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Warts and All
By Jeanne Tarrant, Programme Manager of the EWT’s Threatened Amphibian Programme
Frogs are slippery in more ways than one. Frogs are creatures of the in-between, making use of both the
aquatic and terrestrial ecosystems. So too, is their place in human culture and folklore, with some
societies revering them and others being reviled by them. Their biphasic life-cycle has long been of
fascination to children, philosophers and scientists alike, and although well known by most people, is
still not fully understood.
Amphibians are the largest animals to undergo such dramatic metamorphosis, transforming from an
entirely aquatic to a terrestrial existence in the process. Tadpoles, also known as pollywogs in the US
and UK, are the most vulnerable life-stage of the frog’s existence. Small, soft and slow-moving they are
largely defenceless against predation and desiccation. In response, frogs have evolved a range of
mechanisms to improve the survival chances of their offspring. Many, in particular the toads, make use
of the “safety in numbers” principle by producing many 1000s of eggs. Other species have developed
elaborate modes of parental care: our own Giant Bullfrog male ensures that his juveniles stay connected
to water by excavating channels to the main water-body. Other species physically carry their eggs or
tadpoles to water or on their bodies until metamorphosis has taken place. For example, males of the
Chilean Darwin Frog keep eggs in
their vocal sacs for up to 70 days.
Some species stay close to their
young to protect them in various
ways. The female of the
Endangered Kloof Frog from
KwaZulu-Natal remains close to her
egg clutches, which are deposited
on
surfaces
above
water,
periodically urinating on them to
keep them moist.
The final phase of metamorphosis
is the most rapid, and the most
transformative. With the tadpole
swapping its vegetarian diet of
algae to an insectivorous diet it
requires a complete change of
filtering mouthparts to predatory
jaws. Front legs develop from the
pouch that previously contained
the mouthparts. The skin thickens
and develops glands to keep the
frog moist on land. The digestive
tract, lungs and nerves all undergo
dramatic changes and the eyes and
eyelids develop massively to
facilitate detecting moving prey.
This process has kept us intrigued for millennia, and is why frogs form a significant part of the cultural
history of many of societies. From the brothers’ Grimm “Frog King” to more recently, “Kermit the Frog”,
these often misunderstood animals have played an important role not only in scientific discovery and
natural history, but philosophy and folklore.
Even Carl Linnaues, often touted as the father of modern biology, and responsible for establishing the
binomial naming system still used for describing species today, had this to say about amphibians: “Most
amphibia are abhorrent because of their cold body, pale colour, cartilaginous skeleton, filthy skin, fierce
aspect, calculating eye, offensive smell, harsh voice, squalid habitation, and terrible venom; and so their
Creator has not exerted his powers to create them.”
The first vertebrates to step onto land approximately 315 million years ago, these creatures represent
an essential evolutionary link in biological history. In terms of human culture their image ranges from
harbinger of evil, to symbols of mythology, to food-source, to biology lesson. Unfortunately, many of
these beliefs place frogs in a negative light. Here in South Africa, many cultures hold ingrained fears and
superstitions about frogs. In a small survey conducted by the Woman’s Leadership and Training
Programme involving 120 Zulu people in KwaZulu-Natal found that frogs are the second most feared
animal (90%, after snakes, 98%), and that they are often purposefully killed. Often salt is used, which has
a devastating drying effect on the very sensitive skin of frogs. Overcoming such beliefs and practices is
thus crucial for improving the effectiveness of amphibian conservation efforts in South Africa.
The EWT’s Threatened Amphibian Programme is currently conducting a survey of the South African
publics’ attitudes to frogs to better understand these beliefs and develop educational and awareness
campaigns accordingly. Please complete the online survey here:
https://docs.google.com/forms/d/1SnUxjC31vsdudy4fxZTcwgqCBRDtqxAHPYQ5C39fhZw/viewform
We’d love to hear from you if you know of any interesting beliefs or stories about frogs. Please contact
[email protected]