Speaking of brilliant colors, this species consists of many morphs or "races", each of which effectively mimics the coloration and pattern of another thumbnail dart frog species in its area. This species is an example of Müllerian mimicry, where more than one poisonous species that are not closely related and share predators, develop similar warning signals (in this case, coloration and pattern). For example, the Cainarachi Valley morph mimics Zimmerman's Poison Frog, Ranitomeya variabilis.

 

Several morphs vary considerably, so when it comes to captivity, matters are further complicated by the need to know the geographical origin (locale) of the specimen(s) in question. It is frowned upon to mix morphs and also to mix similar animals that do not share a known geographical collection area, no matter how similar they are in appearance. This is necessary to preserve the genetic line of the originally collected animals, rather than produce hybrids.
 

Like all Peruvian Dart Frogs, the Imitating Dart Frog is protected under Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). This means that export of these animals across international borders requires official CITES paperwork certifying the legality of the original export from Peru. Peru allows small numbers of these frogs to be exported each year by officially sanctioned organizations and companies, such as Understory Enterprises in Canada. Sadly, huge numbers of these frogs have been smuggled out of Peru since the species was first described, and many populations, particularly in mainland Europe, are originally from illegal exports out of Peru. Aside from the direct impact of illegally collecting wild frogs (and the huge numbers that die in the process), without knowing the locale where the frogs were collected, it's impossible to pool their genetic diversity with other captive populations of known genetic origin. Therefore, this author advises you to only acquire legally exported Imitating Dart Frogs of known geographic origin.
 

Imitating Dart Frogs are usually found above the forest floor, climbing through shrubs, trees, and other cover. They breed in the tiny pools of water that form in plants like Heliconia and Xanthosoma. Only males call, and it is a pleasant variation on the call of a cricket (hear the call on Dendrobates.org). Males defend small territories from rivals, and as recently shown by Brown et al. (2010), the lack of natural food in such tiny pools has led to this species becoming completely monogamous - a pair mate until the death of one of the partners. By remaining completely monogamous, the pair ensure that their tadpoles receive adequate food to develop to metamorphosis in their otherwise nutritionally inadequate pools. Food comes in the form of infertile eggs, deposited by the female. The pair keep track of where each of their tadpoles is located, and they regularly check each pool and feed each tadpole as necessary. This is a fascinating behavior to observe in the terrarium, as is the transport to each pool of hatchling tadpoles by their father. Their faithfulness has allowed this species to exploit the tiny, nutritionally poor pools that are unusable to other arboreal dart frogs.

 

Suitability as Captives
The quick facts table earlier in this article describes this species as "Intermediate". The reason for this is that all dart frogs require stable, humid conditions with a relatively unchanging temperature range throughout the year. This is because these frogs originate in equatorial rainforest where the duration of day time, amount of rain, temperature, food availability, etc, remain very consistent from month to month. These frogs also require food on an almost daily basis because they are very active and live in relatively warm conditions. These facts are true for all poison dart frogs, but thumbnails in particular are somewhat more delicate than, say, the Dyeing Poison Dart Frog (Dendrobates tinctorius). Therefore, if you've never kept Poison Dart Frogs before, be especially diligent in your research if you intend to start with thumbnail sized dart frogs. If you are looking for a dart frog you will be able to see at any time of the day, Imitating Dart Frogs should not be your first choice. While they are frequently bold, they have distinct peaks of activity (usually one for a few hours in the morning and one for a few hours before the lights go out), and often spend long periods of time hiding in bromeliad axils and other cover spots. Their small size also makes them harder to spot at times, and, like other thumbnails, they move surprisingly fast and jump amazingly far, and escaped individuals are nearly impossible to locate. Consequently, these frogs should not be top of the list for the casual pet owner, and certainly shouldn't be considered for younger children.

 

That being said, among the thumbnails, few are as bold as this species, and for anyone with some frog experience wishing to try their hand at thumbnails for the first time, they are one of the best choices in terms of boldness and relative hardiness. Keep in mind that it has been scientifically proven that this species is monogamous and, ideally, they should be kept in pairs. While many hobbyists report success with keeping them in groups, this is generally in larger terraria than most used by the novice, and it is generally the more experienced hobbyists who have long term success keeping this species in groups. In numbers higher than a pair, there are often reports of one male dominating the other, thus rendering the second male redundant. There are many reports of these "third wheel" frogs, and "third wheel" females living short lives.

 

Captive Care:

 

This species has been shown to be naturally monogamous, so the most naturalistic number of frogs to keep in a terrarium should be a male and female pair. Having said that, some hobbyists maintain larger numbers in the same terrarium with apparent success. These frogs are not as aggressive as, for example, Dendrobates tinctorius, but the males will wrestle with one another, and on occasion, females have been known to do the same.

 

As a poison dart frog from equatorial rainforest, these frogs require high humidity. This can be accomplished either through a proprietary/custom misting system, or for those of us on a budget, by daily - or almost daily - misting of a terrarium that has restricted ventilation. Misting with distilled water or reverse osmosis (R/O) water is recommended, because tap water and spring water contain dissolved salts that will cause the inside glass to become “dirty” due to the salts precipitating out. By using distilled or R/O water, you will have to clean the glass less frequently. Terrariums with restricted ventilation have a tendency to develop algae on the inside glass, but for many this is an acceptable trade-off when compared to installing a misting system.

 

Day temperatures should be maintained between 21 and 27 °C (70-80 °F). A decrease in temperature at night is recommended in order to mimic natural conditions. A suitable night range for this species is 17-21 °C (63-70 °F). Cooler temperatures may be tolerated for short periods, but many poison dart frogs do not recover their old vim when exposed to temperatures much below 13 ° C (54 °F) for long. Temperatures a little higher than 27 °C will be tolerated for short periods of time, but prolonged exposure to temperatures of 29 °C or higher will usually result in death.

 

I find the 40 L (10 US gallon) glass aquarium to be ideal for a breeding pair of R. imitator. You can read about how I put together the terrariums in the photograph above here. You can buy similar conversion kits online – there is a link to one source in that how-to. Whatever approach you take, I find a drainage layer of LECA (light expanded clay aggregate) or another low density substance sold for this purpose, should line the base of the terrarium. You can purchase these substances from vendors online (such as FrogForum's sponsors), or at reptile and amphibian expos. This layer allows excess water to drain from the substrate above, thus preventing water logging. It also provides a “reservoir” of water to help maintain humidity in the terrarium. I usually include a small length of PVC pipe with holes drilled in the base. This pipe runs from the bottom of the LECA layer through the substrate to the surface, where it is capped with a piece of aquarium filter wool to prevent frogs getting in. This allows me to siphon off excess water if the water level reaches above the LECA. 
 

On top of the LECA I place a piece of fibre glass screen mesh to help stop substrate falling into the LECA layer. On top of the screen mesh I place a layer of coconut husk – just enough to obscure the mesh. This gives added protection against substrate getting through the mesh. The substrate/soil mixture I use is Atlanta Botanical Garden (ABG) mix (developed by Ron Gagliardo under his tenure at the Atlanta Botanical Gardens). I use about 2.5 cm (1 inch) or so in this size terrarium. You can buy this mixture online from dart frog vendors (such as FrogForum's sponsors), or you can follow the recipe and make it up yourself from the components listed at that last link. I introduce springtails to the substrate as decomposers and a food source for young R. imitator frogs (more about that later).

 

The substrate layer is covered with live oak leaves (a species of North American tree with small but slender, blade-like leaves). These last a long time in the terrarium, and their relatively small size makes them easier to form-fit to the small surface at the bottom of the terrarium, around objects like driftwood, etc. Other leaves that last a long time in a tropical terrarium include magnolia leaves (the more southerly US varieties with the thick leaves last longer than the northern varieties), morel leaves and sea grape leaves.
 

Planting terrariums is a field all unto itself, but in this small a terrarium I generally use some small bromeliad varieties that don’t grow larger than 15 cm or so (6 inches). My favourite bromeliad is Aechmea gamosepala, because it has a lot of leaves and holds a lot of water for its diminutive size (most Aechmea species are huge by comparison). I then add some creeping fig (Ficus sp.), a small Aroid or two, and some Java Moss (Vesicularia dubyana) to low areas that receive a lot of light.

 

Lighting for planted terrariums should be in the “daylight" spectrum – approximately 6500 K (light color temperature). I keep my R. imitatorterrariums on a 12/12 hour day/night schedule using an electronic timer. The three terrariums shown in the earlier photograph are lit by four 20 watt spiral compact fluorescent bulbs in an Exo-terra light canopy. They are not special bulbs other than being 6500 K.

 

For R. imitator terrariums, I add a few film canisters as extra refuges and egg-laying sites. I get film canisters and drill a hole in them, then attach a suction cup from the hardware shop. I usually place them in a slightly upward pointing direction so that water can pool in the bottom.

 

Most authorities advise letting a terrarium "grow-in" for a month or two. I'm generally not that patient, and provided the correct materials are used, there is usually no problem in populating the terrarium early.

 

Feeding
Fruit flies have long been the staple food of the dart frog keeper. They are straightforward to culture, easily available through online vendors (such as FrogForum's sponsors) and some local pet shop chains, and aside from the purchase of new media, are a very cheap source of food. You can learn more about culturing fruit flies here. Newly metamorphosed R. imitator can often manage small Drosophila melanogaster fruit flies, but a supply of springtails is a safer bet. If you recall from earlier, I seeded the adult terrariums with springtails so that tadpoles raised in the terrarium have a ready supply of suitably small food after metamorphosis. After a few weeks, young R. imitator can readily take Drosophila melanogaster fruit flies, and adults and large juveniles readily eat Drosophila hydei, a larger species of flightless fruit fly. 

 

It is generally accepted that fruit flies in and of themselves do not make a complete food. Therefore, supplementation is advised. I supplement almost every time I feed. I rotate through four different supplements: Repcal calcium with vitamin D3, Herptivite vitamin and mineral dust, Repashy Supermin vitamin and mineral supplement, and Repashy Calcium+ICB (Instant Cricket Balancer). Supplementing their food supply will lead to faster growing and healthier frogs; not supplementing can lead to vitamin and mineral deficiencies, and even death.

 

Bean Weevils, a type of beetle that can be cultured using beans, peas, or grains, are another food that adults will occasionally take. The are about the size of a Drosophila hydei, but they have a much more chitinous exoskeleton, making them tougher and more difficult to digest. Use them for variety, not a staple food.

 

Breeding
It may wound dart frog enthusiasts to state it, but poison dart frogs as a whole are among the easiest of amphibians to breed. These frogs come from very stable tropical climates that allow them to breed at most times of the year. The only significant variable is humidity, and even then, this really only ranges from humid to extremely humid. Most frogs require seasonal cues and significant environmental triggers like monsoon rains in order to breed. This is not the case for most poison dart frogs, and R. imitator simply requires consistent tropical conditions to trigger breeding. Therefore, if we can provide these conditions in the terrarium, together with egg-laying sites and appropriate pools for tadpoles, these frogs will usually breed and subsequently feed and raise their tadpoles to froglets without any interference from us.
 

For egg laying and tadpole raising sites, small bromeliad species and cultivars are ideal. My favorite is Aechmea gamosepala due to its compact size and good water holding capacity/number of pools, but there are alternatives, such as small cultivars of Neoregelia bromeliads. I like to place bromeliads in the terrarium so that their centers either face straight up or slightly towards the terrarium’s front. The latter allows you to more easily spot eggs and tadpoles but can reduce the amount of water the bromeliad can hold. 

 

I also include a few plastic film canisters (with suction cup attached) in the terrarium as extra tadpole pools and egg deposition sites. In my experience, these frogs will occasionally deposit in the leaf litter and even on the glass. Eggs deposited in leaf litter are nearly impossible to locate unless you keep a close eye on the habits of the male. He will often call from or near to the egg-laying site. The color of the canisters does not seem to be important, but frogs will usually show preference towards those that aren’t as “out in the open” as others. I usually attach mine to the glass with the mouth facing upwards, about 45° from vertical, and I add a little distilled water to the bottom. I often use these as in-terrarium raising containers for tadpoles I have removed from bromeliads and placed in the container myself. More on this later.

 

Males can call as early as 3 months out of the water and I’ve personally witnessed this. When groups of juveniles are maintained together, a keen eye can use the behavior of young males to spot immature females, but this takes practice. Females rarely demonstrate breeding behavior at less than 6 months of age. A mature female is the same size, or more often, larger in size than her mate. Mature females develop a pear-shaped body, widest in front of the hips, and males are rarely much wider at their hips than at their shoulders. In my experience, mature females tend to have a proportionately wider head (the eyes seem wider set than the male). Females of this species do not call, so that in itself is a give-away. If more than one male is present, only one male may call. In order to sex out sub-adult frogs, it can help to maintain each frog in a separate container for a few days, with daily misting, while paying attention for the tell-tale calls. If you have a well fed 5 month old frog that is not calling on its own, it’s more than likely a female.

 

I have been alerted to a recent breeding because the pattern of the male’s calls have changed. Males generally call for a few hours in the morning after lights on, and late in the evening before and just after lights out. Their call is just like the one linked earlier in the article. More subdued calls, calls shorter in duration, and calls closer together in interval are all signs of mating behavior. In fact, absence of calling can indicate something has happened – a male who has just coaxed a successful set of eggs from a female will often stay quiet for a day or two.

 

However, despite the most diligent observation by the hobbyist, R. imitator are notorious for sneaking a clutch of eggs where you can’t see them. I have found one of the dental mirrors sold in pharmacies to be very helpful for spying inside hard-to-see bromeliad axils and I’ve found several clutches in this way. Such a device is also helpful for monitoring egg development.
 

Typical clutch size is 1-3 eggs. Occasionally 4 or 5 are laid, but this is rare. New parents often produce infertile eggs, or eggs that cease development after a few days. They also tend to produce more “delicate” eggs that are prone to fungal infections which don’t affect the eggs of seasoned parents. If you have a young pair that lay for the first time, don’t get your hopes up – it is rare for the first clutch or two to develop successfully. Viable eggs reach hatching at 14-16 days, at which time the male (or occasionally the female) will pick them up individually and ferry each to its own rearing pool.

 

In my experience, most pairs will continue to lay eggs until they have used most of the optimal tadpole rearing pools in the terrarium. In a vertical 40 L (10 US gallon) terrarium, this usually means they will stop laying after they have 8-10 tadpoles in the terrarium. Larger terraria with more rearing sites and space usually mean the parents will have a larger family in progress at any given time. In the small terrarium, after the tadpoles have reached froglet stage (60-75 days), laying usually begins again. When in "laying mode", parents will usually produce a clutch of eggs every 5-7 days, so you will have multiple clutches developing at any given time. 

 

Removing new eggs from the terrarium allows you to side-step any break in laying, but the frogs realize what is going on and tend to hide their eggs, making it more difficult to keep track of all the clutches in order to remove them.

 

Hatching Eggs: My preferred method is to let the eggs develop in the parents' terrarium, even if I plan to raise the tadpoles myself. If you pay close attention, you can see that the tadpoles develop external gills while in their egg jelly, and these are resorbed (that's the correct word) in the days leading up to hatching. If you plan to remove the hatchling tadpoles yourself, before the male can pick them up, do so around day 14 or when you see the gills are gone or almost gone. Doing so earlier is a risky business, unless you remove the eggs right after they have been laid - the jelly loses a lot of its strength during development and it's easier to manipulate the eggs when they are fresh.

 

Hatching eggs outside the terrarium is another option. If you decide to remove the eggs, it's often easiest to remove part of the leaf or the whole film canister where they have been laid. If removing eggs, I prefer to remove just the eggs and jelly. This can be accomplished relatively easily by using the curved butt of a teaspoon that is firmly, and in one motion, rubbed against the bromeliad leaf or film canister wall, such that it dislodges the entire jelly mass. Some people use plastic spoons (the spoon end in this case) but any tool that works for you is fine.

 

A good approach to hatching eggs outside the terrarium is to place them in plastic lunch meat container with a trickle of water in the bottom. The eggs themselves are placed on a piece of plastic (such as the lid of a smaller lunch meat container) which is then placed inside the larger container. The lid of the large container is then put in place, usually with a couple of small holes for a little ventilation in order to reduce the chances of fungus. This setup allows the eggs to be exposed to very humid conditions but not immersed in water. The container is placed in a warm environment so that the temperature is maintained at or slightly above 21-23 °C (72-74 °F). Eggs will develop faster at higher temperatures, but in my experience it is better to stay in the aforementioned range. Some people recommend adding a drop of methylene blue solution to the water used to spray the eggs, in order to reduce the chances of bacterial or fungal problems. In my experience with R. imitator, eggs from seasoned parents do not require this interference and I do not use methylene blue.