The Mazumbai warty frog is a ground dwelling as well as climbing species. There is no aquatic tadpole stage, and instead the embryonic and larval development up to metamorphosis takes place within the eggs. This species therefore breeds by “direct development”. The eggs are deposited in dark, damp locations, as is the case with their close relatives, the globular African rain frogs (of the genus Breviceps), which lay their eggs in underground chambers, where they develop into froglets. The short arms and rotund body of the Mazumbai warty frog is likely to render amplexus (the mating embrace) rather difficult. Added to these unfavourable body dimensions is the fact that the males, who must grasp the female from behind, are by far the smaller sex. Although little is known of the breeding habits of the warty frogs, it is possible they are similar to that of the African rain frogs. The highly bulbous, short-limbed African rain frogs manage their amplexus (mating embrace) by being very sticky – the male literally sticks himself to the female so that he can remain in an appropriate position to fertilise her eggs as they are released. The Mazumbai warty frog is also known to be very sticky.
Mazumbai warty frogs commence their mating calls when the rainy season starts, generally at night between the hours of 20:00 and 23:00. The males climb into low bushes and other vegetation where they start to call. It has often been observed that calling males position themselves vertically on small trunks, from 0.5–2 m off the ground. Their warty, camouflaged appearance meant that they were initially mistaken for notches in the trunks. They have also been found calling at the junction of branches. The call is a long trill composed of 8–18 notes, at an average call duration of 126 milliseconds. There is an average of 5.44 pulses per note and the intensity of the dominant frequency is around 1.84 KHz, which is significantly lower than that of its sister species Callulina kreffti in the East Usambara Mountains.
Through the examination of the stomach contents of one specimen of this species, the Mazumbai warty frog is known to feed on relatively large arthropods (Hemiptera or bugs, Orthoptera or crickets, and Diplopoda), and nematode worms.
The Mazumbai warty frog is found in damp mountain forests with dense undergrowth, and is presumed to be intolerant to habitat degradation. It is both terrestrial and partially arboreal.
There is no information on the abundance of this species.
This species is thought to be in decline by the IUCN Red List of Threatened Species.
The Mazumbai warty frog is listed as Endangered in the IUCN Red List of Threatened Species because it has an area of occupancy and extent of occurrence of less than 500 km sq., within which remaining habitat is severely fragmented and declining in both quality and overall area.
Habitat loss due to smallholder agriculture is likely to be a threat to unprotected forests within the range of the Mazumbai warty frog. Habitat degradation may also be a threat through both logging activities and extraction of firewood, including within protected areas.
Three of four known sites for this species are within Forest Reserves: Mazumbai Forest Reserve; Ambangula Forest Reserve; and Shume-Mugambo Forest Reserve. However, all of these protected areas are subject to threats, such as smallholder agriculture and, logging, and firewood extraction.
It is important that habitat is conserved effectively for this highly unusual species. Despite occurring in three protected areas, it seem this species is not receiving sufficient protection against habitat destruction and fragmentation. Improved management of these Forest Reserves is a vital first step in the conservation of the Mazumbai warty frog. This should include working with local communities to find more sustainable and ecologically sensitive ways of harvesting wood and farming in the area. It would probably be beneficial to the Mazumbai warty frog to increase habitat continuity within its range by connecting some of the forest fragments where it is found. This would increase the ability of remaining individuals to disperse and move their genes between potentially isolated populations.