Wild death adder males are sexually mature at 22 months, while females can reproduce when they reach 42 months of age. However, captive individuals can become sexually mature before reaching 20 months of age. In the wild, the mating usually occurs during spring, but females can reproduce only every second year. Males transfer sperm through organs called hemipenis, which they keep inside their bodies and expose only during copulation, which often lasts about one hour.
The gestational period in the common death adder can last from six to nine moths. A pregnant female often shows behavioral changes, including a voracious appetite during the early stages of pregnancy, restlessness and drinking more than usual in the last stages of the gestational period. Females often give birth when the weather is colder and more humid.
Common death adder females often give birth in fall. The number of young in a litter can vary widely, from two to 42, but is commonly between 10 and 20. Live young can vary in size, but average 6.5 inches long. Larger females tend to produce larger young. After birth, females do not feed or look after the litter.
Despite their name, the common death adder is becoming increasingly difficult to see in the wild, according to ABC Wide Bay. The number of death adders is decreasing in the wild especially due to loss of habitat and cane toad poisoning. Other threats to this species include road-kills and removal of rocks that provide refuge. Death adders are an important part of the food chain, feeding on mice and other small mammals and amphibians.