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Little Brown Jumper

Posted on Jan 16, 2015

A most amazing encounter in a small, drab package…

I am a fortunate man…I’ve traveled to all sorts of exotic locales and am lucky enough to have encountered some pretty spectacular wildlife in the process. Photographs of some of these wonderful frogs, birds, snakes and other treasures have graced these posts in the past. This time around I would like to share with you something tiny and drab instead, but something that made me profoundly happy to encounter!

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During a recent trip to Costa Rica I had a brief opportunity to detour from my already scheduled destinations in hopes of finding something I had wanted to see for years…one of the last survivors of its kind, the Lowland Rain Frog (Craugastor ranoides). This brown, nondescript frog of rocky streams once ranged widely throughout Nicaragua, Costa Rica and adjacent Panama and sometime in the late 1980s or early 1990s they were all gone. People started noticing the absence of charismatic, brightly colored species, but nobody even suspected the demise of these ‘little brown jobbies’ until it was too late. They just became collateral damage in an outbreak of the deadly fungus Batrachochytridium dendrobatidis, or Bd. We now know that this Bd wiped out significant numbers of amphibian populations throughout the world and continuous to do so in many areas.

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Almost two decades passed in which concerted efforts were launched to find relict populations of species gone missing altogether. At the same time elaborate ex-situ captive breeding programs were developed for a select few frogs to safeguard their continued survival in captivity at least, for lack of other alternatives. Recently, the former efforts are starting to pay off…little by little some of the species that had not been seen for many years and feared to be gone completely were encountered again in very small numbers in remote areas. One small population at a time, several of these resilient little creatures are rebounding from a catastrophic event!

The Lowland Rain Frog is one of those survivors – once common in suitable habitat throughout its range it is now only found in a small isolated watershed in Guanacaste, the hottest and driest part of Costa Rica. The Bd fungus is most virulent in relatively cool and wet climates and it hit hardest at middle and high elevations where frogs also thrive. The seasonally very dry climate in Guanacaste has so far kept the fungus at bay and the isolated nature of the watershed these frogs are found in provides a comfortable buffer.

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Ignoring almost every stipulation in my little car’s rental contract I drove out on barely passable dirt roads and forged several streams to reach my destination, a remote section of Santa Rosa National Park. This famous national park protects the largest area of tropical dry forest in the Americas – a habitat type that has suffered for centuries from uncontrolled slash and burn agriculture, leaving many of its unique species currently at risk.

Santa Rosa habitat DSC_2999
The habitat appears inhospitable – everything that grows there seems thorny, spiny, or otherwise painful. Even the wildlife appears to have an attitude as large Spiny-tailed Iguanas (Ctenosaura similis), ferocious-looking like mini-dragons, crash loudly through underbrush.

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Once I spotted a small rocky stream in this arid scrub land, I knew I had arrived – this looked like the place to be! Lowland Rain Frogs are primarily nocturnal and they hide deep under large boulders during the day. Unfortunately, I found myself there by mid-day with little time to spare. To top things off, I was limping around in an air cast, suffering from a badly sprained ankle. Not exactly the ideal conditions to find elusive rare frogs! From previous field work in El Salvador where I had discovered a related species I knew that these frogs sometimes hide in the leaf packs that collect between rocks, so I started looking there. After about an hour of intensive searching below rocks and in leaf packs, a tiny brown froglet suddenly launched itself from underneath a rock, instantly followed by a lightning fast young Speckled Racer (Drymobius margaritiferus) a snake that feeds primarily on frogs.

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Momentarily startled by the sudden movements I somehow managed to catch both the little frog and the snake, while simultaneously slipping and twisting my bad ankle in an excruciating way. After gritting my teeth for about ten minutes I managed to get the little jellybean-sized frog onto a rock to photograph it with my macro lens. This frog was so tiny and non-descript that I could not even see its diagnostic features with the naked eye, but enlargement of the image on my camera showed that this was a recently metamorphed Lowland Rain Frog!

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The realization that I was looking at this smallest of creatures – a survivor that had beaten many odds up until then (and I may have inadvertently saved it from becoming snake lunch!) was a most powerful experience. Like I said before – I am a fortunate man to experience these amazing creatures, but sometimes the most meaningful encounters come in very small, drab packages…

I took a few pictures of the little guy and let it go on its way with the happy knowledge that not only do the Lowland Rain Frogs still survive here, they are actually breeding successfully! The snake I photographed too and let it go a little ways away from the frog….silly, I know, but I couldn’t help but think that I did not want the odds stacked against these incredible survivors even more then they are already.

In two weeks I will be heading to Panama to continue our research on endangered harlequin frogs and other imperiled amphibians there. Hopefully I come back from that expedition with more great news then. You’ll read about it here!

Twan Leenders
RTPI President