A day with Flakes group

My alarm goes off at 3:15 am.  I gently wake Kate, who is a better sleeper than I am, and she shuffles into the kitchen to get some breakfast while I get dressed. I hear a little squeal of delight from her, which I assume to be associated with the discovery of some particularly nice breakfast item.  Soon, however, I am proven wrong when she opens the door, grabs her camera and says “Mommy, come see!  There’s a tarantula on the mattress!”  We had spent some time the previous day reading a wonderful book about tarantula behavior and anatomy, and we eagerly crowded around the tarantula, taking note of all the anatomical features we had learned about the previous day.

Kate admiring a tarantula. Photo: S. Perry

There isn’t a lot of time to dawdle over the admiration of tarantulas, however. So we reluctantly put away the camera, gulp down some tea, and rush to the porch to pack our bags and put on our snake leggings.

There was a full moon last night, and this often means trouble, because the monkeys can see well enough  to get up  in  the middle of the night and move  to a  different sleep site. Indeed,  when we get to  the sleep site, there is no sign of monkeys, though we are treated to the sight of a cuyeo(nightjar) doing a broken wing display to distract us from the location of its nest on the ground. I send David and Summer to search one stream while Kate and I search another.

We start by opening our ears, removing our “monkey filters” and trying to identify every sound we hear.  The human brain can’t possibly process every sound that is being emitted in a tropical forest, and normally we are so focused on the monkeys that we honestly don’t notice much besides the sounds produced by monkeys, just as humans are capable of blocking out street sounds and music in order to focus on a human conversation.  At this moment we hear howler monkeys, clay-colored robins, banded wrens, rufous-and-white wrens, tinamous, frogs, and at least 6 bird species I can’t recognize – familiar sounds I hear regularly but have never observed being produced. Most of these sounds appear to be “conversations” – we hear exchanges of the same vocalizations across large distances.  Kate and I try to speculate what all of this means.  Are they trying to attract mates? Defend territories? The forest is chock full of unanswered questions. It is sobering to think of the thousands of species that inhabit this endangered forest, most of which will never be intensively studied enough to answer even basic questions about their behavioral biology. Around 5:30 am the sound of traffic on the nearby Pelon highway starts, reminding us that this wilderness area is not as large as it feels, despite the fact that we generally go all day without seeing another human (aside from our fellow primatologists).

Soon I catch a strong whiff of monkey poop.  And not just ANY monkey poop: clearly this is capuchin poop.  This is not a smell that would appeal to most people; it is highly pungent and definitely not the sort of odor that inspires an appetite for breakfast. But to me, it is the smell of data, and the smell of a fun day with one of the world’s most fascinating animals. I radio David and Summer to say that I’m on the trail of the monkeys, but to wait until I’ve found the actual monkeys to join me. Then I set off down the river, following one of their travel routes till I smell yet more monkey poop, even fresher than the first.  I pause to listen, and sure enough: there they are, hopping from branch to branch. I radio to Summer and David to tell them the good news and then whoop twice so that they can hear where I am. Our whooping system (invented by our field assistant Alex Fuentes,  18 years ago) is a bit like the monkeys’ “lost call” system. If I whoop once it means “I am here, where are you?” Two whoops means “I’m with the monkeys!” and three means “Emergency! Come help me!” Summer whoops back once, letting me know that she has received my message. A few minutes later, David and Summer appear.

“Your whoop sounds like a pig wrangler’s, Summer,” David says companionably, renewing an argument from earlier in the day.  “It’s really making me question—did everyone in your cohort sound like that?”

Summer snorts indignantly.  “Everyone keeps saying that!  My whoop is perfectly normal, thank you very much!  And it carries!”

 “I’ve always wanted to look at the cultural transmission of whoops from cohort to cohort,” I say thoughtfully.  “We could set up a database with a recording of each person’s whoop—sort of like a dolphin’s signature whistle.”

We climb a rocky outcrop, searching for our first focal animal, and stumble across a peaceful scene: two low-ranking and mild-mannered females are tucked away in a bush, looking drowsy and cozy. Both of these sweet females have names of male TV/television personalities who bear absolutely no resemblance to these monkeys. The first field assistant to discover a newborn baby gets to name it, and often monkeys are named after people’s favorite movie stars, actors,  singers, friends or relatives. It is essentially impossible to sex infants during the first months of their lives, due to the extraordinarily large clitoris (with a bone!) possessed by females, which quite effectively mimics male genitalia. Monkeys need a name from day one, however, and this results in some wild mismatches between monkeys and their namesakes, both with regard to gender and personality. In the current scene, we have little Bruce Willis trying to sniff her girl friend Larry David’s hand, while Larry snoozes.  Bruce gently attempts to insert Larry’s finger up Bruce’s nostril.  The alpha male Madison is sleeping ten lengths away.  Larry eventually rouses herself from slumber and cups her hand over Bruce’s nose. After a few peaceful moments of zen-like handsniffing trance, Bruce shifts position, presenting the upper part of her body to Larry in a request for grooming.  But Larry wants to keep handsniffing: she once again cups her hand over Bruce’s nose. They look so relaxed and peaceful, so devotedly in tune with one another! These moments of relaxation are rare in the life of capuchin monkeys, whose days are generally packed with foraging challenges, political drama, and predator encounters, all of which are dealt with at high speed.  Hand-sniffing isn’t a standard type of social interaction for capuchins.  Rather, it is a venerable tradition that was invented by females in Flakes group, which has been passed down from friend to friend. Only monkeys who have a really solid friendship will handsniff, because it requires a lot of trust to let someone put their fingers, equipped with long, dirty fingernails, up one’s nose.

Billie (right) sniffs Larry's hand. Video: S. Perry

In this case, the peaceful moment doesn’t last long.  Excalibur, the 7-year-old adolescent son of the alpha female, rushes over and bites his cousin Larry David, causing her to roar with fear and rage at this extraordinary injustice.  Excalibur is at that irritating age in which he has finally realized that he’s big and strong enough to take on the adult females who have been disciplining him for his entire infancy and juvenile phase. Adult males are all typically dominant to adult females, and part of Excalibur’s strategy for acquiring this exalted adult male status includes bullying adult females when they least expect it, to get them to acknowledge his superiority. Bruce Willis, who is quite familiar with Excalibur’s approach to life, skidaddles to avoid attack instead of helping her friend. Excalibur escalates his  antagonism of the irate Larry, pinching her, chasing her and pulling her tail. Then he whacks her as hard as he can; throughout all of this abuse, she screams continuously, at top volume, the pitch of her cries rising and falling in waves as she lunges back at him.

Excalibur. Photo: S. Perry

Capuchins are meddlesome, opinionated creatures by nature, and the many monkeys who had been grooming or napping now rouse themselves to voice opinions about the developing conflict. Madison, the alpha male, is starting to get more interested. He opens his mouth in the classic silent threat face while glaring at the proceedings, but because the two squabbling monkeys are practically on top of one another, we can’t tell which of the two he is supporting. Larry’s brothers Flamenco and Ray begin threatening in the direction of the conflict as Excalibur and Larry repeatedly slap one another in the face. Excalibur lunges at Larry. Excalibur’s mother and sister and a distant juvenile threaten as well; everyone seems outraged by this high volume conflict during nap time. Larry starts to back away from Excalibur as he repeatedly lunges at her; although she seems to be conceding defeat, she continues to vocally express her extreme displeasure, as if to say “you’re getting your way THIS time, but just you wait!” As Larry finally turns tail and flees, hotly pursued by Excalibur, Excalibur’s sister Viola screams, this time clearly at Larry. In general, capuchins tend to follow four rules when deciding whom to support in a conflict, but they can’t follow all of these rules simultaneously. They support females over males, dominants over subordinates, better friends against less close friends, and closer kin over less close kin.  In this case, loyalty to closest kin seems to have swayed Viola’s decision.  Poor Larry.  

Viola threatens monkeys in an on-going fight. Photo: S. Perry

Later in the day, Bruce Willis is resting with her little sister Billie.  Billie is a favorite of ours because she survived, despite having been orphaned at the tender age of 5 and half months.  Infants usually keep nursing for up to two years of age, when their next sibling is born. The other females in the group gave Billie milk handouts, but she still didn’t get nearly as much as she would have had her mother survived, and her size shows it.  Even as an adult, she looks much smaller than other monkeys her age.  But she was really clever about knowing when to scream and when not to scream in order to get her way.  She loudly protested bullying from her bigger age mates, and was an odd mix of sweet and stubborn. But when fighting a losing battle, she was also capable of being stoic. Her father, the alpha male Quijote, was very protective of her and invented many fun games to play with both Bruce and Billie, which usually involved them sucking on his fingers or manipulating his face in amusing ways. Perhaps her small size buffered her a bit from attacks by adult females, enabling her to survive.  She tends to hang out on the edge of the group, avoiding trouble, except when she joins in rowdy play bouts with the group’s infants and juveniles, where she is barely distinguishable from the kids due to her small size.

Today, however, what Billie really wants is a quiet nap with her sister Bruce.  This, unfortunately, is not Excalibur’s plan for her. Excalibur has recently invented a fun (for him) way to interact with napping adult females. He runs over to them and uses both hands to whack them as hard as he can on the back, using their bodies as drums.  It is incredibly loud!  Ouch! For the first twenty seconds of this percussive assault, Billie keeps her eyes closed and pretends not to notice, apparently hoping that if she doesn’t react, Excalibur will go bother someone else. But finally he hits her so hard that she slips off the branch, yelps in surprise, and then makes a dignified retreat to a different tree to finish her nap. She doesn’t seem scared of Excalibur the way Larry was earlier.  She just shrugs it off as if to say “Boys will be boys” and continues with her day. What a tough little monkey!

Billie plays with her nephew (Bruce's son). Video:  S. Perry