FROGS are members of a diverse group of short-bodied, tailless amphibians. There are approximately 4800 recorded species worldwide. Frogs typically lay their eggs in water, the eggs hatching into aquatic larvae called tadpoles. Almost all frog species are carnivorous as adults, preying on worms, insects, slugs and snails. They themselves are an important source of food for many predators and are therefore part of the food web dynamics of many of the world’s ecosystems. More than one-third of frog species are considered threatened with extinction.
FROGS that you might just spot or hear in Fernkloof
The Arum Lily frog Hyperolius horstockii is found in the Western Cape and a small part of the Eastern Cape. The frogs grow to 40 mm in length and are pale cream to light-brown in colour. However they can change colour to perfectly match their surroundings. They hide their bright orange feet and legs under their bodies during the day. The frogs breed in wetlands, the males usually calling at night. The female lays a clutch of 10-30 eggs which are attached to the submerged roots and stems of plants. The frogs occasionally use Arum Lily (Zantedeschia aethiopica) flowers for shelter and as a place to catch prey. However they are not dependent on the plant and are not involved with its pollination.
The Cape River frog Amieta fuscigula is the frog you will most likely see as it watches you from the side of a pool. It is fairly large, up to 125mm in length and looks like a typical frog. It has long hind legs and feet, well adapted to leaping and swimming. The colour ranges from dark- through to light brown and also olive. As you walk along the edge of a dam and hear the plopping of frogs as they leap into the water it is most likely the Cape River frog. It dives deep to hide under water vegetation. It occurs in a wide range of habitats and needs fresh water for breeding.
The Cape Rain frog Breviceps gibbosus was the first species of frog from Southern Africa to be identified by Linnaeus in 1758. If a frog can be called cute, it has been described as the ‘cutest little frog ever’! Their toes are thick and unwebbed and when they walk they waddle. When alarmed they increase in size by swallowing air, hence the common name ‘Blaasop’. An adult can grow up to 45mm in length. It spends most of its life underground, emerging during rain or when mist is present. Thick muscular legs enable it to burrow for shelter. They inflate and float in water and will drown if they cannot reach ground quickly. The call is a harsh squawking at short intervals.
Clicking Stream frog Strongylopus grayii is a small species 25 to 50mm. The colour of the dorsal skin is usually shades of brown with darker blotches. The frogs may often have a vertebral line in a contrasting colour. Breeding takes place in almost any shallow vegetated water. In breeding season its voice is a musical click, a bit like the sound of a droplet of water dropping into a pond. When a large chorus is active the effect is like a loud continuous rattle. They can swim rapidly, but if they are unable to leave the water they will drown.
Fernkloof’s own Drewes’ Moss frog Arthroleptella drewesii was discovered in the Reserve in 1994 by Dr Abeda Dawood, Dr Denver Hendricks and Professor Alan Channing all from, at the time, the University of the Western Cape. This tiny cryptic frog, just exceeding 20mm in length, lives in leaf litter and mossy places around mountain seeps or along banks of vegetated streams. They are able to jump out of harm’s way in an instant! The male call is quite distinctive – a series of more or less evenly spaced clicks, 5 – 10 single or double clicks produced in .7 of a second.