Lessons from Travels: Tropical Herp Diversity

by Carl Strang

I have made two trips to the Central American tropics, a month-long graduate course in tropical ecology that explored Panama in 1975, and a briefer vacation trip to Belize and Guatemala in 1989. The sheer diversity of life forms provides the most striking contrast to northeast Illinois, and this is nowhere more apparent than in the reptiles and amphibians, or herps. Most of the species I could not name, but the sampling of photos will give some sense of this variety.

This forest floor toad is one example. Striking in its angular lines and the white mark on its lip, but I saw only one of these and never learned its name.

We have numbers of frogs, toads, salamanders, snakes, lizards and turtle species whose variety could be summed up with the word “several.” In the tropics, “overwhelming” fits better. The needs of these animals for warmth and moisture are well met down there, and the imagination soars with what Illinois was like in periods of its geological history when the climate was more like that of today’s Central America. Such observations during the Panama class also set me up for some of what I was to learn later in my study of terrestrial turtles in Pennsylvania, but that is a story for a later time.

One of the students in the Panama class was a herpetologist, and one day he brought a fer-de-lance into our Limbo Hunt Club camp to show us.

The fer-de-lance was small, but venomous and needing respect. You can bet we were watching our step as we walked the forest trails.

We encountered few snakes, however. One of my fondest memories was the opportunity to hold a sea snake.

This was a captive, in a study tank at the Smithsonian Tropical Research Institute. If memory serves, we were told it was from Southeast Asia. Highly poisonous, but very placid, it was amazing in its sideways-flattened body and its scales, which were like tiny bricks placed side by side rather than overlapping as in most snakes.

We have a few species of snakes that like the water, too, mainly associated with our rivers, but lacking the extreme anatomical specialization evident in the sea snake.

Most of the reptiles we encountered were lizards.

My notes say this skink is in genus Mabuya.

And here is another, nameless lizard, on the alert for insects.

Above all, however, the herps we found were frogs and toads. Some were hylids, like our spring peeper.

The red-eyed frog is a relatively famous example.

Another beautifully marked hylid.

This one has a color pattern reminiscent of our wood frog, which belongs to a different family.

There were unfamiliar behaviors, as well, like the protective bubble nests created by the túngara frog.

We went out at night to see these frogs in action.

I spent some time inventorying the color variations in Bufo typhonius (it apparently has no generally accepted English name), a forest floor toad species with various leaf mimicry patterns.

At one extreme were some with uniform coloration.

Others had complex patterns, this one going so far as to produce a midrib.

This by no means exhausts the subject of tropical species diversity, and I will have more to share on this subject.

(Note: I was saddened to learn recently that Panama’s frogs are in peril. A fungal disease has been spreading through the isthmus, and is threatening many of the country’s 200 species with extinction.)

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