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| November 2004 |
Feature |
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Under the charm of chameleonsEngela Duvenage, Stellenbosch University
Have you ever been introduced to a friend's new boyfriend who is an extremely aesthetically challenged guy, but whose looks (or lack thereof) you simply forget about after a while because you were so mesmerized by how in love the couple seemed? That's also the experience you get when listening to chameleon researcher Dr Krystal Tolley in her office at the University of Stellenbosch Botany and Zoology Department chatting away about her research topic of the past three years. Chameleons, to say the least, are ugly, yet adorable. "I used to work on marine mammals, which everyone finds cute and cuddly, but now, these dwarf chameleons, they are just…" Words seem to escape her as she tries to explain her enthrallment with these reptiles. Does the charm of a chameleon come from their amazing long tongues, their protruding eyes that can turn independently in all directions, their prehensile tail that they curl up behind them when at rest or their slow, calculated movements across a branch? Regardless of the reasons for the fascination with chameleons, she finds this group extremely interesting from a scientific point of view. The ultimate goal of her research aims to aid conservation planning of herpetofaunal (reptiles and frogs) biodiversity in the region. To do this, she conducts studies on the genetic variation found between various species of dwarf chameleons in order to understand better the evolutionary processes that have created species diversity and geographic distribution. The analyses are conducted at the University of Stellenbosch Evolutionary Genomics Laboratory.
This blonde American did her Masters degree on fish in the USA, followed by studies in Norway for her doctoral degree on harbour porpoises. She wanted to study seals in South Africa, but as life is full of surprises, she was invited to do further research at the University of Stellenbosch' Department of Botany and Zoology. "If anyone had told me a few years back that I would now be working on chameleons, I wouldn't have believed it." Now, as her work progresses, there are so many questions at hand about dwarf chameleons that her research could simply go on forever. After she has surveyed the Cape Fold mountains, stretching from the Cederberg to beyond Port Elizabeth, there's always the northern parts of South Africa, where different species of chameleons also occur.
There are fifteen recognised species of dwarf chameleons (Bradypodion) in South Africa, of which five are endemic to the Cape Fold Mountains. In addition, there appear also to be several other undescribed species present in these mountains. Unfortunately, the geographic distribution of many of these species remains largely unknown, and their taxonomy, distribution, and diversity is poorly understood. Most research work so far on chameleons in South Africa has focused on classifying the various species that are found. It is very difficult to tell the Bradypodion species apart. "On first glance, they all look quite the same - all small, greenish-brown, with rolling eyes," she sums it up. But on closer inspection, it appears that there can be a large amount of colour and scale variation, even within the same species. Luckily, with the help of genetic tests, it is now possible to make a better distinction between species, because each one has its own specific DNA code. This makes further work on the morphological differences between species possible. Thanks to her research and surveying, it has now been found that the Robertson's dwarf chameleon, once thought to be restricted to the Breede River area, is more widespread and is found from the Cederberg/Porterville-areas all the way to the Outeniqua and the Kammanassie mountains. In the Eastern Cape, things are even more hectic in terms of chameleons. A variety of different DNA lineages has been found, which could indicate more species. The University of Stellenbosch's Faculty of Science, with help from the National Research Foundation and the WWF-Table Mountain Fund, funds her Cape Fold Dwarf Chameleon Project. The project links up with the Cape Fold Montane Herp Project. This means that on field trips she buddies up with researchers from the University of Pretoria, University of the Western Cape, and Cape Nature Conservation who are part of the project, which aims to catalogue the species diversity, genetic diversity and conservation of reptiles and amphibians of the Cape Fold Mountains. One of Krystal's most valued possessions during field trips is her flashlight, because it is much easier to find chameleons at night. They are active by day, but at night, they can be found by torchlight as they sleep, clinging to a spindly branch. The moment something touches it, the chameleon drops to the ground in a reflex movement designed as a safety measure for avoiding nocturnal predators. With or without a flashlight, it is not easy to spot a chameleon. In addition, if you have to hike for three days to get to a preferred spot, attention spans tend to wane too. It takes skill to see one, while the density of the vegetation can also play a role. "You start to learn which types of plants they prefer to perch on, but it is not to say that you'll find any when you go looking for them," she says. Chameleons living in trees and forests are especially difficult to find. So far, hundreds of new sightings of chameleons in provincial nature reserves and private land in the Western and Eastern Cape have been recorded. In some areas, chameleons are reasonably well-sampled, while other areas have never been studied. Because they are so small and well-camouflaged, many a chameleon goes unnoticed. "Many times you visit a farmer who says he's never seen a chameleon on his land, and then when we start looking there are quite a lot of them around." "We have no idea of how many chameleons there are - do we just not see them because they are often so well camouflaged, or are their densities really low?" These and a whole list of other questions far longer than a chameleon's telescopic tongue, still need to be answered. While Dr Tolley is more interested in their DNA samples for her genetic study, all the observations are included in Cape Nature's fauna database to provide a picture of species distribution. More on chameleons:A chameleon, with its compressed body covered in small granular scales, is
the most easily recognised species of lizard. Its protruding eyes, which can
move independently, are especially characteristic. It has a telescopic tongue
that can be shot further than its body length to capture prey. Most chameleons live primarily in trees, bushes and on other plants, but at least one South African species is terrestrial. Fifteen species occur in South Africa. A few newly discovered species await description. Chameleons are only active by day. They primarily eat insects. More information: For more information, visit http://www.sun.ac.za/zoology/tolley/chameleon_project.htm Information from www.capenature.org.za/cederbergproject
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