Bufo garmani Meek, 1897
Eastern Olive Toad, Olive Toad, Garman’s Toad, Olyfskurwepadda (A)
Currently accepted name: Sclerophrys garmani (Meek, 1897)
Red listing status: Least Concern
Photo by Grundlingh Felicity, 2013. URL: FrogMAP: 1061
B. garmani has a wide distribution in the eastern savannas of Africa, ranging from Somalia in the north to South Africa in the south (Poynton 1964; Channing 1991). In the atlas region, the species occurs in northern KwaZulu-Natal and extends to the northwest through the lowveld of Swaziland, Mpumalanga and Limpopo provinces, and westward along the Limpopo River valley.
Some confusion exists as to the western limit of the distribution of B. garmani, as it is difficult to distinguish this species from the morphologically similar B. poweri (see B. poweri species account). While the advertisement call of B. garmani has a relatively slower pulse rate and shorter duration than that of B. poweri (Channing 1991), this can be determined only by sonagraphic analysis. The majority of the atlas distribution records for these two species were not based on tape recordings and therefore the distribution data for B. garmani and B. poweri have been combined and are presented here in a single map. More intensive distribution surveys based on recorded calls and molecular analysis are required to elucidate the distributions of these species. In other respects the atlas data are reliable.
This species inhabits various bushveld vegetation types in the Savanna Biome and seems to prefer well-wooded, low-lying areas with high daytime temperatures. During the day, individuals may be found under fallen logs, rocks and mats of vegetation, or beneath any object that provides shelter around houses. In northern Kruger National Park, specimens have been found in abandoned termitaria (H. Braack pers. obs.).
Breeding usually occurs in small, shallow, temporary water bodies, but occasionally the quiet backwaters of rivers and pools along small, slow-flowing streams are used (Lambiris 1989a). They also breed in artificial water bodies such as farm dams and ornamental ponds around homesteads. In the urban environment, B. garmani is less common than B. gutturalis.
Most breeding takes place during spring and summer, continuing into January and occasionally February. Breeding commences after the first substantial spring rains, or earlier if artificial water bodies such as garden ponds are available.
Males call from the edges of water bodies, often forming small choruses. They exhibit call-site fidelity, returning to the same site even when removed and released a considerable distance away (Pienaar et al. 1976). Amplexus is axillary, and displacement of amplexing males is frequent, with “knots” of several males and a single female forming at times (H. Braack pers. comm.). Eggs are laid in double strands containing up to 12 000–20 000 eggs (Channing 2001). The eggs hatch within 24 hours; metamorphosis takes place after 64 days (Du Preez 1996). Tadpoles assume a lighter or darker colouring to match the substrate (Channing 2001).
The eggs of B. garmani are eaten by the Serrated Hinged Terrapin Pelusios sinuatus, Müller’s Platanna Xenopus muelleri, and by their own tadpoles, while the adult frogs are taken by young crocodiles (Channing 2001). Other predators include various small carnivores, snakes and birds. Their prey includes beetles, termites, moths, insect larvae and other small invertebrates. After rain, when alate termites emerge, these toads congregate around the openings of termitaria where they gorge themselves on alates (Pienaar et al. 1976).
B. garmani is a common and widespread species and occurs in a number of national parks and provincial and private nature reserves. Much of its habitat is used for cattle and game ranching and is therefore not threatened. On the contrary, it is possible that the species has expanded its range as a result of the construction of artificial watering points for livestock.
Although the species is not under any immediate threat and is not a conservation priority, many of these toads are killed by motor vehicles as they cross roads at night during the breeding season (Pienaar et al. 1976). Many also suffer violent deaths at the hands of intolerant humans, irritated by their mating calls – a great pity as these vigorous calls are a quintessential feature of African bushveld nights. The fate of these and other frogs highlights the need for public education in the fascinating biology and ecological significance of frogs.
Current distribution map
Undated records; pre-1996; 1996 to 2002; 2003 to present
FrogMAP. 2018. Bufo garmani Meek, 1897. Animal Demography Unit. Accessed from http://frogmap.adu.org.za/?sp=320; on 2018-08-22 09:08:14.
Minter L.R., Burger M., Harrison J.A., Braack H.H., Bishop P.J. & Kloepfer D. (eds). 2004. Atlas and Red Data book of the frogs of South Africa, Lesotho and Swaziland. SI/MAB Series no. 9. Smithsonian Institution, Washington, D.C. Published by the Smithsonian Institution and the Avian Demography Unit (now Animal Demography Unit).