Do different ecomorphs use different perches?

Do different ecomorphs use different perches?

by Alex Negro Science

South African scientists have investigated whether the physique of a dwarf chameleon affects the branches it prefers to use. In South Africa, three different ectomorphs, or body types, are known among dwarf chameleons of the genus Bradypodion: First, there is the forest ecomorph. This ecomorph is found in closed canopy forests, is large with a long tail, but relatively gracile. Typical for the forest ecomorph are bright colours and conspicuous gular and and casque ornamentations. The second ecomorph is the ‘small brown chameleon’, which occurs in open habitats such as heathland, grass savannah or fynbos. As the name suggests, this type of chameleon is small, inconspicuous brown or greenish in colour and has reduced gular and casque ornamentation. The third ecomorph is the bushland ecomorph: chameleons in bushland or thickets that are large but generally rather heavy-bodied and short-tailed, rather inconspicuous in colour, but with conspicuous gular and casque ornamentation.

The scientists measured the diameter and angle of the branches used by different Bradypodion species. The following species were among the test subjects: B. barabtulum, B. baviaanense, B. caffrum, B. damaranum, B. ketanicum, B. melanocephalum, B. occidentale, B. pumilum, B. setaroi, B. taeniabronchum, B. thamnobates, B. transvaalense and B. ventrale, as well as the three candidate species ‘emerald’, “groendal” and ‘karkloof’. Chameleons from 38 different populations across South Africa were measured at night and sorted into one of the three body types mentioned above. In addition, branch diameters and angles were measured every 10 metres along randomly selected 100-metre-long transects within a radius of one metre.

The data was then statistically evaluated. Between 2007 and 2024, a total of 1,755 adult Bradypodion and their branches were measured. The forest ecomorph chameleons had access to a much greater variety of suitable branches in terms of diameter and angle than in the other two habitats. The chameleons did not show a preference for certain branches in the forest, but rather ‘used what was available’. The habitat of the ‘small brown chameleons’, on the other hand, had significantly more vertical, thinner branches than the forest, but these had a similar angle. The density of branches was highest in this habitat. However, the ‘small brown chameleons’ chose vertical and usually thicker branches significantly less often than would have been available in their habitat. In the shrubland, the scientists found more vertical and thinner branches than in the forest, and in terms of number, the branches did not differ from the open habitat such as fynbos, but differed in branch diameter. The shrubland ecomorph was larger than those ecomorphs of the other two habitats. It was noticeable that the female shrubland chameleons preferred to use thicker branches and also preferred fewer vertical branches than were available.

The study shows that different ectomorphs of dwarf chameleons in South Africa do indeed occupy different habitat structures.

Comparing perch availability and perch use between African dwarf chameleon (Bradypodion) ecomorphs
Jody M. Barends, Melissa A. Petford, Krystal A. Tolley
Current Zoology 71(5), 2025: 633-644
DOI: 10.1093/cz/zoae076
Free download of the article

Graphic: The three different ecomorphs, from the above-mentioned publication

Cape dwarf chameleons are ambush predators

Cape dwarf chameleons are ambush predators

by Alex Negro Beobachtungen Science

For a long time, only two types of foraging behaviour were distinguished: active foragers and sit-and-wait or ambush foragers. Many years ago, two publications classified chameleons as ‘cruise foragers’, i.e. hunters that move slowly through the bushes, stop to feed and then move on. A study from South Africa is now investigating whether this is true and whether other factors contribute to movement. In order to evaluate the mode of foraging, one would actually have to ‘factor out’ movement for regulating body temperature, evading predators or opponents, searching for females or mate guarding.

To this end, 38 tagged (12 of them radio-tagged) Bradypodion pumilum were tracked over 10 days in April and 10 days in February. The chameleons live in Brümmer Park in Stellenbosch in the Western Cape province. They were divided into 17 male, 19 female and 2 indeterminate Bradypodion pumilum. The animals were located every evening and every morning on the specified days using telemetry and the naked eye. Each chameleon was observed for 60 to 180 minutes at a time, with two to four observers using binoculars from a distance of 5 to 10 metres from the chameleon being observed. The researchers recorded movements and stationary behaviour and assigned the corresponding motivation to each movement, noting food intake and number of shots.

A total of 171 hours of observation time was accumulated. Bradypodion pumilum spent most of the day (over 75%) stationary on their branches in Brümmer Park. In the morning, over 80% of them were sitting around, with almost half of this time spent sunbathing, presumably to warm up, and the other half spent stationary in shady vegetation. During the observation period, 26 Bradypodion pumilum fed a total of 110 times. They ate significantly more often (over 80%) when they were not moving. A strong factor for movement was interaction with conspecifics – during the observations, one male was even chased away by a female, causing it to fall from the tree.

The authors conclude from their study that Bradypodion pumilum is more likely to be a ambush hunter.

A multi-index approach to assessing foraging mode: a case study using chameleons
Wade K. Stanton-Jones, Krystal A. Tolley, Jody M. Barends, Graham J. Alexander
Current Zoology, 2025, zoaf065
DOI: 10.1093/cz/zoaf065
Free article download

Photo: Bradypodion pumilum tagged with a transmitter from the study mentioned above

Comparisons between dwarf chameleons in South Africa

Comparisons between dwarf chameleons in South Africa

by Alex Negro Science

South African scientists have recently been investigating whether three closely related Bradypodion lineages in the Eastern Cape Province of South Africa have evolved differently due to their different habitats or whether other causes are responsible.

The scientists are studying the two species Bradypodion ventrale from the Nama Karoo and Bradypodion taeniabronchium from the Elandsberg and Tsitsikamma Mountains and the fynbos of Thyspunt and Honeyville, as well as a population of dwarf chameleons from the fynbos of the Groot Winterhoek Mountains that has not yet been described as a separate species. The latter are often referred to as Bradypodion sp. ‘groendal’ because they occur in the Groendal Nature Reserve, among other places.

At night, chameleons were searched for using flashlights and the naked eye. Adult chameleons with a body length (SVL) of more than 36 mm were taken away overnight to be released back at the site where they were found the next day. All animals were measured accurately. Tissue samples were taken from the tip of the tail. In addition, the thickness and height of the branches on which the chameleons were found were measured. Further branch thicknesses were recorded along three 100 m long transects in each population. The data collected was statistically evaluated and the tissue samples were genetically examined.

A total of 232 chameleons were sampled for the study. Bradypodion taeniabronchium had significantly smaller head features than the other two species, but larger hands and feet. Bradypodion ventrale was larger overall than the others, but had longer limbs. Bradypodion taeniabronchium used the widest branches (average diameter 2.83 mm), but also the lowest (average height 82 cm above the ground). Bradypodion ventrale, on the other hand, used the thinnest branches (average diameter 1.52 mm), but the highest (average just under 93 cm above the ground).

The researchers found that all three populations of dwarf chameleons showed increased external similarity (convergence) when they occurred in the same habitats and less similarity (divergence) when they occurred in different habitats. The dwarf chameleons preferred certain branch thicknesses depending on their population, even though other branches were also available in their habitat. Finally, the authors point out that all the evidence available so far suggests that the as yet undescribed dwarf chameleons of the Groendal Nature Reserve represent a separate species.

Ecological factors promote convergent evolution and ecological speciation in dwarf chameleons (Bradypodion)
Krystal A. Tolley, Devon C. Main, Keith M. Dube, Bettine Jansen van Vuuren, Jessica M. da Silva
Zoosystematics and Evolution 101(3) 2025: 1227-1247
DOI: 10.3897/zse.101.151926

Photo: Bradypodion ventrale, from the publication cited

UV fluorescence in dwarf chameleons

UV fluorescence in dwarf chameleons

by Alex Negro Science

Chameleons have window-like, translucent scales over certain bony processes, especially on the head. If the bone is illuminated with UV light at these points, the areas light up. It has previously been assumed that this UV fluorescence or the fluorescent tubercles are used for intra-species communication. South African scientists have now investigated this further in dwarf chameleons.

Five Bradypodion species in different habitats (fynbos, forest, bushland) were studied.

If the fluorescent tubercles are used for communication between males and females during reproduction, one would have to assume that their number differs greatly between males and females. Chameleons that live in a dense forest should also have more of them than animals in open terrain that is easy for predators to see.

The result of the study is quite astonishing: the larger sex of each of the different dwarf chameleon species had the higher number of fluorescent tubercles. Bradypodion of the same size, on the other hand, always had approximately the same number of fluorescent tubercles on their heads. The different habitats did not appear to have any influence on the number of fluorescent tubercles. There was also no difference between habitats heavily influenced by humans, such as gardens, and near-natural, unspoilt landscapes.

The authors conclude that the fluorescent bone tubercles in South African dwarf chameleons are probably not used for communication. It remains to be seen whether this is also the case in other chameleon species.

Body size, not habitat or sex, best explains the extent of ultraviolet fluorescence in African dwarf chameleons (Bradypodion)
Jody M. Barends, Wade K. Stanton-Jones, Graham J. Alexander, Krystal A. Tolley
Journal of Zoology
DOI: 10.1111/jzo.70032

The microbiome in the gut of South African dwarf chameleons

The microbiome in the gut of South African dwarf chameleons

by Alex Negro Science

The term microbiome has been on everyone’s lips for some years now. In the intestine, this refers to the entirety of all microorganisms, especially bacteria, that colonise the mucous membrane. Now a group of researchers in South Africa has for the first time studied the gut microbiome in chameleons and how it changes in different habitats.

Three species of dwarf chameleons were searched for at night in the province of KwaZulu Natal with the help of torches: Bradypodion melanocephalum, Bradypodion thamnobates and Bradypodion setaroi. All animals were kept in containers for 24 hours and then released at the site. For each species, 10 buccal swabs and 10 faecal samples were collected in a natural and an urban habitat, resulting in a total of 120 samples. In the laboratory, DNA was extracted from the samples, amplified by PCR and then sequenced. Phylogenetic trees were created and statistical comparisons were made between the samples.

The samples were also analysed for zoonotic pathogens such as salmonella. However, only Campylobacter, Escherichia and Serratia were detected in human pathogens in the faeces. The authors conclude that the zoonotic potential of the microbiome of dwarf chameleons is very low.

In total, almost 350 different bacterial species were detected in the microbiome of the dwarf chameleons, which corresponds to other reptiles such as anoles and turtles. Proteobacteria, Firmicutes and Bacteroidota were most abundant in all samples. Overall, the microbiome was very similar in both buccal swab and faecal samples with only a few exceptions and slightly different depending on the species. The differences in the microbiome between natural and urban habitats were much smaller than expected. The microbiome of the buccal swab of Bradypodion melanocephalum living in urban environments showed more Caulobacteraceae and less Enterococcaceae than that in natural habitats, and Desulfovibrionaceae were more common in the faeces of urban animals. The microbiome of Bradypodion thamnobates showed more Ruminococcaceae and Akkermanisaceae in the faecal samples of urban chameleons. A striking feature of dwarf chameleons is the difference between the microbiota in the mouth and rectum, which has not yet been observed in other vertebrates. It remains to be seen whether chameleons in the animal kingdom have a specialized microbiome that could explain these differences.

Anthropogenic reverberations on the gut microbiome of dwarf chameleons (Bradypodion)
Matthew G. Adair​, Krystal A. Tolley, Bettine Jansen van Vuuren, Jessica Marie da Silva
PeerJ 13, 2025
DOI: 10.7717/peerj.18811

Photo: Bradypodion melanocephalum, photographed by Marius Burger

Utilisation of flap-necked chameleons at urban markets in South Africa

Utilisation of flap-necked chameleons at urban markets in South Africa

by Alex Negro Science

Scientists from the African Amphibian Conservation Research Group have analysed the existing literature on the subject. Fortunate M. Phaka also visited six municipal markets in Durban, Johannesburg, Petermaritzburg, Polokwane and Pretoria. At the markets, he searched for amphibians and reptiles sold for medicinal purposes and the names given to them by the vendors. He was able to interview 11 traditional health practitioners in Limpopo, Gauteng and KwaZulu-Natal in detail, from nine of whom he was allowed to take samples of the amphibians and reptiles sold for species identification.

In total, 33 species of reptiles and one species of amphibian used for traditional medicine were identified. Nine of these were found and identified on site during the market visits. The traditional healers interviewed stated that they had either hunted the animal parts themselves, bought them from hunters or taken them from roadkill. Fat and internal organs are removed, the carcasses are rubbed with ash or salt and dried in the sun. Usually, the healers’ customers do not buy complete carcasses, but only small parts of the reptiles on offer. Of the 111 animal samples taken, sufficient DNA to identify the species was obtained from 90 of them. 23% of the samples tested were incorrectly named by the healers.

Chamaeleo dilepis was among the reptile species utilised. No complete chameleon could be found at the markets visited. At the Warwick Muthi Market in KwaZulu-Natal, however, several reptile parts were sampled which, according to DNA comparisons, came from lobed chameleons. Chameleons in general were not identified to species level by the healers. The IsiZulu word unwabu stands for any chameleon.

Barcoding and traditional health practitioner perspectives are informative to monitor and conserve frogs and reptiles traded for traditional medicine in urban South Africa
Fortunate M. Phaka, Edward C. Netherlands, Maarten Van Steenberge, Erik Verheyen, Gontran Sonet, Jean Hugé, Louis H. du Preez, Maarten P.M. Vanhove
Molecular Ecology Resources Vol 25(2), 2025
DOI: 10.1111/1755-0998.13873

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