10-12 hours a day is recommended to support circadian cycles and the reptile's general well-being.

Humidity and Hydration: Humidity should be kept at medium levels, around 50-60%, with a slight increase during the shedding period. It is important to avoid constantly wet substrate which promotes dermatological infections. A bowl of fresh, clean water must always be present, large enough for the animal to soak if it wishes, but positioned in the cool zone to prevent excessive evaporation.

Feeding and Supplementation: In the wild, the diet consists almost exclusively of amphibians (frogs and toads). In captivity, accepting rodents can be very difficult and often requires a gradual transition using scenting techniques of mice with amphibian skin. Young specimens should be fed every 5-7 days, adults every 10-12 days. Supplement the prey with calcium and vitamin D3 once a month to prevent bone deficiencies.

Compatibility: Causus defilippii must be housed strictly alone. Co-housing multiple specimens in the same terrarium is a source of stress and increases the risk of territorial conflicts or competition for thermal and food resources. Furthermore, being a venomous animal, single management is an essential safety requirement to facilitate routine maintenance operations.

Health and Common Diseases: The main risks are related to food refusal (anorexia), common if amphibians are not offered, and dehydration. High humidity levels or poor ventilation can cause bacterial dermatitis and respiratory infections. Metabolic bone disease (MBD) can occur in the absence of adequate calcium and UVB supplementation. Handle the reptile only when strictly necessary and with the aid of herpetological hooks.