Poison-Dart_Frogs

Poison-dart Frogs
This group of frogs owe their name to the fact that several species of South American Dendrobatids have been used by Amerindians to coat the tips of their blow darts and or arrows, with the toxic secretions from these frog’s skin. Have a blow dart, or an arrow? Do you need to make it more lethal, or give it more stopping power? One answer was to find a special brightly colored frog, and to either rub the arrow tips on its back, or to cook, or sweat the poison out of it, and capture the toxic liquids that dripped off. Some frogs are so toxic, that you should not even handle them with uncovered hands. This is not so much the case with the 8 Dendrobatid that occur in Costa Rica. However the uses and treatments of such amazing creatures underscores their evolutionary path.

These are frogs that are active during the day, they are for the most part, brilliantly colored or at least adorned with bold stripes. This to would-be frog-eaters is should be an obvious message “eat me, and you will be sick, or worst than sick”

Polar opposite to camouflage, this is aposematic coloration, or warning coloration, as is the yellow and black of bees, and the bright banding on a coral snake. The toxic secretions of these frogs is dependent upon diet. Captive raised poison-dart frogs which are not fed ants,do not develop the toxins necessary to back up the threat,which has led to their niche, that of a slow diurnal insectivorous amphibean.–one that can look pretty, and sing proudly in the light of day, or at least where some of it might penetrate the canopy.

 

 

Dendrobates pumilio the Strawberry poison-dart frog, or the Blue jeans poison-dart frog is a fairly common small frog of the forest floor, and lower level of the lowland Caribbean Rainforest. The sound which should load with this page, is insect-like, and while the piece provided here is just a snippet, it is not uncommon to hear several males singing from low perches, each with a song like this however lasting upwards of a minute.

Links: Dendrobatidae (Poison-dart frogs)
http://en.wikipedia.org/wiki/Poison_dart_frog
http://animaldiversity.ummz.umich.edu/site/accounts/information/Dendrobatidae.html
http://amphibiaweb.org/lists/Dendrobatidae.shtml
http://www.tolweb.org/Dendrobatidae/16956
http://www.livingunderworld.org/anura/database/dendrobatidae/dendrobates/auratus/

(Phyllobates lugubris)–above, is the striped poison dart frog of the Caribbean lowlands and foothills. The trilled call of this species is heard low near the forest floor. This individual was heard, photographed and sound recorded at OTS Finca La Selva. The voice of (P. lugubris) has a plaintive ringing quality.

(Phyllobates vittats)–left, is the striped poison-dart frog of the Pacific lowland rainforest in Costa Rica. The vocalizations of frogs are used to advertise the presence of a male. Male frogs want to both attract a mate, and protect a territory, or a space within their habitat.

The male (P. vittatus) to the left has actually been drawn to the top of this rotting log in Corcovado N.P. by playing back a recording of its own song. Male poison-dart frogs are very territorial, and aggressive towards tresspassers.

If you are standing and playing a recording in their territory, you may end up with poison-dart frog on the toes of your rubber boots.

The original photo included part of the tape recording equipment. The recorder was being played on the log–and “presto-dendro-batid”

(Dendrobates granuliferus) -right, photgraphed in Corcovado National Park, Costa Rica, lowlands near the Sirena Field Station. The Pacific rainforest counterpart to the much better known, and more often photographed (Dendrobates pumilio) of the Caribbean versant.

(Dendrobates auratus)-left, the black and green poison-dart frog, is found on the southern Pacific rainforest of Costa Rica. Personally I’ve seen and photographed very few from near the Sirena Field Station in Corcovado N.P.

Though the individual photographed to the left is from a captive individual. This does seem to be one of the more common captive bred species.

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Tree_Frogs

Tree Frogs
Tree frogs, or Leaf frogs–the family Hylidae, represent a large family of more than 800 species worldwide. Costa Rica’s 43 species of tree frogs accounts for one third of the republic’s frogs.

Their tree and leaf-climbing adaptations include large adhesive toe pads, long limbs, binocular vision, and impressive jumping ability. Some species spend their entire lives in the canopy. Others visit ponds and streams to breed, while some are found predominently on the forest floor. The most famous hylid in Costa Rica is no doubt the Red-eyed tree frog (Agalychnis callidryas) –see image on home page.

 

 

Tree frogs such as the (Smilisca baudinii) pictured above have wide, suction cup-like toe pads which aid them in climbling and holding on to leaf and limb surfaces (they do pretty well on glass as well). (Smilisca baudinii) has one of my all time favorite calls, a loud rapid series of deep honks.The quality of the sound has is like the honking from a clown’s horn.

Links: Tree Frogs

http://www.amphibiaweb.org/lists/Hylidae.shtml
http://www.tolweb.org/Hylidae
http://www.livingunderworld.org/anura/database/hylidae/
http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylidae.html

Leptodactylids

Leptodactylid Frogs
Leptodactylid frogs, sometimes refered to as Neotropical frogs, and rain frogs, are the frog family with the most representative species in Costa Rica. The 46 species listed account for a third of Costa Rica’s anuran diversity.

Many of these species are very cryptically colored, blending masterfully into the forest litter layer. Quite a few of them are refered to as litter frogs. These are many a little brown job, hopping toad-like, and hiding under the fallen and decaying leaves. Others as the Smoky jungle frog to the left, complete with mosquito, are more formidable. In the rain forests of Costa Rica there is not a bigger frog (though there is a bigger toad). This frog is both a sit and wait predator, which will station itself patiently until it’s prey gets just close enough, as well as an active predator, one that will approach a chorus of vocalizing frogs, and close in to make the kill. There was always something very cool about these frogs, I would sometimes think of them as the jaguar, of the frog world. The picture above is of a frog near it’s burrow.

True_Frogs

This is frog filler…..

True Frogs seems perhaps the worst frog name of all? While the family Ranidae occurs on several continents and includes some of the best known and most recognizeable species extant, they are frogs, and in this authors estimation, no more a frog, than another frog in a world filled with frogs–so maybe something like Ranids would be better 🙂

But a frog is a frog, and by any other name its skin is smooth, eyes large and buldging, and the sound of its croaking is sweet.

crf_families

Costa Rican Frog and Toad Families

Herpetologist have placed the roughly 133 species of frogs and toads found within the Republic of Costa Rica into 8 groups or families.

These are the burrowing toads, toads, glass frogs, poison-dart frogs, tree frogs, leptodactylid frogs, narrow-mouthed frogs, and true frogs.

This website will attempt to provide some representative examples of each family, and to provide links to additional resources.

The frog above belongs to the family Leptodactylidae. This is family which includes the genus eleutherodactylus-and a variety of frogs sometimes referred to as rain frogs has the most species of all CR anuran families with 46.
Costa Rican Frog and Toad Families # of species
Rhynophrynidae (Mexican burrowing toads) 1
Bufonidae (Toads) 14
Centrolenidae (Glass frogs) 13
Dendrobatidae (Poison-dart frogs) 8
Hylidae (Tree Frogs) 43
Leptopdactylidae (Leptodactylid frogs) 46
Microhylidae (Narrow-mouthed frogs) 3
Ranidae (True frogs) 5
Total
133

Microhylids

Microhylids
Microhylids or Narrow-mouthed toads are represented by three species in Costa Rica.

They are probably best known by their loud buzzing vocalizations, to me reminiscent of a motor running at a high RPM, or a propeller plane moving by. Following periods of heavy rains microhylids will come to ponds and puddles to breed, to lay eggs.

Frogs as a group try to avoid ponds with fish. These are creatures which will eat the eggs young. While bodies of water will offer some advantage to eggs and tadpoles, they do not ensure safety to the adults which congregate at them and advertise their presence.

(Gastrophryne pictiventris) calls from the water surface, the frog to the left is holding on to a pond side leaf, while calling outward. Perhaps as a defensive measure, the calls of one male, run into and overlap others. Making it difficult to pinpoint the individual vocalist.