Umoja (as yet un-named) at the age of one year and two months, after recovery from respiratory disease, with Nyiramurema in April 2007

I have a special feeling for the young gorilla Umoja, since I was the one who had the honor of naming him two years ago, at the annual ceremony in which infant gorillas who’ve survived their first year are given the names by which we know them.  Umoja means “unity”—chosen because I was there as a representative of the non-profit conservation agencies working together in Rwanda.

April and May have been full of drama for Umoja—for three years in a row!
I was on my way back from a routine field check the other day when the radio chatter in Kinyarwanda suddenly intensified.  After the word “silverback” came through loud and clear, I asked for a translation, expecting to hear details of an injured gorilla, or worse.  Sure enough, there’d been an interaction between Umoja’s family, Kwitonda Group, and a visiting group from Uganda, Nyakagezi Group.

Umoja with Nyiramurema just before the naming ceremony on June 8, 2007, surgery April 26 2008

This is bamboo-shoot season in Kwitonda’s home range and this is probably the reason for Nyakagezi Group’s annual visit to the area.  Since these two groups often interact peacefully at other times of the year, it seems the prized bamboo shoot is the source of aggression.  Nyiramurema’s behavior may also have been a factor.  Maybe she’s been trying to transfer for some time. I held my breath, waiting to hear more, and glanced at the date on my watch: April 27, 2009.  It had been almost exactly a year (April 24, 2008) since Umoja nearly died in a fight between the same two gorilla groups.

I’ll always remember that day vividly, along with those that followed.  Somehow Umoja survived his initial injuries: two canine wounds in his abdomen that left two loops of bowel hanging outside his body; a partially severed right wrist; and a broken right leg.  Because such interactions are a natural part of life for wild gorillas, we were unable to intervene—and in any case, the two groups were still very close to each other.  We visited the Kwitonda group briefly, long enough to see the injured Umoja from a distance.  He was whimpering, unable to keep up with the group on his own.  Using his left arm and leg, he could only pull himself along the ground.  I felt heartsick, knowing that he would suffer.  His injuries assured him of a slow death, rather than an immediate one.  I’d treated an infant zoo gorilla once for herniated intestines and knew that if we could do surgery right away, Umoja would survive.  But I had to agree with our guidelines that this wasn’t a case for intervention, at least not on that day.

Three days later, all was calm, and Umoja was still alive.  It was amazing to watch his family take care of him, cleaning his wounds and carrying him around.  He was lucky that his intestines weren’t actually damaged and continued to work, even with a portion hanging outside his body.  We worried about abdominal infection; moreover, the puncture wounds were healing and would soon begin to constrict the gut.  Given the quiet mood of the group, we decided to try surgery in the field after all.  It took me a day and a half to get the darts off, since we knew that family members were primed to pick Umoja up if they saw him on the ground.  I had to wait until his mother, Nyiramurema, was more or less alone.  When I finally fired, most of the family was all around us eating in the trees.  The vegetation provided perfect cover.

Umoja before surgery April 26 2008

The day of the surgery was both exhausting and exhilarating.  I had a challenge keeping two gorillas anesthetized—Umoja and Nyiramurema—while Magda did the surgery, given the circumstances, and Elisabeth did everything else.  We worked quickly, especially Magda, who skillfully dealt with both the herniated intestines and the severed wrist in little more than an hour.  The procedure went well to the point where we woke up mother and infant together.  The reversal drugs had worked perfectly; Nyiramurema was alert and Umoja holding onto her in normal fashion.  Then came the really scary part:  Nyiramurema began the search for her family, but followed an old trail.  She went downhill instead of up.

Nyiramurema’s eye injury

It didn’t help that Nyiramurema was blind in one eye and lame (she’d lost a foot years ago, probably to a snare.)  Between these disabilities and the after-effects of the anesthetic, she was very unstable.  As she wobbled and tumbled through the forest, searching for her family, Umoja hung on as best he could.  We hated to think of his being dragged through the heavy vegetation, but there was nothing we could do at that point except help try to redirect his mother.  The trackers fanned out to head her off while Magda, Elisabeth, and I struggled to keep up.  We pushed through a clump of bamboo in time to see Nyiramurema pause, looking for a new trail.  Umoja, tired of hanging on and drenched from the wet vegetation, slid off her back onto the ground.  His mother glanced at us, at him, and then at the trail ahead, and took off.  For whatever reason, most likely a combination of confusion and fear, she left Umoja there on the ground.  Her group was now at least a kilometer away.  We waited a few minutes to see if she would return.  Meanwhile, Umoja lay on the ground with his hands on his head, losing body heat.  We had no choice but to pick the infant up and make our way to the group as fast as we could, hoping to intercept his mother.

An hour later, I finally put Umoja down on a fresh gorilla trail, and in less than a minute, Nyiramurema appeared from a clump of trees to my right, with the rest of the group not far to my left.  The mother picked up the infant on her way by us as if nothing had happened!  From that point on, he healed steadily.  Within a month, Umoja could walk, and within two months he could use his wrist almost normally.

Umoja in July 2008, 3 months after surgery using left arm

Now, a year later, it seemed that Umoja was in trouble again.  I drove quickly back to the office, though I knew we wouldn’t be able to intervene immediately in this case either, no matter what had happened.  Then came the good and bad news.  Umoja was fine, but his mother Nyiramurema was gone.  She was with Nyakagezi Group.  Though it’s not the image we have–a big male gorilla pulling a female along with him—this transfer was largely Nyiramurema’s choice.  When there’s a desirable silverback in the vicinity, it’s the female that decides whether or not to change groups.  Her immediate family fights to keep her.  I wondered if this had been the reason for Umoja’s injury a year earlier.  Perhaps his mother wanted to leave the group, and little Umoja had gotten caught in the middle.  This time, he must have known to keep his distance.

Had Nyiramurema transferred a year ago, Umoja would have died.  At two years old, he was still completely dependent on his mother for milk.  If she’d left with him, the silverbacks in Nyakagezi group would surely have killed him—and had he stayed without her, he would have starved.  My first reaction when I heard this latest news was to wonder if he was old enough now to survive without her.  I tried to calculate Umoja’s exact age.  Three year olds can handle sudden weaning, though they do undergo considerable stress.  If they’re younger, the chances of survival go way down.

Umoja in July 2008, 3 months after surgery

I was almost sure Umoja was old enough to survive.  My history with this infant had begun in April 2007, when he (as yet unnamed) and Nyiramurema were both ill from respiratory disease, along with every other gorilla in Kwitonda Group.  When the pair suddenly went missing, we pulled the whole team together and finally found them after five days, still coughing but alive, and guided them back to the group.  This effort led to the honor I mentioned early—the naming of Umoja at the annual ceremony.

I ticked off the months in my mind. Gorilla infants are never named until they’re at least a year old, so he had to be almost three by now (the naming ceremony in 2007 had taken place in June).  Nevertheless, I didn’t stop worrying about Umoja until I got back to my office and checked his birth date: February 2006.  Whew.   Three years and two months.

Umoja (right) in November 2008, 6 months post-op, with Sulibika (left)

This was another hard fact of gorilla life.  Group interactions and female transfers occasionally do result in premature weaning, and there’s nothing we can do about it.   The infant must suddenly survive on calories from plants instead of calories from milk, and without their mother’s warmth, they burn even more energy at night.  What we usually see even in the older weanlings—those weaned at a normal age—is a change in behavior.  Instead of playing, they eat incessantly, and pout.  Their body shapes change, too, as their bellies enlarge and they lose their baby fat.  When the stress of the change is severe, they develop edema (fluid) in their face and hands, a sign of mild hypothermia.

Umoja eating near Kwitonda, April 28 2009

Of course, I went to check on Umoja the next day—not because we’d intervene if he showed signs of weaning stress, but to document it.  The second silverback and a blackback in Kwitonda Group had also been injured during the fight, so I planned to check them, too.  As it turned out, Nyakagezi was still around, which made for a bit of tracking confusion.  We could hear three different chest beats from three locations, and found ourselves following multiple trails that crisscrossed each other.

After we’d tracked for three hours, the first gorillas we found were making no noise at all.  Indeed, we didn’t even find them.  It was the Nyakagezi Group trackers who called us to their location.  After checking nose prints, we confirmed that these four juveniles indeed belonged to Kwitonda Group.  But the silverback, Kwitonda, was not with them, nor was Umoja or the rest of the family.  The Nyakagezi trackers continued uphill in the direction of the most distant chest beats, and soon confirmed by radio that they’d found the group—and Nyiramurema.  Meanwhile, we continued to follow various trails that seemed to go in circles.  Finally, we found the main trail and most of Kwitonda Group in a dense cluster of bamboo.

Umoja eating April 28 2009

Kwitonda was eating bamboo shoots in company with his remaining five adult females and their offspring—as well as Umoja.  I was relieved to see Umoja sitting calmly next to his father, as he often did.  On my last few visits to the group, I’d rarely seen this infant with his mother.  He’d grown up quickly, perhaps because of his injury and her disability, and was already very independent.  Even so, his expression was not as relaxed as it normally was.  His lips were pursed, his eyes wide.  The same thing was true of the other gorillas we’d seen.  I’m sure they’d all been covering much more ground than usual.

Over the next hour, Umoja spent most of his time eating bamboo, as did the rest of the family.  He didn’t play much; but the whole group had clearly been through a stressful morning.  It’s too early to tell how much his behavior will change as a result of his sudden weaning, or if he’ll develop the facial swelling I mentioned earlier.

We finished our check by looking for the third set of chest beats.  We finally caught up to one of the young silverbacks and two black backs from Kwitonda Group.  As the tracker explained, they were still on patrol looking for Nyiramurema.  One had a minor scrape on his back and the other had lost his little toe (ouch!) but these were minor wounds for male gorillas.  Either they hadn’t fought very hard to keep Nyiramurema or realized they didn’t have much of a chance.  Maybe they figured, as we did, that she’d try to come back.  Because of her handicaps (one eye, one good leg), it’s doubtful that she can keep up with Nyakagezi Group.  These gorillas routinely travel far and fast, from Uganda to Rwanda and back again, and then into Congo.

Umoja eating near Kwitonda, April 28 2009

Though I hate to think so, maybe Umoja is simply an infant destined not to survive.  If he has trouble now, as a result of his sudden weaning, there’s nothing we can do.  We’ll know in another week or so.