Uganda Travel News

Every species has basic needs food, water, security, social support, opportunities for reproduction. Food and water come first and mountain gorilla tracking derive both from the rich plant life of the Virungas. The recent loss of 40 percent of the forest habitat of the Parc des Volcans raised deadly serious questions about the long term viability of the remaining 260 Virunga gorillas. Recovery to the population levels of four hundred to five hundred gorillas recorded by George Schaller seemed out of the question.

Almost twenty years later, Schaller’s 1960 study of the mountain gorilla remained the only significant source of information on gorilla feeding ecology. In addition to his comprehensive analysis of their behavior and social organization, Schaller documented the gorillas’ use of diverse habitats on Mt.Mikeno in the Congolese sector of the Virungas. He also introduced the use of direct observation to record the foods consumed by gorillas. This was a great improvement on the indirect methods of dung and stomach content analysis that were considered the only feasible way to obtain information about wild animal diets at that time. Yet despite Schaller’s promethean efforts, there was much more that we needed to know about the gorilla’s food and habitat requirements. Was Mikeno representative of the park? How much did the gorillas actually consume of the different foods available to them? Did they have preference? If so, were choices based on quality or availability? Ultimately, could the now diminished forest meet their long term needs?

ONE DAY IN JUNE, as our first long rainy season approached its end, hearing a noise, she looked away to see who was moving through the thick under growth nearby. She had not yet seen all members of group 5 and wanted to complete her daily count. Reassured that patsy and Muraha were accounted for, she turned to find that Beethoven had moved silently behind her, where he was reaching for a plastic bag she stuffed with Gallium. Amy reached as well, but lost the race. Beethoven grabbed the bag, stutters a few feet away, and sat down with a confident look. As Amy watched in bemused shock, he reached into the bag and began to cram folded “wedges’” of Gallium into his maw, chewing steadily until he finished his meals. Dropping the bag by his side, he then nimbly removed a few strands of the clinging vine from his hairy forearm and ambled off to nap.

For Beethoven, this was a déjà dinner. For Amy it was lost data. As part of her research,, she would monitor one group member for five hours almost every day. During that time she recorded everything the individual ate, what was within reach but was not eaten, and what other gorillas within view were eating. She had devised a simple method a simple method to determine quantities of food consumed replicating each individual’s feeding by sitting nearby and gathering equal quantities whatever was being consumed. When the feeding was over, Amy’s duplicate meal was bagged, brought back to our cabin to be weighed, then dried for later nutritional analysis. She had any qualms about choosing foods of similar quality to those eaten by the gorillas; Beethoven certainly dispelled them on the day of the great gallium heist.

Within a few months, the gorillas of group 5 completely tolerated Amy’s almost constant presence. Every other day, she would leave the cabin at the break of dawn and hurry off alone to catch the group before it began feeding on rainy days, she would often find the entire group still in bed. Most other mornings she might find several adults still lounging sleepy-eyed in their night nests, provoking nothing more than a few belch vocalizations. Amy returns the two tone sound, like a deep clearing of the throat, to acknowledge her presence. The young gorillas were usually already up and active, waiting for their parents like eager children on Christmas morning. After the last adult rolled out of bed, a decision would be made in silence and the group would move off behind either Beethoven or an older female like Effie. At this point, Amy would move close to her focal animal and stay near that individual thought the morning. On alternate days, when she did five hour afternoon focal as intensive observation periods were called, she would catch up with the group in late morning and then stay until their last feeding session ended and they began to make their nights nests.

Amy’s discovery that the gorillas were more at ease when she stayed close to them opened a new window on the world of gorilla feeding ecology and behavior. From three to six feet away, every thorn on a thistle, every stinging hair on a nettle, is clearly visible. These were important foods for the gorillas, though ones they treated with respect. The long leaf of a thistle plant provided a natural sheath into which the gorillas would carefully fold the spikes along the leaf’s edge. The gorillas then strategically placed this packet in the side of the mouth and ground it under the crushing power of their molars. Nettles received similar treatment, though in this case the gorillas would slide under sides of two fingers up the stalk, collecting all the leaves in a bundle with the irritating surfaces pressed against each other and away from their skin. Then they twisted off this turf and consumed it with the stinging hairs aligned away from the point of entry to the mouth. Gorillas apparently tolerated the natural defenses of these two plants because of their combined nutritional and high water content. Only wild celery contained more liquid, which would sometimes run down the gorillas chins as they chewed noisily on the hearty stalks. Celery was also the most palatable of these plants to our tastes, though we had to be terribly thirsty to tolerate the bitter after taste of its young stems. Amy sampled nearly all of the gorilla’s foods and came to especially appreciate mature celery as a midday drink substitute.

Bamboo was the gorilla’s most desired food. During the five months of the year when young shoots were in season, group 5 was never far from the lower elevation zone near the park border, where bamboo flourished. Here the gorillas spread out in a fan formation to increase their odds of finding the randomly located sprouts. As individuals discovered the three-to four-foot pointed shoots, they first looked over their shoulders for competitors, and then sat to enjoy the delicacy in private. After pulling the full shoot from the ground, they carefully unwrapped the pepper like sheaths and noisily devoured the succulent core. As they moved on, neat circular piles of spiral wrappings were left in their wake, helping Amy to track the group across the generally bare terrain beneath the full cover of bamboo. This canopy was broken in some places and bamboo mixed with other plants. One plant that broken in some places and bamboo mixed with other plants. One plant that thrived under these conditions was Droguetia, a vine covered with one to-two inch-long leaves. The gorillas had a fondness for Droguetia, especially in combination with bamboo. Later analyses would reveal that this was not just a taste preference but a powerful form of nutritional complementarily.

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