- Dart frogs as Pet :
1- TOP 20 REASONS WHY POISON DART FROGS MAKE THE PERFECT PET FOR THE VIVARIUM...
South America's rainforests have been cut back (Credit: Arco Images GmbH/Alamy)
Introduction to the poison dart frogs :
- Poison frogs :
courtesy to : nationalzoo.si.edu/animals/poison-frogs
Genus and Species: various species
As a group, the most brightly colored frogs in the world, poison frogs (also called poison dart frogs or dendrobatids) these frogs live in wet tropical forests in Central and South America where their diet contributes to the toxins they secrete through their skin. Three species are on exhibit at the Smithsonian's National Zoo: the green and black poison frog, tri-colored poison frog and blue poison frog.
FUN FACTS :
- Poison frogs are commonly called poison arrow and poison dart frogs due to native Indian tribes reportedly rubbing their arrow tips on the frogs' backs before hunting. However, only three species have been documented as actually being used for this purpose, including the golden poison frog, the most toxic of all frog species.
- All three of these documented species belong to the genus Phyllobates and not Dendrobates, the genus that includes the most brightly colored of poison frogs that are most often recognized as "poison dart frogs."
Physical Description :
Dendrobatids are commonly known as poison arrow and poison dart frogs due to native Indian tribes reportedly rubbing their arrow tips on the frogs' backs before hunting. However, only three species have been documented as actually being used for this purpose, including the golden poison frog, the most toxic of all frog species. Much medical research is now being done with the alkaloid toxin, batrachotoxin, that the golden poison frog secretes. Researchers are trying to develop muscle relaxants, heart stimulants and anesthetics from the batrachotoxin.
It is interesting to note that all three of these documented species belong to the genus Phyllobates and not Dendrobates, the genus that includes the most brightly colored of poison frogs that are most often recognized as "poison dart frogs."
Poison frogs are known for their beautiful colors, and amphibians that have toxic skin secretions tend to have bright warning colors or patterns. It is theorized that these colors function as a visual warning, a learned response on the part of the predator. A predator that finds a certain kind of amphibian to be distasteful will associate the warning color with the bad taste and after one or more such experiences, will recognize the distasteful species and refrain from attacking. Aposematic coloration usually involves red, orange or yellow. Some animals have bright coloration that does not correlate to toxicity, presumably mimicking those animals in which color truly is a warning.
Poison frogs are generally small species, about 0.75 to 1.5 inches (20 to 40 millimeters) in length.
Poison frogs can be heard calling in the flooded forest. Most species of frogs have well-developed vocal structures capable of producing a variety of sounds that serve to attract mates, advertise territories or express distress. Sound production is often the most common form of communication in animals that jump or fly because they would otherwise have a difficult time communicating by scent. Frogs produce sounds using their laryngeal apparatuses (larynx/vocal chords) and most males have vocal sacs that function as resonating chambers. Species of frogs can be identified based on their calls.
Food/Eating Habits :
Poison frogs feed mostly on small insects such as ants and termites, which they find on the forest floor. Many species capture their prey by using their sticky, retractable tongues. Scientists believe that poison frogs gain their poison from a specific arthropod and other insects that they eat in the wild and that these insects most likely acquire the poison from their plant diet. As a result, poison frogs in human care on a diet of crickets and other non-poisonous insects are not poisonous themselves.
Most species have omnivorous tadpoles that will eat all sorts of food from algae and detritus to insect larvae and dead insects. Some species tend to be more carnivorous (such as the tri-colored poison frog) and eat insect larvae and other tadpoles. Females of some poison frog species place individual tadpoles in water in bromeliads and then periodically return to the site of each tadpole and deposit unfertilized eggs, which the tadpoles eat.
At the Zoo, they are fed small crickets, bean beetles, black worms and/or fruit flies daily and as a result, are not poisonous. Occasionally insects are coated with vitamin powder for extra nutrition.
Reproduction and Development
In wet tropical rainforests, both sexes breed throughout the year, with rainfall being the primary factor controlling the timing of reproductive activity.
Poison dart frogs display elaborate and diverse courtship behaviors. In general, the male will lead the female to a site that he has chosen to lay the eggs. Most of these species of frogs deposit their eggs inside leaf-litter, where it is dark and moist. At the Zoo, keepers make an artificial breeding "hut" for the frogs. Some species also deposit their eggs in bromeliads.
Courtship behavior can last for several hours and normally, the pair visit several deposition sites before they start mating. Courtship continues at the deposition site where the frogs start a mating "dance" consisting of mutual stroking and cleaning of the surface of the leaves.
Poison frogs' clutch size varies between species from one to 40 eggs per clutch. After the eggs are laid, the male fertilizes the clutch. However, in some species, the male releases his sperm before the eggs are laid. The pair will usually guard the eggs to make sure that they do not dry out.
After about ten to 18 days and depending on the species and temperature, the eggs have matured into tadpoles. Either males or females remain with, or periodically visit, the nest. All poison frog species carry their tadpoles on their backs. The adult sits in the remainder of the gelatinous egg clutch and the tadpoles will wriggle up the hind limbs and onto the back. The adult carries the tadpoles to a small stream, pool or other small body of water. Some species transport whole clutches at one time and are completely covered with tadpoles, others transport them one by one or only a few at a time. After several months, the tadpoles go through metamorphosis and become adult frogs.
Poison frogs are mostly diurnal.
Poison frogs in general can live for over ten years in human care. The tri-colored poison frog will live from 12 to 20 years.
1. They are non-toxic!
That's right, they're not poisonous...at least not in captivity. Scientists are fairly certain that a component of the dart frogs diet in the wild is what enables the frogs to be poisonous since captive bred animals never develop toxicity. Additionally, wild caught animals will lose their toxicity after some time in captivity.
2. There's no poop to clean up!
This is a REALY BIG plus for anyone keeping a pet. When kept in a naturalistic type of vivarium, the waste is decomposed by beneficial bacteria within the soil. Unlike many other reptiles or larger amphibians, the waste product of poison dart frogs is so small that the plants can easily break it down.
3. Their colors are naturally vibrant!
The vivid colors and exotic patterns the frogs display serve to warn would-be predators, however they are also stunning to look at! Virtually every color in the rainbow is represented by these living jewels.
4. They are awake and active all day long.
Their diurnal habits allow you to enjoy their behaviors when YOU are awake. Unlike tree frogs which sleep all day long, you won't have to wait until the lights go out to observe their fascinating behavior.
5. They are long lived in captivity.
Well cared for animals can easily live into their teens!
6. They are easy to keep.
When provided with the proper habitat and diet they are very hardy animals. They do not have difficult housing or feeding requirements and require little daily maintenance. Many people compare them to a land version "reef tank" but needing only a fraction of the care.
7. They impact their habitat very lightly.
The perfect compliment to tropical rainforest habitat, dart frogs do not trample the plants and decor in their terrariums. They will not dig, chew, claw or othewise "tear up" their home as many other herps would. A beautiful habitat will not only serve as a focal point for your home or office but will also serve as the perfect habitat for these exotics.
8. They are inexpensive to feed.
A supply of food lasting several weeks costs less than $10 and can easily be purchased by mail order. Culturing flightless fruit flies on your own is easy to do and will reduce the cost to a fraction of that. Supplementation with other small food items should be done whenever possible.
9. They have small enclosure requirements.
Some species are at home in Ten-Gallon terraria while most will be happy in a twenty. This makes them highly desirable by people wishing to keep them in an apartment, home, classroom or at the office.
10. They are not removed from the wild in large numbers.
The vast majority of dart frogs offered for sale to the public have been completely sustained by populations bred and raised in captivity. By choosing captive bred animals you will get a healthier animal as well as reduce the demand for imported stock.
11. Naturally more healthy due to captive breeding.
Captive bred animals do not have the same health risks as imports such as parasite/protozoan loads or bacterial and fungal infections. By buying captive bred animals you know the age of your pet and have the sense of satisfaction knowing you are getting the healthiest exotic pet available.
12. Most can be kept at room temperature.
Temperatures from the low or mid to upper 70's are the preferred range for most species. While most dart frog keepers won't have to worry about simple heating or cooling solutions, others may find it necessary to prevent temperatures from reaching the upper 80's.
13. Many are considered easy to breed in captivity.
Most species commonly avilable can be bred even by beginning hobbyists! Breeding your own froglets is rewarding and will allow you to trade or sell your offspring.
14. They require minimal daily/weekly maintenance.
Maintenance consists of daily feeding, terrarium spraying several times a week and occasionally trimming plants or cleaning the glass every few weeks. Best of all...there's no poop to clean up!
15. They are easily shippable.
Acquiring your new pet is easy as they stand the stress of shipping quite well when packed properly. We have many years experience shipping live frogs and take every precaution necessary.
16. They don't call at night.
Being active in the day means they don't keep you up at night! (Many keepers of tree frogs have had the unexpected or unwanted midnight wakeup calls!)
17. Some have pleasant calls.
Although many dart frogs have nearly silent calls, several species have very musical calls ranging from rapid chirps to long trills that maybe heard across the room.
18. They are educational.
More and more schools are starting to keep them as the perfect teaching aid when discussing rainforest destruction as well as amphibian biology. In the home the whole family will not only appreciate the frogs but will find the exotic tropical plants equally interesting.
19. Their entire life cycle can be viewed inside the vivarium.
Their ease of care and bold personalities allow you to view the entire fascinating life cyle right within the walls of the tank.
20. They are a healthy addiction!
Keeping dart frogs doesn't cause cancer or liver disease but you may need the help of a 12-step program if you ever need to part with your collection!!
By Karl Gruber
22 April 2015
Some poison dart frogs are so lethal, native hunters once used them to make, well, poison darts. Why are these beautiful animals so deadly?
In the midst of the hot and humid Colombian rainforest a nearly naked man walks silently among the trees, looking for his next meal. Spotting a distracted monkey, the hunter readies his blowgun and darts. One shot will be enough. According to a first-hand account from 1825, the dart is "certain death to man or animal wounded by it". That's because it is laced with poison.
Hunters from Colombia's Embera tribe regularly hunted birds, monkeys and other small animals using poison darts. The poison came from bright yellow frogs just a few centimetres long.
A single "golden poison frog" harbours enough poison to kill 10 grown men, making these frogs perhaps the most poisonous animals alive. They are one of many species of toxic frogs, which are known as poison dart frogs. They are all small: the largest are no more than 6cm long, and some are just 1.5 cm. How did these tiny, beautiful creatures become so poisonous, and why?
- Poison dart frogs are the most poisonous animals alive :
A golden poison frog (Phyllobates terribilis) (Credit: Dirk Ercken/Alamy)
Millions of animals produce toxic substances, but most of them are not poisonous. To be poisonous, an animal must be toxic to eat, or in extreme cases, even to lick. For instance, venomous snakes like the lethal inland taipan are not poisonous. They are only dangerous if they bite you, injecting their venom into your bloodstream.
(( Only a handful of species pose a risk to humans ))
The golden poison frog has no such limitations. It keeps its poison in glands beneath its skin, so any reckless human taking a bite would be in trouble immediately.
Other poison dart frogs are far less toxic than the golden poison frog, and only a handful of species pose a risk to humans.
Obtaining the poison for use on darts was a gruesome process, according to an account published in 1978. Local people would "catch the frogs in the woods, and confine them in a hollow cane." When they needed poison, they would take a frog and "pass a pointed piece of wood down his throat, and out at one of his legs."
Unsurprisingly the frog would become agitated, and begin sweating poison, "especially on the back, which becomes covered with white froth". The people dipped their arrows in this poisonous liquid, which remained potent for a year.
The poison is called batrachotoxin. It causes paralysis and death when it enters the bloodstream, even in minuscule amounts.
Anthony's poison arrow frog (Epipedobates anthonyi) (Credit: blickwinkel/Alamy)
Batrachotoxin belongs to a large group of chemicals known as alkaloids, which are found in many animals and plants. With the exception of a few non-poisonous species, all other poison dart frogs also use alkaloid poisons.
For example, Anthony's poison arrow frog lives in the forests of Peru and Ecuador. It is dark red or brown, with yellow stripes. It harbours two powerful alkaloids called epibatidine and phantasmidine.
According to a study published in 1998, even tiny amounts of epibatidine can cause severe damage to an animal's brain and muscles. This can lead to respiratory paralysis, high blood pressure, seizures and death.
What's more, it's not just adult frogs that are poisonous. Baby frogs are too.
A strawberry poison dart frog (Oophaga pumilio) (Credit: Visuals Unlimited/NPL)
In a 2014 study, Ralph Saporito of John Carroll University in University Heights, Ohio, found that mother frogs supply their tiny tadpoles with poison. The tadpoles absorb the toxin and become poisonous themselves.
Frogs feed their tadpoles on their own unfertilised eggs, and it's this food source that supplies the poison. "Mom is able to provide them a defence by placing alkaloids in the eggs," says Saporito.
This has the useful effect of scaring off predators that might otherwise eat the tadpoles. "It appears that the alkaloids in tadpoles are sufficient in deterring some potential arthropod predators such as hungry dragonflies," says Saporito. They might also protect against infection.
Deterring predators seems to be a major use for the poisons in at least some species.
That might not sound like much of a defence. After all, in theory the frog has still had a chunk bitten out of it, which won't do it any good. But in practice predator attacks hardly ever go that far, thanks to the frogs' other weapon: colour.
A marbled poison frog (Epipedobates boulengeri) (Credit: Bert Willaert/NPL)
Poison dart frogs are brightly coloured, with a wide range of patterns. Their colours include white, black, yellow, orange, red, green, blue and everything in between, says Kyle Summers of East Carolina University in Greenville, who has studied them for 30 years.
In nature, bright colours are often a warning sign. Many animals are dishonest: they boast bright colours yet pose no danger. However, most poison dart frogs are not bluffing. Their colours send a clear and honest signal that would-be predators should avoid them, says Summers
In a study published in 2001, Summers showed that the most conspicuous frogs, those bearing the brightest colours, were also the most poisonous. His team rated how conspicuous the frogs were against a typical background, and found that this correlated strongly with how toxic their poison was.
Strawberry poison dart frogs are scarily colourful (Credit: Edwin Giesbergs/NPL)
The predators may well have got the message, according to a 2012 study by Molly Cummings of the University of Texas at Austin.
((The brighter frogs were more toxic))
Her team collected strawberry poison dart frogs from western Panama, and measured how toxic the frogs' skin chemicals were. She also measured their colours precisely, using an instrument called a spectrophotometer, and determined how easily predatory birds could detect them.
As before, the brighter frogs were more toxic, and Cummings' calculations suggested they were also more conspicuous to the birds. "This relationship informs potential predators, such as birds, just how much of a punch these frogs deliver," says Cummings. Back in 2006, she also showed that predatory birds quickly learn to avoid the colourful frogs.
Clearly, being poisonous is advantageous to the frogs. The question is, how did they become so lethal?
Poison dart frogs evolved in rainforests millions of years ago (Credit: Steve Bly/Alamy)
Poison dart frogs all belong to the same family of frogs, the dendrobatids.
(( It seems the frogs are descended from something like a true toad ))
The group was born some 40-45 million years ago, somewhere in the forests of northern South America, says Juan Santos of the University of British Columbia in Vancouver, Canada. "During this time most of South America was warm and covered with tropical forest, and the Andes were not higher than 2500m above sea level."
The poison dart frogs' ancestors were not poisonous, and nor were they colourful or small, says Santos.
In a study published in 2003, Santos attempted to trace the ancestry of the frogs by examining their genes. The results are not definitive, but it seems the frogs are descended from something like a true toad, complete with warts.
Poison dart frogs may be descended from toads (Credit: Pete Oxford/NPL)
This common ancestor was probably "diurnal", meaning it was active during the day, says Santos. Most of the 300 known poison dart frogs are diurnal, whereas most other frogs, including all of the poison dart frogs' likely ancestors, are active at night. "We expect that diurnality is derived from a nocturnal ancestor," says Santos.
In that respect, modern poison dart frogs are similar to their last common ancestor. But in another respect, the ancestor was completely different: it wasn't poisonous at all.
"The origins of toxicity are more complicated," says Santos. The poison evolved some time after the origin of the poison dart frog lineage, according to Santos' data, and different groups evolved it at different times.
Why are golden poison frogs so deadly? (Credit: blickwinkel/Alamy)
"There are between 4 and 5 independent origins," says Santos. The first was around 30 million years ago, while the most recent was just 2.5 million years ago.
(( The ancestors of poison dart frogs may have started eating toxic ants ))
The key to the story is that the frogs don't make the poisons themselves. They get them from animals like ants that they eat. "These prey items are the main source of poison frogs' toxins," says Santos.
The ancestors of poison dart frogs may have started eating toxic ants by sheer chance, and begun harbouring the poisons in their bodies. Some of the key chemicals on the frogs' skin have been traced to ants, beetles and millipedes.
This seems to fit with Santos's claim that the frogs acquired the ability to make poison on several different occasions. "Most of these origins are associated with locations that were, or are, covered with dense tropical rainforest with enough diversity of ants and mites," says Santos.
Rainforests are teeming with toxic insects (Credit: Robert Harding World Imagery/Alamy)
These early poison dart frogs had a big problem: not being poisoned themselves. It is not yet clear how they managed to withstand and retain the poison, says Summers.
One idea is that they had a high metabolic rate, meaning their bodies could process nutrients and other chemicals quickly. "The high metabolic rate could have been crucial in allowing members of this lineage to withstand and process the toxins," says Summers. In effect, the frogs were "pre-adapted".
Rainforests are dangerous places, with many predators out to eat a tasty frog
That may explain how the frogs became so poisonous, but why did they do it? Rainforests are dangerous places, with many predators out to eat a tasty frog. But many similarly small animals have found less extreme ways to survive, such as camouflaging themselves.
There may have been something specific about the poison dart frogs' ancestors that made them predisposed to defend themselves using poison. Or it could be largely down to luck, says Summers.
Whatever the truth, nowadays the frogs are not the only ones benefiting from their poisons. Neuroscientists are studying the toxins in the hope of designing new drugs.
A Brazil-nut poison frog (Adelphobates castaneoticus) (Credit: Visuals Unlimited/NPL)
"It's not that the compounds cause toxic effects that is of interest here," says Richard Fitch of Indiana State University in Terre Haute. "It's the way they do it that is useful to the scientist and physician."
There is precedent for this. Some alkaloids turn out to have anticancer activity, while others serve as stimulants similar to caffeine.
((You wouldn't give phantasmidine to someone who's in pain ))
Epibatidine and phantasmidine are prime examples. They may be lethal, but they also both numb pain. They act on the same receptors on our brain cells that respond to nicotine.
You wouldn't give phantasmidine to someone who's in pain, but by studying its structure and chemistry it may be possible to design better pain-killing drugs. Fitch and his team are developing upgraded versions of phantasmidine that are similar enough to still ease pain, but without the toxicity.
"If we can cut the key just right, we get the activity we want," says Fitch. "That's perhaps a tall order, as we don't quite know what the lock looks like, but we have a key and that's a start."
This new use for poison dart frogs may well have replaced their previous one. The practice of using them to make poison darts was in decline as early as the 1970s. It's difficult to tell if the Embera people still do it, says Summers, because the area where they live is "remote and very dangerous because of guerilla activity".
(( The skin of strawberry poison dart frogs can fend off some bacteria and fungi ))
If no one is making poison darts anymore, that's good news for the frogs: at least they aren't being pierced with sticks. But like many amphibians, poison dart frogs are vulnerable to extinction, as the forests they live in have been hacked back. They may also be at risk from a fungus called chytridiomycosis, which kills amphibians by infecting their skin.
Might their poisons offer them any protection? The skin of strawberry poison dart frogs can fend off some bacteria and fungi, according to a study published in January 2015. But that doesn't necessarily mean it can fight off the chytrid fungus.
"At this point, we do not know if the alkaloids in dart poison frogs offer them any protection from chytrid," says Saporito. "This is something we are beginning to actively study in my lab."
It seems unlikely that the poisons will be enough to save the frogs, but they might at least buy some time.
Updated 23 April 2015: This article has been amended since its initial publication to clarify some of the statements made.
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