Dwarf chameleons in South Africa larger in urban environments than in the wild

Dwarf chameleons in South Africa larger in urban environments than in the wild

by Alex Negro Science

Dwarf chameleons of the genus Bradypodion from South Africa have long been known to adapt very well to urban habitats. Two scientists from Cape Town and Johannesburg have now investigated how different populations differ in body size, body weight and body condition score within urban and natural environments.

A total of 1107 individuals of five different dwarf chameleon species were studied over a period of four years. Bradypodion damaranum in George (Western Cape), Bradypodion melanocephalum in Durban (KwaZulu-Natal), Bradypodion setaroi in St Lucia (KwaZulu-Natal), Bradypodion thamnobates in Howick (KwaZulu-Natal) and Bradypodion ventrale in Jeffrey’s Bay (Eastern Cape) were each searched at night at three to eight locations. Forest fragments, grass savannahs or coastal bushland less than 15 km from the centre of the nearest town were classified as ‘natural sites’. All sites located within a city and consisting of both introduced and native flora regularly cut back by humans (gardens, public parks and green spaces, roadsides) were categorised as ‘urban’. The dwarf chameleons found were measured, weighed, sexed and marked with a felt-tip pen to avoid duplicate measurements on the same animals. Obviously pregnant females were not measured.

Statistical analyses and comparisons revealed that the chameleons at natural sites were always smaller and lighter on average than the populations of the same species at urban sites. Significantly larger and heavier in the city were both sexes in Bradypodion damaranum, the males in Bradypodion melanocephalum, ventrale and setaroi and the females in Bradypodion thamnobates. The body condition score was higher in urban areas for both sexes of Bradypodion damaranum and setaroi and males of Bradypodion melanocephalum than for the chameleons in natural habitats. In Bradypodion ventrale and thamnobates, there were no differences in body condition score between the different populations.

Research into exactly how these exciting differences come about is still pending.

Big cities, big bodies: urbanisation correlates with large body sizes and enhanced body condition in African dwarf chameleons (Genus: Bradypodion)
Jody M. Barends, Krystal A. Tolley
African Zoology 2024, 59(3)
DOI: 10.1080/15627020.2024.2402256

Photo: Bradypodion melanocephalum, photographed by suncana, licence Creative Commons Attribution 4.0 International

What influences colour patterns in chameleons

What influences colour patterns in chameleons

by Alex Negro Science

Chameleons are known for their ability to change colour. International scientists have now investigated what exactly influences different colour patterns in different populations. They want to know to what extent the habitat itself, the distance to other populations or social interactions influence the colour change.

The test subjects were European chameleons (Chamaeleo chamaeleon) caught in La Herradura and Sanlúcar in Spain. The two regions are around 230 kilometres apart. Other Chamaeleo chameleon were collected in the north-western Negev and on the Carmel coast in Israel (around 180 km apart). On the other hand, flap-necked chameleons (Chamaeleo dilepis) were captured in Simbithi, Zulu Falls and Maduma Boma in South Africa. The three locations are between 100 and 550 kilometres apart.

Each chameleon was subjected to two experiments. In the first, the scientists let the chameleon walk two metres on a horizontal stick, which was placed in the sun about one metre above the ground. In the second experiment, a second chameleon of the same species was placed on the same stick 50 cm away from the first. The colour patterns shown by the animal during the experiments and its behaviour were recorded for 20 minutes. The data was then analysed using computer programs. Blood was taken from a cut claw of all chameleons and genetically analysed. The habitats and soil conditions were also analysed in various ways and statistically evaluated. The captured animals were kept in ventilated plastic cages for a maximum of 12 hours and released after the analyses. Unfortunately, the study does not mention how many chameleons were caught and released in total.

As expected, it turned out that the individual populations of both the European and the flap-necked chameleon differed genetically from each other. The populations of Chamaeleo dilepis had significantly different haplotypes.

In the flap-necked chameleon, the females were significantly larger than the males in two locations, but not in Simbithi. The scientists also found that the colour patterns of the three populations studied could be clearly distinguished from each other. They concluded from the results that the colour patterns in Chamaeleo dilepis are primarily dependent on genetic isolation. The habitat itself and the size of the chameleons did not influence the colour patterns.

In the European chameleon, however, the situation was different: Body size and genetic distance to other populations predicted colour patterns in males very well. However, the colour patterns were independent of the location where the animals were found. Soil or vegetation colours only had a minor influence on the colour of females.

Genetic and behavioural factors affecting interpopulation colour pattern variation in two congeneric chameleon species
Tammy Keren-Rotem, Devon C. Main, Adi Barocas, David Donaire-Barroso, Michal Haddas-Sasson, Carles Vila, Tal Shaharabany, Lior Wolf, Krystal A. Tolley, Eli Geffen
Royal Society Open Science 11: 231554
DOI:  0.1098/rsos.231554

Knysna dwarf chameleons: city vs. forest habitat

Knysna dwarf chameleons: city vs. forest habitat

by Alex Negro Science

How do chameleons change when their natural habitat has to make way for human settlements? International scientists recently got to the bottom of this question. They hypothesised that a chameleon living in a suburban area must differ from its forest-dwelling conspecifics in terms of injury frequency, external characteristics and bite force as an expression of changed living conditions.

Between 2020 and 2022, 276 Knysna dwarf chameleons (Bradypodion damaranum) were studied in South Africa. The locations chosen were George and Knysna, two towns located around 60 kilometres apart on the south coast of South Africa. George was founded in 1811 and now has over 220,000 inhabitants, while Knysna was founded in 1825 and currently has just under 76,000 inhabitants, although they live in much less space and are therefore much more densely populated. In both cities, Bradypodion damaranum were caught in urban environments (private gardens, public parks, roadsides), examined and then released. Chameleons were also studied 10 to 12 kilometres away in their natural habitat (temperate forest). The adult chameleons were measured and photographed. The data was analysed and compared using various methods. Wounds, scars and bone fractures visible to the naked eye were counted as injuries. To measure bite force, the animals were each encouraged to bite five times on a special piezoelectric measuring device.

The analysis showed that the dwarf chameleons in urban environments had significantly lower casques and shorter gulars. The males from the city, however, had larger and wider heads. The female dwarf chameleons from the forest had significantly larger casque spurs. The males in the city had significantly more injuries (88.1%) compared to the males in the forest (72.5%). In the city, the dwarf chameleons also bit harder than in the forest when casque height and parietal crest were included in the calculations. However, when snout-vent length was included instead, there was no difference in bite force.

Differences between urban and natural populations of dwarf chameleons (Bradypodion damaranum): a case of urban warfare?
Melissa A. Petford, Anthony Herrel, Graham J. Alexander, Krystal A. Tolley
Urban Ecosystems 2023
DOI: 0.1007/s11252-023-01474-1

Presentation in Mönchengladbach about South Africa

Presentation in Mönchengladbach about South Africa

by Alex Negro Reiseberichte Live lectures

On Friday, 3 November 2023, Reinhard Münzer will give a lecture on a trip to South Africa that is not just about herpetology. The country, which is 3.4 times the size of Germany and has a diverse natural environment, offers the best conditions for exciting and varied discoveries. The lecture will not only show reptiles, but of course also the Big Five.

Reinhard Münzer Travel impressions South Africa
DGHT regional group Mönchengladbach/Krefeld
Vereinsheim SC 08 Schiefbahn
Siedlerallee 27
47877 Willich-Schiefbahn
Meeting from 7.30 pm, presentation starts at 8.00 pm

Picture: Reinhard Münzer

The microbiome of dwarf chameleons

The microbiome of dwarf chameleons

by Alex Negro Tiermedizin Science

The term microbiome has been very popular for some years now. In humans and animals, it refers to the totality of all microorganisms that colonise a living being. Most of them colonise the gastrointestinal tract. In the case of chameleons, there is only very limited literature on this topic. A master’s thesis from South Africa now deals with the bacterial composition of the microbiome in South African dwarf chameleons of the genus Bradypodion.

60 cheek swabs were collected from wild chameleons in KwaZulu-Natal. Of these, 20 were cheek swabs from Bradypodion melanocephalum, 20 from Bradypodion thamnobates and 20 from Bradypodion setaroi. After sampling, the same 60 animals were transported in cloth bags to the research base, where the animals were kept in 3.3 l boxes for 24 hours to obtain faecal samples. Since not all of the original 60 chameleons defecated, faeces were collected from additional chameleons.

The samples were all genetically tested. 40.43% of the samples contained Firmicutes, a similarly large proportion of the samples contained Proteobacteria with 36.86%. Bacteroidota followed with some distance, which could be detected in just under 16% of the samples. Verrucomicrobiota, Fusobacteriota, Actinobateriota, Spirochetes, Desulfobacteroa, Cyanobacteria, Thermoplamatota, Deferribacterota, Synergistota, Campylobacterota, Deinococcota, Halobacterota, Euryarchaeota, Elusimicrobiota and Myxococcota were found in significantly smaller numbers (up to 2%).

The microbiome of dwarf chameleons of the species Bradypodion melanocephalum, Bradypodion thamnobates and Bradypodion setaroi is similar to that of other reptiles. It consists mainly of proteobacteria and firmicutes, which may contribute to digestion. One particular bacterial species also suggests that the diet of the studied dwarf chameleons may include beetles of the genus Dendrophagus. The microbiome of all three dwarf chameleon species was very similar in the cheek swabs – this is called phylosymbiosis – while there were differences in composition between the species in the faeces. In all three dwarf chameleon species, significantly more different bacteria were found in the faeces than in the cheek swabs. A comparison between males and females did not reveal any significant differences in the microbiome of all three chameleon species. The author assumes that the bacterial species depend on the different habitats of the respective species. It is still unclear to what extent the microbiome is related to bacteria that a chameleon may ingest with feeding insects or from the soil of its environment. A detailed list of the bacterial species found can be found in the appendix of the publication.

The Hitchhiker’s Guide to dwarf chameleons (Bradypodion): The composition and function of the microbiome
Matthew G. Adair
Master of Science dissertation at the university of Johannesburg, 2023
DOI: not available

Chamaeleo dilepis in traditional south african medicine

Chamaeleo dilepis in traditional south african medicine

by Alex Negro Science

Researchers from North-West University in South Africa have investigated which reptiles are used by traditional healers and how much they actually know about the species used. They visited six medical shops and markets (muthi shops/markets) in Polokwane, Pretoria, Johannesburg, Pietermaritzburg and Durban. Twelve traditional healers were also visited, two each in Limpopo and Gautend and seven in KwaZulu-Natal. Healers who agreed to be interviewed were asked about the species and origin of reptiles they use. Samples were taken for genetic testing from 111 carcasses and tissue remains (some only bones with meat remains) offered for sale.

Of the 34 reptile species known so far from the literature to have been traditionally used in South African medicine, nine could be confirmed. The healers reported that they partly hunted the reptiles themselves and partly bought them from specialised hunters. To the astonishment of the researchers, reptiles killed in road traffic (“roadkills”) were also used by healers. For sale and use, the reptiles were preserved. Fat and internal organs were removed manually. The fat was kept in bottles as it could be sold individually. The organs were not used further. The carcasses of the reptiles were then rubbed with ash and salt and dried in the sun. All healers agreed that whole carcasses were rarely sold – usually customers only wanted to purchase certain body parts, as only these were known for their effects.

The flap-necked chameleon was already known to be an occasional species at traditional South African healer markets. Several Chamaeleo dilepis were also identified in this study, but they were only marketed with an umbrella term in isiZulu. Unwabu refers to any species of chameleon, not specifically Chamaeleo dilepis. For other reptile species, some of the healers’ names matched the identified species down to the species level. However, there were also quite a few misidentified specimens where completely different reptiles were identified by the healers than turned out to be the case in the genetics.

Barcoding and traditional health practitioner perspectives are informative to monitor and conserve frogs and reptiles traded for traditional medicine in urban South Africa
Fortunate Phaka, Edward Netherlands, Maarten van Steenberge, Erik Verheyen, Gontran Sonet, Jean Hugé, Louis du Preez, Maarten Vanhove
Molecular Ecology Resources [Preprint], 2022
DOI: 10.22541/au.166487945.53921162/v1

Species diversification in chameleons

Species diversification in chameleons

by Alex Negro Science

From earlier studies, we know that the first chameleons evolved in the late Cretaceous, about 90 million years ago, on mainland of Africa. Around the border between the Cretaceous and Tertiary periods, about 65 million years ago, different species began to evolve. It is still unclear today which factors contributed to the diversity of species. Two researchers from Swansea University in Wales have now used various computational models of phylogenetics to investigate what might have influenced diversification (the splitting of chameleons into many different species).

First, they studied the diversification of chameleon species in Madagascar. In terms of evolutionary history, there are two points in time when chameleons apparently spread across the sea from mainland Africa to Madagascar. One is about 65 million years in the past, the other 45 million years. You could now think that the climatically extremely different habitats in Madagascar could have driven the evolution of the species very quickly after the spread across the sea. To the surprise of the researchers, however, no evidence of this was found. The species richness of chameleons on Madagascar must therefore come from the fact that chameleons spread there very early and thus simply had much more time to develop into different species than elsewhere.

Furthermore, the researchers investigated whether switching between two ecomorphs – from ground-dwelling stub-tailed chameleons to tree-dwelling chameleons with longer tails – had an impact on species diversity. Rather surprisingly, this did not seem to be the case. The evolution to tree-dwellers with longer tails occurred relatively early on one or two occasions. No evidence could be found that different ecomorphs accelerated diversification. Instead, speciation rates were found to slow down progressively over the last 60 million years. Only a very early dispersal event of the genus Bradypodion in South Africa around 10 million years ago was accompanied by a two- to fourfold diversification rate.

As a third focus of the study, the researchers examined the genus Bradypodion. During the climate change in the Miocene around 10 million years ago, South Africa changed a lot. Forests disappeared, leaving behind isolated forest habitats and, in between, savannahs, some of which are now so-called hot spots of biodiversity. Two of them, the Cape Floristic Region at the southwestern tip of South Africa and Maputuland-Pondoland-Albany on the east coast of South Africa, are home to a particularly large number of Bradypodion species. Each species is limited to a geographically very clearly defined area. The researchers, therefore, suspect that Bradypodion species have actually evolved faster under the influence of habitat change. It should be noted that the diversification rate of the genus Bradypodion is probably rather underestimated, as there are still many hidden species to be assumed.

Diversification dynamics of chameleons (Chamaeleonidae)
Stephen Giles, Kevin Arbuckle
Journal of Zoology, 2022
DOI: 10.1111/jzo.13019

Preferred perches in Bradypodion pumilum

Preferred perches in Bradypodion pumilum

by Alex Negro Science

It has long been known that most chameleon species move around on branches. However, research into how and which branches they prefer to use has so far been based mainly on nocturnal observations. At night, chameleons are easier to find in bushes and trees because they usually sleep on the ends of branches and are easy to spot with a torch. However, less is known about the use of perches during the chameleons’ active time, namely during the day. The herpetologist Kristal A. Tolley from the Kirstenbosch Research Centre in Cape Town, South Africa, has now conducted a study to find out which perch sizes Bradypodion pumilum prefers at night and during the day.

It is known from other tree-dwelling reptiles that they tend to seek out thinner perches at night, but use different perch sizes during the day. The result of the study was all the more surprising: the branches used by Bradypodion pumilum did not differ in diameter or variety during the day and night. An astonishingly high range of branches was used overall. The only correlation found was with body size, which seems logical in principle: The larger the chameleon, the thicker the perches used.


Is it like night and day? Nocturnal versus diurnal perch use by dwarf chameleons (Bradypodion pumilum)
Krystal A. Tolley
African Journal of Herpetology
DOI: 10.1080/21564574.2022.2098392

Hidden species within the genus Chamaeleo

Hidden species within the genus Chamaeleo

by Alex Negro Science

Thanks to genetic studies, the identification of species is much more precise today than it was a few decades ago. However, genetics always raises new questions. The genus Chamaeleo currently has 14 species. Scientists from South Africa have now investigated whether there might be other ‘hidden’ species of the genus Chamaeleo. At the same time, they investigated where the origin of the genus Chamaeleo might lie. For this purpose, the genetic material of all 14 species recognised so far was examined. Exciting results came to light: of the fourteen Chamaeleo species, thirteen were confirmed, but one was questioned. In addition, several new candidate species were identified.

The two different populations of Chamaeleo anchietae in western Angola and in south-eastern Congo and Tanzania probably represent two different species. If the animals from the Democratic Republic of Congo and Tanzania were true to be elevated to species status in the future, they would have to be named Chamaeleo vinckei according to taxonomy and a species description from 1950.

Chamaeleo gracilis seems to hide – which would not be surprising due to its wide distribution – at least three independent species. The “real” Chamaeleo gracilis would be found in Liberia, Sierra Leone and Guinea. The other two groups originate from the triangle of countries between Chad, Cameroon and the Central African Republic and from the border between Kenya and Tanzania. Unfortunately, only single specimens of Chamaeleo gracilis have been sampled, so no more far-reaching recommendation on the splitting of species can be made at this point.

The flap-necked chameleon (Chamaeleo dilepis), currently described as a single species, could contain a total of three species. One of the genetically distinct populations occurs in eastern Africa in Tanzania and Rwanda, while a second species is found in southern and eastern Africa, from South Africa through Botswana, Zambia, Namibia, Mozambique and Malawi to southern Tanzania. The third species would be distributed in west central Africa between Angola and the Congo. None of the candidate species matches the eight subspecies described so far purely on the basis of appearance. Therefore, a complete review of the previous subspecies, their status and the species status of the three newly emerged clades is necessary.

The results of the study on Chamaeleo necasi from Benin are also interesting. It turned out that the genetics identified the sampled animal as Chamaeleo gracilis. However, the specimen itself was not examined by the researchers. It could be a Chamaeleo gracilis misclassified by its appearance. In this case, the specimens used for the species description in 2007 would have to be viewed and sampled again in order to obtain more information about the actual species’ status.

In the course of the genetic investigations, the researchers found out that the origin of the genus Chamaeleo probably lies in South Africa. Chamaeleo namaquensis, the only terrestrial chameleon of the genus Chamaeleo, split off from the other Chamaeleo species as early as 40 million years ago in the Eocene. This makes the Namaqua chameleon from the Namib Desert and Damaraland the “oldest” chameleon of the genus Chamaeleo. Chamaeleo anchietae followed about 29 million years ago.

Out of southern Africa: origins and cryptic speciation in Chamaeleo, the most widespread chameleon genus
Devon C. Main, Bettine Jansen van Vuuren, Colin R. Tilbury & Krystal A. Tolley Conceptualisation
Molecular Phylogenetics and Evolution, Volume 175
DOI: 10.1016/j.ympev.2022.107578