A Sumaco Casque-head (Hemiphractus probosciedus)

Night hikes have proven to be the thing that I probably most enjoy out of all of the activities I get to perform through my work. There is something that draws me in about hitting the trails after dark. Night hikes are a giant Easter egg hunt in that you have no idea what you will find but the possibilities are virtually endless. And I have had a few unusual experiences on these nocturnal forays. One evening in the upper Amazon Basin, in Peru, is especially memorable. We hiked in a few miles from the river along a trail. A bank of fog had crept through the forest in the meantime, concealing the area where our trail lay. We walked right into it. If you haven’t experienced an Amazonian fog, it is something you never forget. It is a strange feeling to know that there are hundreds of trees surrounding you yet you are unable to see any except the ones within reach. The one thing that is accomplished while the fog is there, everything is damp without there having been a heavy rain. This is a key feature because it tends to bring small creatures out of their hiding places. This forest was a special place in my youth. It hadn’t ever been cut. Massive trees lined the trails with trunks that took some effort to walk around in their giant diameters. The feel of the place was electric. The invertebrate community there was special – species that one finds only when working in old growth forest. This translates to different sounds – calls from species you don’t often hear elsewhere in younger forest stands. That night had delivered another set of strange sounds as well – a jaguar was roaring at times and grunting at others…for all we knew, it could have been breeding time for the big cat with the variety of different sounds being produced. I loved this forest stand. I had visited it many times and we always found interesting wildlife – this evening wasn’t going to let me down either. With the foliage wet from the fog, dozens of “rain frogs” (Pristimantis sp.) were calling and sitting out in the open on low hanging leaves. These small frogs are important food items for quite a few other animals, including a very special group of frog-eating frogs, the Casque-headed Frogs (Hemiphractus sp.). There are no fewer than three species of Casque- headed frogs in the Loreto (Peru) area, probably more, but they are always special encounters. I had seen quite a few in the forest stand and sure enough, out on a large leaf about a meter off of the forest floor, one was staring back at me in the beam of my flashlight. I had learned over the years that these frogs will bite when handled and the bite was always a lot stronger than expected. If threatened, these frogs “gape,” which involves opening their large mouths toward the threat in a menacing manner. In their bag of tricks is an escape tactic. When things are looking bad with regard to encountering a potential predator, the frogs will jump from their positions and fall to the forest floor below where they remain motionless and difficult to discern from the leaves around them. Also included in the diets of these frogs are small lizards. They seem to have a fondness for anoles (Anolis/Norops sp.) in particular. The body design of the frogs is generally cryptic. In this species, the Sumaco Casque-head (Hemiphractus proboscideus) has a long, fleshy finger of tissue extends from their rostrum to form a “nose” of sorts. They also have folds of tissue extending outward from their ankles called “calcars” ...and small pointed flaps from the tops of their eye lids. These extra additions to the body plan of a frog help to break up the predictable outline of a frog’s body. They are believed to be cryptic characters, things helping them elude the searches of visually oriented predators. This is the concept of the "search image." The broad head of these frogs opens into a spacious mouth which they use to take small vertebrate prey items. Never common in any particular area, I had several forest stands in my youth where we could find one or two of these frogs across an evening of night hiking. Every one of those stands no longer has any vegetation at all. Habitat loss in the Amazon is a real thing. Perhaps the most dangerous character of rainforest loss is that it is out of sight and mind of most of the world’s human population. Folks hear of the losses but few see it up close and personal. These forests were like old friends and I have been deeply impacted as each one of these special places was cut down and plowed under. If humans are going to have much of a future on this planet, we can’t allow things like this to continue. We lose biodiversity at our own peril. Please consider donating to an environmental cause. You'll be giving everyone the gift of environment.