September 2021 Species spotlight – Fantastic Frogs & Mythical Creatures

Golden Mantella

Mantella aurantiaca, or Sahona mena in Malagasy is one of, if not the, most iconic of Madagascar’s amphibians and a species with which I (BB) have a real obsession, so be warned this could be a long one!

Found only in the eastern forests of Madagascar the species is now restricted to a handful of mid altitude forest fragments (800-900m asl) here the species is found around seasonal and permanent pools where the species will court mate and breed.

In the wild this species is a seasonal breeder making use of both permanent and seasonal breeding ponds, outside of the season the frogs disperse into the forest and are trickier to find but at the onset of the rainy season, in the lead up to cyclone season, the frogs begin to aggregate around these pools some of which are little more than ditches with others flooding to form lakes or even series of channels running amongst the forest trees.

Active from very early in the morning the frogs can be seen hunting for food as well as calling and courting, but by the time the sun reaches its peak and the temperature, even in the shadows of the canopy, begins to heat up the frogs are hiding deep amongst the leaf litter.

Despite being a critically endangered species the Golden Mantella is probably the most commonly kept Mantella species in captivity, this is due to a combination of factors the first being, it’s desirable, vivid orange in colour it is comparable to a poison frog, secondly they can reproduce in large numbers, clutches of 50 are easily attainable and the most important factor, they are pretty easy to breed as long as you keep to the basic rules. In the wild the species probably only spawns once or maybe twice a year unlike poison frogs and there are a few more factors that differ in terms of their husbandry which make them a bit more challenging at times.

Temperature is the big difference, Mantellas, as a rule, do not tolerate prolonged high temperatures very well, and despite temperatures in the wild reaching upper 30°C’s it is usually only for shortened periods whilst they are active and it always drops down again at night, in fact at times the temps drop to 15°C and in the winter they can drop as low as 10°C. In captivity the temperature range does not need to be as extreme but they are seasonal breeders and so replicating some sort of season is quite important. in fact a winter night time drop regime of 16°C is probably a good plan as it will help condition the frogs ready for the following years breeding season. Day time highs during this cool period should sit at around 21-22°C with the breeding season temps being 20°C and 25°C respectively.

Humidity and rainfall is a bit different to, as previously mentioned there are more distinct seasons in Madagascar, including a cyclone season which brings immense amounts of rain to the region, this tends to be the prequel to the breeding season and floods many of the seasonal ponds, there is also a much drier season during which time the frogs are restricted to the forests alongside permanent water bodies and deep in the forest amongst the dense leaf litter. Here, even during the dry season, the frogs can find areas of locally high humidity, but often with very low rainfall, this contrasts dramatically to the wet season where rainfall is daily and can persist for 8 hours at a time.

In terms of captivity this can be hard to replicate but in our facility we reduce misting over winter to one short period a day and ensure the enclosures water source is kept topped up, during the summer season this increases to 3 times a day but for prolonged periods, one early in the morning and then two heavy misting periods in the afternoon. Again we ensure the water bodies are kept topped up although they actually need to be drained a few times over the season to prevent flooding.

Socially Mantellas in general are a bit different to Dart frogs in that they really prefer to be in large groups, a viable breeding group would consist of several males to call against one another and then multiple females so multiple spawnings can be achieved, I try to aim for groups of around 5.5+.0 in fact a group of 5.10.0 will be a very productive group but in the past I have maintained groups closer to 10.40.0 without there being any issues (apart from the amount of food they eat). Males tend to call from raised points in the vivarium until they have the attention of a female and then lead them to a suitable spawning site, usually beneath a piece of bark or a large leaf, or if possible under moss in a cave they excavate themselves!

Once the female has entered the spawning area the male will loosely amplex the female, frequently other males and occasionally females try to get in on the action and clutches can consist of eggs fertilised by multiple males.

The spawn develops quickly and within a week the tadpoles can be clearly seen wriggling away in the spawn mass. in the wild rainfall washes the tadpoles into pools and ditches but in captivity we tend to remove the spawn and once the tadpoles begin to free themselves from the eggs we wash them out into a shallow aquarium filled with Java moss and guava leaves.

The tadpoles develop quickly if fed enough and water quality maintained, we use a carotenoid enriched fish food which helps maintain the natural colour of the adult frogs. As soon as they have 4 legs the tadpoles are removed to an emerging enclosure where they can leave the water when ready and begin to feed.

Mantellas are hungry frogs, like dendrobates they can feed almost all day long, however they may be dart frog sized but they have bigger teeth and a desire for larger food, now I’m not saying they’ll eat adult crickets but they are definitely capable of handling much larger food than a similar sized dart frog, we use springtails for newly metamorphosed froglets but quickly they move onto Drosophila, adults also receive drosophila, as well as pea aphids, hatchling crickets, 1st crickets, grain weevils and bean weevils, in fact the grain weevils and crickets are probably essential to gain good breeding results, the high calcium content of the weevils is very similar to the food items they would eat in the wild and although at first they often appear to spit them out pretty quickly they recognise them and go crazy when they are offered them.

As a captive frog the Golden Mantella is a very easy species to keep given the right parameters, it’s also probably the easiest of the Mantellas to spawn, the eggs are more forgiving of environmental parameters than most of the other species, and they are always active, constantly on the go looking for food.

In the wild however the story is different, the pressures on the species are much like those faced by frogs all over the world, habitat loss, not just for farming, but deforestation for charcoal production, pollution by attempts at gold mining, sapphire mining, and the wholesale destruction caused by vast mining operations in search of Nickel and Cobalt for the manufacture of rechargeable batteries for high end tech, add to this the presence of Batrachochytrium dendrobatidis and the future is sketchy to say the least.

However there are people working to help these iconic frogs, check out the work done by Madagasikara Voakajy with assistance from Chester Zoo, Home – Madagasikara Voakajy (madagasikara-voakajy.org).

Golden Mantella habitat and a few of the locals!

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