This snake is dangerously venomous. As it is with all mambas the elongate, flat-sided head is often referred to as coffin-shaped. When stressed an eastern green mamba may elevate the forward portion of its body and flatten its neck into a narrow but discernible hood. They can and may gape and hiss, but are less likely to do so than the black mamba.
Hatchling (they are about 15 inches long when emerging) and juvenile green mambas can be kept in terraria of 20 to 50 gallon capacity. An adult will require a minimum of a 100 gallon capacity or larger cage. The terrarium should be well ventilated and have a foolproof locking top. Fortunately, most captive green mambas will readily accept a small hidebox with a locking door (called a trapbox). They prefer that the box be situated in an elevated position. Once the snake is securely locked in the box, the box and the snake it contains, can be safely moved. The trapbox will be most readily and continually accepted if it is located in a quiet area of the cage and is always in the same place. Sturdy, well anchored, horizontal climbing limbs will be readily used. To facilitate the handling of this dangerous snake the cage design should be simple but effective.
Certainly, once the snake is inside the careful closing and locking of the trapbox door and then the moving of the box is the safest of all methods. Barring that, the use of a clamp stick is the next safest method, but due to the speed, agility and size of this dangerous snake even the deft use of a clampstick is an accident in waiting. Seek the help of an experienced elapine keeper, heed all admonitions given.
A temperature gradient of several degrees should be provided. At the cool end of the terrarium a temperature of 74 degrees Fahrenheit is suitable but the warm end should be 84 to 86 degrees. A basking hotspot of 94 to 100 degrees will be utilized during thermoregulation.
Cypress, fir, aspen chips or bark shards are excellent choices for a substrate. After locking your mamba in its trapbox feces can be removed with a small, long handled shovel. A large water bowl (kept scrupulously clean) should always be provided. The snakes will both drink, and if the receptacle is large enough, soak in the bowl. Keeping your snake well hydrated and its cage humidity fairly high will help assure complete, healthy sheds.
Green mambas have a very high metabolism. They will require feeding twice a week. Hatchlings should be fed pinky mice. As the snake grows, so, too, should the size of the prey items increase. Adult green mambas can readily ingest and speedily digest a half to three quarter grown rat.
These snakes are active year around. It is probable that climatic cues such as photoperiod, ambient temperature, and relative humidity stimulate ovulation. This oviparous snake produces between 8 and 15 eggs in a clutch.