Actually, Madagascan Mantellae all look very similar: Striking colours, small and slender, terrestrial frogs. But one steps out the line: The climbing Mantella (Mantella laevigata). This Mantella was described in 1913 by British zoologists Paul Ashleyford Methuen and John Hewitt, who did a seven months lasting expedition to Madagascar two years ago. The climbing Mantella grows up to maximally 29 mm and wears bright yellow colour at head and back, as well as blue spots on hands and feet. The rest of the frog is brownish black – so far, so similar to other Mantella. The colour is thought to repel natural enemies, such as birds or chameleons, and signals poison. Indeed Mantella produce a poisonous alcaloid in their skin, but it is completely harmless for humans.
Especially the island Nosy Mangabe, part of Masoala national park, is famous for its high incidence of climbing Mantellas. In March and October, you can watch these small frogs during the day en mass along the thick foliage layer, on tree trunks and mossy stems around the island. It occurs also in Marojejy national park, Mananara and Tsararano, but you will have much more difficulties to find a climbing Mantella there. It inhabits no other places worldwide.
The climbing Mantella is probably one of the best researched Mantella of Madagascar, surely thanks to its for Mantella unusual lifestyle. Indeed it is a terrestrial frog of rainforests like all Mantella, but in contrast climbs trees. It has been found up to four metres in height! Additionally, climbing Mantellas do not need streams or running water to reproduce and survive: That seems to be incredible for such a frog.
During breeding season at the beginning and the end of the rainy season, every male calls loudly at a egg laying place he selected himself. The call attracts females – but also other males. If another male approaches the chosen tree whole, they tend to fight for the place. Who defended his tree whole and a female successfully, fertilizes his Mantella’s eggs after a short amplexus. Egg laying is distinctly contrary in the climbing Mantella than in others of its kind: Instead of hiding a bunch of eggs deep in the foliage, the females glues only one egg – sometimes even two – some centimeters above the water in a small, water-filled tree trunk or bamboo hole. Sometimes the eggs dry out by the sun. But in those which develop successfully, you can watch an embryo from the second day on.
After some weeks, the tadpoles hatches and directly falls into the water beneath. It feeds on everything small enough that falls into the tree hole or bamboo trunk. Often the female climbing Mantella brings unfertilized eggs to its offspring as food. The male climbing Mantella rests nearby and defends the hole against intruders. Thus Mantella laevigata is the only Mantella of which we know such a parental care behaviour. It takes almost two months to grow from a tadpole to a complete frog, they are not full grown before on year. The adult climbing Mantellas feed on ants, termites and mites, but do not reject other tiny insects like flies.
IUCN lists this species as “near threatened” on its red list – together with the hint, that it might be on a higher threatening level in some years. The habitat of this small frog today is not larger than 20.000 km². Scientsists assume that this species cannot survive in destroyed areas after slash-and-burning or where cattle grazes. Only shelters like the island Nosy Mangabe will be able to keep this wonderful Mantella, so that people can gaze at it even in one hundred years from now. Since some years, the species has been keeping and breeding in captivity outside Madagascar successfully, too.
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Showing posts with label Tsararano. Show all posts
Showing posts with label Tsararano. Show all posts
Sunday, 13 March 2016
MADAGASCAR: Guibé’s Mantella
You think poison dart frogs exist only at the Amazon? You are miles out! Madagascar has amphibians very similar to those, the Mantellas or coloured frogs. Like poison dart frogs, Mantella frogs produce a poison secreted via their skin, but it is completely harmless for human beings. Genetically, the Madagascan Mantellas are not related to poison dart frogs.
Mantella frogs are conspiciously colorful despite their small body size. One of these animals is Guibè’s mantella, scientifically called Mantella nigricans. This small frog derived its name by French herpetologist Jean Guibé, who did research on frogs and reptiles from 1950 to 1951 in Madagascar. But it was not before 1978, three years after Guibé got into retirement, that he described the frog for the very first time. For decades, scientists thought it to be a subspecies of Mantella cowani, a similar coloured frog. In the year of Guibé’s death, in 1999, German biologists proved Mantella nigricans to be an own species. Unfortunately, Guibé did not gain knowledge about this fact anymore.
Mantella nigricans in the rainforest of Marojejy
Guibé’s mantella comes from the primary rainforests of northwest Madagascar, and occurs in several national parks: Marojejy, Anjanaharibe Sud, Manongarivo as well as Betampona and Tsararano are among its habitats. One can find it at elevations of 100 up to 1240 m, but it does not live close to the sea or in areas with many human settlements, cattle grazing or disturbed forest residues. Guibé’s mantellas live in the wet foliage, on mossy ground and along small streams. It measures less than three centimeters from the nose to its butt, but fascinates with its amazing bright green color on head, arms and legs as well as bright blue spots on the belly. The Latin name nigricans, which means as much as blackish in English, indicates this mantella wears more black in contrast to other mantella species.
Especially during rainy season, you can hear the males calling in the forests. After mating, the female lays about 30 whitish, spherical eggs, sometimes more, hidden in wet leaves. After one week, the small tadpoles hatch. Rain and humidity lead them to the nearby pond, where they develop until metamorphosis, during which they lose their tails and become terrestrial, as a ready Guibé’s mantella. They feed a whole lifetime on tiny ants, mites, flies and other insects.
Due to its beautiful colour and activity during daytime, Mantella nigricans has been a much sought-after animal for years in Europe, but offspring in captivitiy has been rare yet. Since some years, there exist no exports of this species anymore, probably attributed to its occurence mainly in protected areas. IUCN lists Guibé’s mantella as „least concern“ on its red list of threatened species. It is assumed that there are still relatively large populations of this lovely forester in Madagascar. But if you want to find it, you will need to be patient: Guibés mantella hides well in the forest, and despite the jazzy colour, these frogs are not easy to find.
Mantella frogs are conspiciously colorful despite their small body size. One of these animals is Guibè’s mantella, scientifically called Mantella nigricans. This small frog derived its name by French herpetologist Jean Guibé, who did research on frogs and reptiles from 1950 to 1951 in Madagascar. But it was not before 1978, three years after Guibé got into retirement, that he described the frog for the very first time. For decades, scientists thought it to be a subspecies of Mantella cowani, a similar coloured frog. In the year of Guibé’s death, in 1999, German biologists proved Mantella nigricans to be an own species. Unfortunately, Guibé did not gain knowledge about this fact anymore.
Mantella nigricans in the rainforest of Marojejy
Guibé’s mantella comes from the primary rainforests of northwest Madagascar, and occurs in several national parks: Marojejy, Anjanaharibe Sud, Manongarivo as well as Betampona and Tsararano are among its habitats. One can find it at elevations of 100 up to 1240 m, but it does not live close to the sea or in areas with many human settlements, cattle grazing or disturbed forest residues. Guibé’s mantellas live in the wet foliage, on mossy ground and along small streams. It measures less than three centimeters from the nose to its butt, but fascinates with its amazing bright green color on head, arms and legs as well as bright blue spots on the belly. The Latin name nigricans, which means as much as blackish in English, indicates this mantella wears more black in contrast to other mantella species.
Especially during rainy season, you can hear the males calling in the forests. After mating, the female lays about 30 whitish, spherical eggs, sometimes more, hidden in wet leaves. After one week, the small tadpoles hatch. Rain and humidity lead them to the nearby pond, where they develop until metamorphosis, during which they lose their tails and become terrestrial, as a ready Guibé’s mantella. They feed a whole lifetime on tiny ants, mites, flies and other insects.
Due to its beautiful colour and activity during daytime, Mantella nigricans has been a much sought-after animal for years in Europe, but offspring in captivitiy has been rare yet. Since some years, there exist no exports of this species anymore, probably attributed to its occurence mainly in protected areas. IUCN lists Guibé’s mantella as „least concern“ on its red list of threatened species. It is assumed that there are still relatively large populations of this lovely forester in Madagascar. But if you want to find it, you will need to be patient: Guibés mantella hides well in the forest, and despite the jazzy colour, these frogs are not easy to find.
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