Introduction
These relatively small (20 – 50mm), very colourful
and active frogs are currently split up into four general
- Dendrobates, Phyllobates, Epipedobates
and Minyobates. There are currently sixty-five recognised species, but
new species and sub-species are still being classified. They are often
referred to as poison arrow or poison dart frogs but this is misleading
due to the fact that only three species (Phyllobates terribilis, P. bicolour
and P. aurotaenia) are known to be used by American Indians to tip the
darts for their blowguns. Poison frogs make fascinating terrarium inhabitants,
being fairly easy to keep and active during daylight hours (diurnal).
Nowadays many species are captive-bred. Such specimens
can be a better choice, especially
for beginners, than imported animals which can be difficult to acclimatise.
Distribution
Poison frogs inhabit mostly humid rainforests of South and Central America,
ranging from Nicaragua in the Northernmost range, down to Peru through
to Bolivia / Paraguay borders in their southern-most range. Most species
live in warm valleys, but some have been found in cooler mountain forests
at altitudes of up to 2000m.
Description
These extremely colourful, and highly variable, frogs come in virtually
all the colours of the spectrum, from bright reds (Dendrobates pumilio),
to bright green and black (D. auratus) to bright blue (D. azureus).
Not all are as brightly coloured but all are very beautiful in their
own ways. There are also many colour variations within a single species.
This is clearly illustrated by Dendrobates tinctorius and D. auratus,
which have numerous forms ranging from very dark with flashes of yellow
and green to vibrant yellow frogs with blue legs (D. tinctorius citronella).
Other species, such as Dendrobates. pumilio, are also highly variable.
Sexing can be difficult in younger frogs but, as a general rule, males
are often smaller than females, have thicker toes and their vocal sacs
can often be seen as a small greyish area on the throat.
Captive care
Selecting your frog
Always select frogs which are in good condition. Do not be tempted to
purchase sick or skinny frogs as these will inevitably die. Many people
make the mistake of taking such specimens home, hoping to pull them
around. Unfortunately this rarely happens, so be sure to pick animals
which look healthy and which appear to be feeding. Imported animals
are available on occasion but these can often be difficult to acclimatise,
so it is probably best to select captive-bred frogs.
The larger species such as Dendrobates auratus, D. tinctorius and D.
leucomelas feed on a much larger variety of foods than the smaller species
and will take small crickets as well as fruit flies, so these are probably
better for beginners.
Terrarium equipment
As a general rule, most poison dart frogs inhabit lowland areas and live
amongst leaf litter and in small burrows, although some species are
more arboreal and will inhabit Bromeliads growing higher up on tree
stumps. This habitat is relatively easy to recreate in the terrarium.
Temperatures in the rainforests do not often vary that much and in
captivity a maximum day time high of 25 degrees C and night time low
of 20 degrees C should be a guide. As with most amphibians, a slightly
lower temperature will do far less harm than excessively high temperatures.
All-glass terrariums with mesh ventilation at both top and bottom generally
work well as they provide adequate air circulation and prevent air from
stagnating but also allow the necessary humidity. Many substrates can
be used (bark chips, sphagnum moss are two commonly used examples) but
I find tree fern slabs (Xaxim) covered with leaf litter works well. I
provide pieces of cork bark for my animals to use as hides.
Daily misting provides the necessary humidity to prevent the skin of
the frogs from drying out and can also aid in plant growth, especially
Bromeliads. Bromeliads can make an attractive decorative feature and
can serve well as retreats and breeding areas for many species. Planting
your terrarium with real plants makes it into a real focal point and
provides an excellent and naturalistic habitat for the inhabitants. If
you do not want the extra work of maintaining real plants an excellent
range of artificial alternatives are now available from most good reptile
shops. It is a good idea to provide a shallow water bowl, but make sure
that the frogs can climb out easily and that the depth does not exceed ½ inch.
These measures should prevent accidental drowning.
Poison frogs should be exposed to a 12 hour day / night light cycle,
a fluorescent light connected to a timer will produce a natural lighting
source and will aid plant growth.
Feeding
Poison frogs eat large quantities of very small prey, so ensure that
you have access to sufficient foodstuff. Ants are the preferred food
source in the wild, but captive animals will feed readily on fruit
flies and micro crickets. Smaller species and young froglets will accept
springtails and other small aphids. Most foods are readily available
at local pet or reptile specialists, but fruit flies and springtails
are easy to cultivate yourself if supply is difficult. A good vitamin
and mineral supplement should be used on a weekly basis.
Breeding
Poison frogs are readily available as captive bred animals, reflecting
the fact that captive breeding is not overly difficult. Adults are
often very territorial so it is best not to overcrowd the animals.
Two to five animals will make a suitable size breeding colony. Most
frogs will be sexually mature at around fifteen months of age and many
species will to some extent be sexually dimorphic at this age. Males
tend to be somewhat more slender and have pads on the front toes.
Make sure your frogs are in optimum condition before attempting to breed
from them. Increasing humidity, such as regular misting with luke-warm
water can trigger many species to breed. Make sure the terrarium requirements
match the needs of your frogs for breeding. Some species lay their eggs
in bromeliad funnels, whereas others will lay eggs in streams or pools
of water.
I find covering a petri-dish filled with water with a coconut husks
works well with some species. A small hole cut in the top of the husk
will provide access and should be just large enough to allow the frogs
to pass through. A leaf should be placed in the dish and will be used
for depositation of the eggs. A cheap and easy alternative to a coconut
husk is to cut the bottom off a soft drink bottle and cut a small access
hole, but do ensure that there are no sharp edges.
Once the adults have become used to the nesting site the male will lead
the female inside where mating will take place. Disturb the frogs as
little as possible during the mating period. Up to fifteen eggs will
be laid, hopefully on the leaf provided.
If the eggs are left in situ the parents will tend them but most keepers
remove the eggs for incubation. The incubation temperature is actually
the same as the adult frogs are maintained at so leaving them in situ
is not necessarily a problem. The main problem associated with eggs is
fungus. This can largely be avoided by regular checking and removal of
infertile eggs as the "go off". All things being well, the
tadpoles should hatch in about fifteen days.
Most Phyllobates and Dendrobates species can be raised on fish flakes
and defrosted gnat and mosquito larvae. Tadpoles can be reared in shallow
aquaria with adequate filtration and suitable plants, but be aware of
cannibalism.
After about twenty-five days, the hind-legs should start to develop
and at around forty days the colour and pattern will begin to show. At
around fifty days, the front legs will appear and the tail will start
to be absorbed. Once metamorphosis starts to take place the froglets
should be segregated from the tadpoles. A tank, or plastic container,
with a gentle slope, facilitating a wet and dry area makes the most suitable
habitat for the juvenile frogs. At this stage cannibalism is no longer
a problem and the young can be raised together. Froglets can be reared
on springtails, fruit-flies and micro-crickets.
Conclusion
Poison frogs are extremely attractive, relatively easy to cater for and
make fascinating captives. The sheer variation in the different species
will ensure that every frog lover will have their own personal favourites.
The fact that they are diurnal makes them ideal for densely planted
terrariums and their willingness to breed in captivity will ensure
that their popularity will increase for years to come.
In my opinion they are without doubt the most attractive and interesting
amphibians you could wish to keep.
References and bibliography Heselhaus, R. (1988) Poison arrow frogs
Their Natural History and Care In Captivity. Stuttgart. Eugen Ulmer
GmbH& Co
Walls, Jerry G. (1994) Jewels of the Rainforest – Poison Frogs
of the family Dendrobatidae. Neptune City. T.F.H. Publications, Inc.
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