Pygmies of Mount Gorongosa

December 10, 2012

“You should not be there at night,” said Tonga, “it is not recommended.”

Since doing things that are not recommended is what I like to do, I dully noted my assistant’s objection, waved him goodbye, and began a hike towards the top of Mount Gorongosa. I was in Mozambique, a member of a group of biologists working on a survey of the Gorongosa National Park. The mountain had only recently become a part of the park, and its mysterious, unknown katydids beckoned me ever since I had arrived in the country a few weeks earlier.

But katydids, being cryptic and all, are not easy to find, and the only sure way to get them is to quietly follow their calls at night. This activity benefits from the lack of company, hence my decision to spend a few days on the mountain by myself.

 

As soon as I got to the rainforest that envelops the mountain below the peak, I pitched my tent and set out to see what was out there. By then it was already dark and insects were beginning to sing. I scanned the vegetation with a headlamp and immediately noticed a tiny creature hugging a branch, an animal whose shape seemed both unexpected, and yet oddly familiar. It took my brain a second to pull together disparate threads of superficial knowledge, and then… Sweet Merciful Jeebus, this is the Gorongosa Pygmy Chameleon!

I had read about this nearly mythical lizard, discovered only in 1971 and seen since by only a handful of people, and never expected to chance upon it during the first few minutes of my foraging. The Gorongosa Pygmy Chameleon (Rhampholeon gorongosae) is a member of a group (Brookesiinae) that has radiated extensively in Madagascar, but has only a few members in Africa. Unlike the “non-pygmy” chameleons (Chamaeleoninae), which live high on trees and bushes, pygmy chameleons spend most of their life in the leaf litter, and climb branches only at night to avoid being eaten by shrews and other nocturnal predators. And since few night predators are equipped with good color vision, at night they shrink their color-producing chromatophores in the skin, and turn ghostly pale. This of course makes them easy to spot by somebody carrying a powerful flashlight, and soon I started noticing dozens of them, sleeping on trees and bushes all around me. One was perched about three feet from my tent, and I decided to get up early to see its descent and the beginning of its daily routine. I was hoping to photograph it throughout the day as it hunted insects in the leaf litter. Alas, although I got up just before dawn, the chameleon was already gone. I spent the entire day looking for these lizards, and found none, but right before sunset the chameleon was back on its perch in exactly the same spot as before.

The following morning I got up even earlier, just in time to see my chameleon make it slowly to the forest floor. It was a female, and I spent several hours tracking her every move, watching and photographing her as she fed on termites and other small insects. Every now and then I threw a tiny grasshopper in her direction, and almost invariably she caught it with her incredibly long tongue. At some point I took my eyes off her for a few minutes, and she vanished.

 

Crypsis is these animals’ only defense, but they managed to turn it into a form of art. Not only do they resemble a piece of wood but, like all chameleons, they are incredibly good at changing their body color and pattern to match the substrate on which they are sitting or walking. Although most of the time the Gorongosa chameleons display various shades of brown to match dead leaves on the forest floor, if they find themselves climbing a vine or another live plant, they turn green. It is rather entertaining to watch them climb things, which they do very skillfully, if very slowly, despite the lack of a prehensile tail that defines their larger cousins.

Brown Leaf Chameleon (Brookesia superciliaris) from Madagascar, although Yoda Chameleon might be a more apt name for this species. 

 

My encounter on Mount Gorongosa was not the first time that I met pygmy chameleons. Nearly a decade earlier I spent some time in Madagascar, and there I saw several species of the genus Brookesia. They were similar in shapes and sizes to the Gorongosa chameleons, and also lacked the prehensile tail, but these features turn out to be the result of convergent evolution, rather than true close relatedness of African and Malagasy species. They also exhibited one quite unexpected behavior that I did not see in the African species. Just like their cousins from Mount Gorongosa, brookesias drop to the ground and remain motionless until the danger passes. But if it does not, such as when I picked one of the lizards with my hand, they suddenly turn into a really pissed off, loudly buzzing bee! Or at least that’s what my sympathetic nervous system told me, forcing my hand to drop the animal almost as soon as I touched it, even though my brain knew that it was a bluff, and that I was still holding a small, harmless lizard. Such buzzing defensive behavior has been seen in a few species of chameleons, but its mechanism is poorly understood.

The Mount Gorongosa Pygmy Chameleon may be smaller than your pinky finger, but it is a magnificent symbol of Mt. Gorongosa’s unique ecosystem, and it is not alone. During the few nights that I spent on the mountain, in those moments when I wasn’t giggling with delight at the sight of the most adorable lizard on the planet, I found several new to science species of katydids. It is quite likely that, like the chameleon, they are endemic to Gorongosa, and I absolutely must go back to learn more about them. Even if it is not recommended.

 

By Piotr Naskrecki

 

Read more on his blog The Smaller Majority

Category: 
Bush Diaries