The Mexican Tree Frog is among Costa Rica’s biggest frogs. It is somewhat similar in appearance to the Masked Tree Frog, however the Mexican is bigger; its overall color is brown instead of green, and does not show such a definite dark brown patch behind the eye. The eyes are very similar between both species. It does occur in the Guanacaste province, from which the Masked is absent, however it is not found on the Pacific south from the Tarcoles river. They are nocturnal and arboreal like most tree frogs.
The Smooth-skinned Toad (or Leaf-Litter Toad as it is called sometimes) is a species of true toad that bears a dead-leaf pattern on its skin, concealing it from most predators when they lie motionless in tree bark or the ground. Furthermore, their lifestyle is nocturnal, so during the day they don’t move much, unless spooked. They rely on that camouflage to be safe, even around streams, where their dull colors can match the colors of some rocks. They are small, around the size of a female Green and Black Poison Dart Frog, but their overall coloration is a dull brown with orange and dark blue patches, making them incospicuous against the brown layer of leaf litter.
The Strawberry Poison Dart Frog, along the Green and Black Poison Dart Frog, are one of the common diurnal species that can be found in tropical rain forests in Costa Rica, particularly at the Caribbean side. It is common to go hiking and see these bright red and blue frogs suddenly jump from the trail. Due to the color of their legs, they are also called the “Blue Jeans”, although in Costa Rica some individuals are found that have red legs and arms, and in other countries like Panama there are many more morphs with entirely different color patterns. Regardless of the specific colors, they are very conspicuous and do not camouflage well on the leaf litter that tends to be brown to black. They are tiny when compared with many Tree Frogs.
As with the Green and Black Poison Dart Frog, caution must be taken not to touch these frogs when photographing them with macro lenses, as their skin is poisonous and any contact of their secretions with our eyes, nose or mouth can cause much discomfort. While handling them does not produce any symptons, if one is careless, then it is possible to touch one´s sensible organs with the hands and experience significant effects, up to partial blindness.
The Masked Tree Frog is a nocturnal, arboreal species that can be found on the lowlands and foothills of both the pacific and caribbean sides of Costa Rica, although it does not occur on the dry plains of Guanacaste. Its color is variable, however the dark brown patch behind the eye is unmistakable. Their color ranges from entirely tan to entirely green, with intermediate, contrasty patterns in between. When most of their body is tan, it can look very similar to the Cross-banded Tree Frog, however the Cross-banded never has a mask. Their vocal sacs are bilobed, which essentially means that it looks like two vocal sacs, one at each side of the throat.
I have an story of a time I visited Mirador El Pizote, in Boca Tapada, San Carlos. One of these frogs had entered the cabin where I stayed, possibly during the night. I was going for a bath and found the frog resting on the bathroom. After trying a few pictures (that did not work out very well), I tried to grab it to put it outside, but it jumped rapidly and dissappeared. Since I could not follow its movement, I was never sure whether it went outside or stayed inside.
The Green and Black Poison Dart Frog is one of the species in this family that occurs in Costa Rica, along with the Strawberry Poison Dart Frog and other species, although this species is bigger than the Strawberry. Poison Dart Frogs are diurnal, so it is relatively common to flush them from the floor litter during hiking trips through forested areas. Their contrasting body color is an adaptation meant to signal their poisonous skin to potential predators, helping these frogs escape from danger. Poison Dart Frogs are known because of their ability to withstand ant venom and convert it into their own which means the older the frog, the more poisonous it becomes. Some of these species were used by aboriginal people in South America to kill monkeys and other prey, by rubbing their skin to the arrows that they shoot.
It is normal to see Poison Dart Frogs resting on the leaves of bromeliads, where they usually deposit their larvae, which will develop inside a water pool in the base of a bromeliad leaf. They are more conspicuous when seen on leaf litter, which usually turns brown as the vegetation decays. Also poisonous species like this one are more active during the day. The two times I have had the opportunity to photograph this species, I was careful to keep my distance, as they jumped around quickly and could touch me at any moment. While being touched generally won´t produce any reaction, being careless afterwards and bringing the hands to touch the eyes or the nose after having grabbed one of these can produce significant effects, up to partial blindness.
The Chiriqui Robber Frog is a rare nocturnal, arboreal inhabitant of humid lowland and montane forests in tropical countries, namely Costa Rica, Panama and Colombia. Their color and pattern is highly variable and cryptic, but overall includes varying shades and patterns of dark colors like brown and black, which helps them to camouflage easily in the forest. It lacks webbing on the hands and feet, but shows greatly enlarged disks on the toes and fingers. The best field mark to identify this species is the black reticulum on the brown eye.