The population of Furcifer labordi in Andranomena (Madagascar)

The population of Furcifer labordi in Andranomena (Madagascar)

by Alex Laube Science

After we already discussed a preprint on the habitat of the Labordes chameleon (Furcifer labordi) in Andranomena, Madagascar, last year, the final publication now followed after a long peer review. In fact, the focus of the paper was reconsidered and adapted.

Labordes chameleon (Furcifer labordi) has been known for several years as the world’s shortest-lived chameleon. Five scientists from Madagascar have recently investigated which factors influence the distribution and population size of the species. The study was carried out in the Andranomena Special Reserve, which is located around 30 kilometres north of the coastal town of Morondava in western Madagascar. The special reserve has various habitats used by the chameleons, such as intact dry forest with parts near and far from water as well as regrowing / heavily modified forest.

Distance sampling was used to estimate the population density of Furcifer labordi. For this purpose, each part of the forest was divided into three 50 metre transects over a width of 150 metres. At night, the chameleons were then searched for with a torch, their location measured and the animals themselves marked in colour with nail varnish. Faecal samples were collected and analysed. The following day, a 5 x 5 metre plot was marked around each site and at least 5 metres away along the transect line. In all plots, the degree of canopy cover in per cent, the thickness of the foliage layer on the ground and ground-covering plants in centimetres, the number of shrubs up to 1 m, the number of trees over 1 m and the number of felled and burnt trees were counted. Five days after the first count, chameleons were again searched for and counted at night. In addition, insects were counted and identified using light traps. Along a 1400 metre transect, observations of six species of birds of prey and four species of snakes were also counted as examples. Unfortunately, the exact species are no longer named.

Statistical analyses showed that more Furcifer labordi were found in forest sections where the canopy was denser, the foliage layer on the ground was thicker and there were more trees overall. In the parts of the forest where no chameleons were found at all, significantly more felled trees were counted. The predators observed or their presence did not appear to have any influence on the population density of the chameleons. Surprisingly, the suspected feeders present, mostly insects, also showed no effect on the distribution of the chameleon population. The height of the branches on which Furcifer labordi were found varied greatly over the observation period. However, no correlation was found between age and sex. Preferences in the choice of plants used could not be observed in the chameleons. Furthermore, the different age groups showed no clear preference in their choice of microhabitat.

The authors conclude that the declining population size is primarily due to habitat loss. Habitat loss in Andanomena is almost exclusively of human origin (deforestation for agriculture and cattle grazing, slash-and-burn).

Analyses spatiales de population de Furcifer labordi (Grandidier, 1972) dans la Réserve Spéciale d’Andranomena, Morondava-Madagascar
Philibertin Honoré Djadagna Ahy Nirindrainiarivony, Achille Philippe Raselimanana, Lily-Arison René de Roland, Willy Nathoo Veriza, Daudet Andriafidison
European Scientific Journal 20 (15), 2024,
DOI: 10.19044/esj.2024.v20n15p48
Informations about the preprint

Chameleons as prey of Compsophis infralineatus

Chameleons as prey of Compsophis infralineatus

by Alex Laube Beobachtungen Science

Some interesting observations were recently made in central eastern Madagascar. Two snakes of the species Compsophis infralineatus were observed trying to devour chameleons as prey. Overall, not much is known about these snakes, but they were long thought to be primarily frog and egg eaters. An observation from 2018 already reports an attempt by another Compsophis species to eat a chameleon, which was regurgitated.

The current observations were made in the private rainforest of Vallombre Natiora near Mandraka. During night walks, an adult Compsophis infralineatus was discovered eating an adult Calumma gastrotaenia. The entire process of consumption was not observed, the snake had disappeared on return to the site, as had the chameleon. The authors assume that the chameleon was successfully devoured. On the same night, another snake of the same species was seen attempting to eat an adult Calumma crypticum. The chameleon was still alive and tried to free itself from the snake’s coils, but seemed unsuccessful first. Later, the same snake was seen again, hanging with its mouth in the back of the chameleon, which was apparently still alive but no with the snake wrapped around it. In the photo, it appears that the chameleon is still alive.

Predation on the chameleons Calummy crypticum Raxworthy and Nussbaum, 2006 and C. gastrotaenia (Boulenger, 1888) by the snake Compsophis infralineatus (Günther 1882) near Mandaka, Madagascar
Devin A. Edmonds and Samina S. Sam-Edmonds
Herpetology Notes (17), 2024: pp. 327-328
DOI:  not available

Picture: from the above-mentioned publication, CC BY-NC-ND 4.0

Longer in the egg than alive

Longer in the egg than alive

by Alex Laube Internationaler Chamäleontag

A chameleon that’s been in the egg longer than it’s been alive? It does exist! Of course, not every Labord’s chameleon (Furcifer labordi) is like this. But this is probably the shortest-lived chameleon in the world. They live in western Madagascar, where it is very hot and dry most of the year. During the short, intense rainy season, the chameleons hatch, grow to adulthood at record speed, mate immediately and lay eggs quickly before most of them die in the same season. The average Labord’s chameleon therefore only lives for three to five months! In contrast, the eggs lie in the ground for between eight and ten months until the next rainy season. Depending on how a rainy season turns out in western Madagascar, the Labord’s chameleon’s entire population may only exist in eggs in the worst-case scenario. A fascinating, but also somewhat creepy idea.

#showyourcolours #internationalchameleonday #chameleonday #chameleondayMay9 #agchamaeleons

Picture: Furcifer labordi male, photographed by Lennart Hudel, Creative Commons Attribution 4.0 International

Lost for more than 100 years

Lost for more than 100 years

by Alex Laube Internationaler Chamäleontag

Did you know that there is a chameleon that was considered lost for over 100 years? Voeltzkow’s chameleon (Furcifer voeltzkowi) was last seen in 1913. Since then, it was considered lost because neither the exact location where it was found nor what the females looked like was known. In fact, the species lived completely undisturbed in western Madagascar on a peninsula directly opposite the large coastal town of Mahajanga. Until 2018, when a German-Madagascan research team set out to rediscover the long-lost species. They succeeded – in a hotel garden! The main reason why the species had not been observed for so long is probably due to the poor accessibility of the peninsula on which they live and the short lifespan of the animals. It is assumed that, like Furcifer labordi, a closely related species, they only live for a few months. They can therefore only be found at a certain time of year.

#showyourcolours #internationalchameleonday #chameleonday #chameleondayMay9 #agchamaeleons

Photos: Furcifer voeltzkowi, male and female, photographed by Alex Laube

The largest chameleon

The largest chameleon

by Alex Laube Internationaler Chamäleontag

The largest chameleon in the world – well, actually several species are fighting for the title. There are three contenders: the Meller’s chameleon (Trioceros melleri) from mainland Africa, the Parson’s Chameleon (Calumma parsonii parsonii) from Madagascar and the Madagascar giant chameleon (Furcifer oustaleti).

The Meller’s chameleon is found in the mountains of Tanzania, northern Mozambique and Malawi. The main distribution area is known to be Mount Zomba. The largest chameleon of this species measured to date is said to have measured 76 cm from the tip of its nose to the tip of its tail and weighed 600 g. The Parson’s chameleon, on the other hand, is found in various places on the central and southern east coast of Madagascar. Here, the largest chameleon measured so far is said to have been 72 cm long, but there are even measurements of over 700 g in weight. The Parson’s Chameleon is therefore definitely heavier, and the size of some animals comes close to that of the Meller’s chameleon. That leaves the Madagascar Giant Chameleon. It reaches almost 70 cm and, despite its sometimes impressive size, it almost always weighs less than 500 g. So despite its name, it will probably have to make do with third place.

#show your colours #internationalchameleonday #chameleonday #chameleondayMay9 #agchamaeleons

Pictures:
Trioceros melleri,  Creative Commons Attribution 4.0 International, photographed by John Lyakurwa
Calumma parsonii parsonii, Creative Commons Attribution-Share Alike 4.0 International, photographed by von Jialiang Gao
Furcifer oustaleti, Creative Commons Attribution-Share Alike 4.0 International, photographed by Sharp Photography

The smallest chameleon of the Earth

by Alex Laube Internationaler Chamäleontag

The world’s smallest chameleon is also the world’s smallest amniote. It is called Brookesia nana – Nano chameleon – and was only discovered in 2021. Given its size, this is hardly surprising – it is only 22 mm long! The male is even a little smaller than the female, which at 29 mm in total length is no giant either. Its home is the island of Madagascar in the Indian Ocean, more precisely in the Sorata Massif in northern Madagascar. It lives in layers of foliage at the foot of large trees. There is another exciting feature: in relation to its body size, the male of this species has incredibly large hemipenes! Yes, chameleons have two penes instead of a single penis – handy if one breaks. But in the nano chameleon, the hemipenes make up 18.5% of the total body length. In humans, that would be the same as if the penis of a 1.80 metre tall man were 33 cm long.

But back to the nano chameleon itself. Despite its tiny size, like many other chameleon species it reproduces by laying eggs in the foliage. These hatch into even tinier young, which feed on the smallest micro-insects on the ground. Overall, however, the tiny creatures are likely to have a relatively hard time in the rainforest, as even any spider is bigger than them and certainly sees a small chameleon as a welcome change on the menu, but in fact the main threat to the small chameleons is humans. The nano-chameleon was probably already threatened with extinction before it was discovered.

The discovery was a pretty big deal at the time. It was reported everywhere, for example in Die Welt, auf National Geographic, bei Scinexx, im GoodNews Magazin oder bei der Frankfurter Allgemeine Zeitung. You can download the original publication for free here. And what we still don’t know: Is there perhaps even a smaller chameleon? After Brookesia minima, Brookesia micra and Brookesia nana, the only thing missing is Brookesia pika. Madagascar has already had a few surprises in store… maybe this one too?

#show your colours #internationalchameleonday #chameleonday #chameleondayMay9 #agchamaeleons

 

Video: EndangeREX, Timon Glaw

New hope for Calumma tarzan

New hope for Calumma tarzan

by Alex Laube Verbreitung Science

Calumma tarzan, the Tarzan chameleon, was only described in 2010. It was named after the place where it was found, Tarzanville, a small village in the Anosibe An’Ala region in the centre-east of Madagascar. Due to the previously assumed very small distribution area, the species was immediately classified as “critically endangered” on the IUCN Red List.

In 2020 and 2021, Malagasy scientists searched for the species in many other places in eastern Madagascar – and promptly found it, as a recent publication reports. They searched 46 transects, each one kilometre long, in 23 different forest fragments. A further 28 transects, each 200 metres long, were examined in order to assess the population density. Calumma tarzan was found in 14 of the 23 forest fragments analysed. None of these occurrences were previously known. The species occurred at altitudes of 604 to 1048 metres. Population density estimates varied greatly. In some areas there are only 25 chameleons per hectare, in others more than three times as many, namely 78.

Only a few of the forest fragments are currently protected. This study therefore emphasises how urgent it is to establish further protected areas in Madagascar’s eastern rainforests. This is the only way to save the Tarzan chameleon.

New distribution records and population density of the critically endangered Tarzan chameleon (Calumma tarzan), eastern Madagascar
Alain J.V. Rakotondrina, Raphali R. Andriantsimanarilafy, Hanta J. Razafimanahaka, Achille P. Raselimanana, Rikki Gumbs, Caleb Ofori-Boateng, Jody M. Taft, Fanomezana M. Ratsoavina
African Journal of Herpetology, 2024
DOI: 10.1080/21564574.2023.2291358

Mosquito bites may induce skin colour change

Mosquito bites may induce skin colour change

by Alex Laube Tiermedizin Science

Sometimes science starts small: last year, someone posted a photo of a Calumma globifer with a mosquito sitting on it on the online platform iNaturalist. Right there you could see a black discoloration of the scales. I wonder if there was a connection?

A handful of curious people searched for more photos of mosquitoes on chameleons and found what they were looking for: On Facebook there were some of Veiled chameleons, on iNaturalist more of Furcifer minor and Furcifer nicosiai. However, there were also six observations of mosquitoes on chameleons that did not appear to have black spots.

To test the connection, scientists in Madagascar placed two Furcifer oustaleti and four carpet chameleons alone in an enclosure with 25 female Asian tiger mosquitoes (Aedes albopictus), which had not been fed for 24 hours beforehand. At the same time, all six chameleons were pricked in the skin with a needle to test whether this “trauma” would also trigger a color change in the skin. The results were surprising: in the four Furcifer lateralis, numerous black skin discolorations developed after mosquito bites, in the two Furcifer outaleti not a single one. The punctures with the needle remained without consequences in all six.

The authors of the recently published article propose three possible theories as to how the color change in the chameleon’s skin could come about: The mosquito saliva could contain a type of local anesthetic, nitric oxide or other proteins that cause the skin’s melanophores to become exclusively visible. Further research in this field would certainly be exciting!

Mosqito bite-induced color change in chameleon skin
Pablo Garcia, Raul E. Diaz Junior, Christopher V. Anderson, Tovo M. Andrianjafy, Len de Beer, Devin A. Edmonds, Ryan M. Carney
Herpetological Review 54(3), 2023, pp.353-358

Chameleons in Bobaomby (Madagascar)

Chameleons in Bobaomby (Madagascar)

by Alex Laube Verbreitung Science

The Bobaomby complex is located at the northernmost tip of Madagascar, north and west of the largest coastal town in the north, Antsiranana (Diego Suarez in French). It consists of dry forest at sea level up to a maximum of 200 metres above sea level as well as extensive savannahs on karst rock and various rock formations. The area has not been protected to date.

Scientists from Madagascar conducted reptile counts in the Bobaomby complex in 2018. The counts were carried out in February and March, i.e. during the rainy season. Five different locations were analysed: Beantely, Antsisikala and Ambanililabe as examples of varying degrees of degraded dry forest, Anjiabe for its intact dry forest and Ampombofofo with relatively intact forest. To find animals, the visual survey was used on 25 days during the day and at night in selected transects, sometimes specifically in suitable habitats such as leaf axils or under dead tree trunks, and pitfall traps along erected fences were also used.

A total of 42 reptile species have been recorded. All of them, except one gecko species, originally only occur on Madagascar, while two other gecko species are now also found on neighbouring islands. There is a small novelty among the chameleons: the leaf chameleon Brookesia ebenaui was recorded for the first time in Bobaomby, more precisely in Beantely. Brookesia stumpffi and Furcifer petteri were found in Beantely, Anjiabe and Ampombofofo. Furcifer pardalis and Furcifer oustaleti occurred as expected throughout the whole Bobaomby complex.

The authors suggest that the Bobaomby complex – especially the three forests where most of the reptiles were found – should be protected to preserve the local herpetofauna.

Overview of reptile diversity from Bobaomby complex, northern tip of Madagascar
Randriamialisoa, Raphali R. Andriantsimanarilafy, Alain J. Rakotondrina, Josué A. Rakotoarisoa, Nasaina T. Ranaivoson, Jeanneney Rabearivony, Achille P. Raselimanana
Animals 13: 3396, 2023
DOI:  10.3390/ani13213396

Photo: Furcifer petteri, male, in the north of Madagascar, photographed by Alex Laube

Lecture in Hamburg about Madagascar

Lecture in Hamburg about Madagascar

by Alex Laube Reiseberichte Live lectures

Together with Jutta Dwinger, AG member Lars Dwinger will be giving a presentation full of pictures in Schleswig-Holstein on Friday, 15th September 2022. Last year, the two travelled to the north of Madagascar, which is known for its extreme biodiversity.

The journey begins in the Marojejy National Park, which stretches across the gorges and steep slopes of the mountain range of the same name. There you can see extremely rarely photographed chameleons, but also a great variety of frogs, snakes and geckos. Afterwards, the journey led via the east coast towns of Sambava and Vohémar to the dry forest of Daraina. The next stop was the world-famous Tsingys in Ankarana National Park. Even in these two dry forests, there is a lot of small and big life. The final stop was camping in the middle of a chameleon paradise: The Montagne d’Ambre in the far north of Madagascar. Between tiny earth chameleons that just fit on the tip of a finger and the gentle giants of the rainforest, the two Hamburgers encounter many fascinating creatures on this trip.

Lars und Jutta Dwinger  Foray through four national parks in the north of Madagascar
Terrarien-Freunde-Hamburg e.V.
Vereinsheim des SC Condor
Berner Heerweg 188
22159 Hamburg
Start of the presentation at 6 p.m.

Picture: Brookesia betschi in Marojejy, photographed by Jutta Dwinger