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dart frog

(Cliff1066 via Getty Images)

 

By Leif Simmatis

Imagine your perfect pet.  Is it fluffy?  Cute with a wet nose?  Needs to be housebroken?  Now imagine your landlord’s reaction when you go out and get one of those for your bachelor apartment.  Suddenly, Fido or Sylvester seems less appealing and an alternative is necessary.  Budgies?  They squawk.  Fish? OK, done!

That is, unless you want to stand out a bit.  In this case, perhaps a small reptile or amphibian is a consideration.  There are a vast array of both wild-born (not recommended) and captive-born reptiles and amphibians available at Kingston’s pet stores.  But none, I guarantee, will spark a conversation as fast as the poison dart frog.

Of course, saying “the” is a massive misnomer.  Dart frogs are a colossally diverse family originating in Central and South America, with over 175 recognized members so far.  Dart frog species are surprisingly different, in spite of the fact that many of them may look similar to the uninitiated.  Take, for example, Phyllobates vittatus and Hyloxalus azureiventris: both have a blue set of hindquarters and a brilliant orange/yellow snout on a black skin. However, whereas P. vittatus is found widely in Costa Rica, H. azureiventris is known only sporadically throughout Peru and San Martin, representing a vast geographic separation.

 

The most striking part about poison dart frogs, besides their colouration, is their production of poison. That being said, their poison production is not nearly as potent or prolific as in the cases you may have heard.  The use of dart frogs by South American tribes to poison-tip their blow darts is part of this misconception.  Out of all of the species known, only four have been identified as ever being used for making weapons.

These were effective tools, but the extent of the practice is widely exaggerated.  The four frogs on record as being used this way all belong to the Phyllobates genus, with the standout being P. terribilis.  This frog in particular produces a potent toxin known as batrachotoxin, which affects the heart and nervous system.  An average fatal dose for a human is only 1.6 milligrams of this poison; by comparison, a fatal dose of black widow spider venom is 7.5 milligrams.  All members of this genus produce this poison, but in variable amounts.

P. terribilis happens to produce far more than others, though: it is so prolific that the arrow can be scraped along its back to get enough poison to make the dart lethal (each frog has an estimated 500-1000 milligrams on its skin at any given time). In contrast, other members of this genus have to be roasted to extract poison.

Other types of dart fogs have not been documented in producing such a nasty substance at this amount.  That is not to say that most dart frogs are not poisonous, though.  After all, a defence mechanism is something that the tiny dart frogs need to avoid being eaten on their daytime hunting expeditions (they hunt during the day because they are cold blooded and so the extra warmth allows them to be more efficient).

 

However, pet owners need not be concerned about even the smallest amount of poison.  This is because the poison that they secrete is a product of their natural diet: certain insects (one family of beetles, mostly) contain toxins that the frogs ingest and concentrate before they secrete them.  However, captive dart frogs do not have access to these insects.  The typical diet for a captive frog is usually crickets or possibly small waxworms.  Thus, captive-bred frogs have never produced poison in their lives.

This change in diet has no effect on their brilliant colours, though.  In fact, captive-bred dart frogs come in many different patterns and colour schemes called “morphs”.  These can vary widely even within a single species, to the point where two morphs of one species may look more different than two altogether-separate species.

This variability is what makes them such an attractive proposition as pets.  Prospective owners can choose from nearly any imaginable combination of colours and patterns, and some species of frogs can even be combined together in the same enclosure.  This is a risky proposition, though, unless adequate enclosure space is provided.

A rule of thumb for dart frog enclosures is, for a standard “tall” tank (referred to as a “vivarium”), 5 gallons per frog should be provided.  Other vivarium conditions should be carefully monitored to keep the frogs healthy.  Temperature and humidity are key amongst these.  Given their tropical nature, one would expect that dart frogs would require higher temperatures but this is actually not the case.  Approximate daytime high-temperatures should not exceed 26 degrees Celsius (around 80 Fahrenheit) and night temperatures should drop to approximately 20-22 degrees.  Frogs that are too hot will “gape”, that is, they will sit with their mouths open and appear to do nothing.

Humidity is also quite important, as dart frogs (along with most other frogs) absorb most of their hydration through their skin.  Ideal enclosure humidity should be in the range of 90%, which is quite high, but understandable, that they hail from rainforests.

However, other things besides temperature and humidity should be carried over from their rainforest homes. For example, it is common practice for even small enclosures to contain live plants and working waterfalls, which provide not only additional beauty to the tank but also help stimulate the frogs to both be active and also seek hiding places.  Frogs deprived of hiding spaces can easily become stressed, which can be fatal.  One thing that can obviously not be carried over easily is their highly specialized diet (given its implications for the production of poison, it may not be wise to attempt regardless).

There are other illness factors that can plague dart frogs aside from simple stress, though.  Parasites can occur, and dietary deficiencies can be quite dangerous.  Particularly a lack of calcium or too much phosphorus, both of which can cause Spindly Leg Syndrome, a chronic weakening of the bones that can become fatal.

Do not be dismayed by these complications, though. Any pet requires proper care and maintenance, be it a frog or a dog.  In this case, the requirements are simply a little bit different than what most people might be used to. •

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