Zoobiquity (36 page)

“
Mobbing is a way to impress upon the whole community that something dangerous is near,” she told me. “If the whole group is making a huge racket, that helps younger animals learn the community’s predators.” Mobbing, she continued, is also safer than solo inspection. Young animals, she said, “aren’t very good at evading predators.” Moving
toward danger in the protection of an adult-led mob provides youngsters with a safe and educational close-up view.

When I was in high school, I went through a quintessentially American rite of passage: I took driver’s ed. Several decades later, the physical skills of steering, scanning the road, and signaling have become so engrained in my muscle memory, I really don’t even remember learning them. But one part of driver’s ed remains seared into my mind. Along with generations of neophyte drivers in California, I was made to watch a film called
Red Asphalt
. Produced by the California Highway Patrol, the movie shows scene after gory scene of traffic accidents. Blood rushes down gutters. Bodies lie akimbo under cars. Motorcyclists’ limbs are smeared across the pavement. Drivers who spent their teen years outside California might remember being traumatized by other pieces of edu-propaganda, such as
The Last Prom
, which featured a crushed and bloody corsage on the side of the road, or videos with cautionary titles like
Wheels of Tragedy, Mechanized Death
, and
Highways of Agony
.

Movies like these have been terrifying teens for decades. Seen from an animal behaviorist’s perspective, though, they may simply be a cinematic tool adults have created to compel human adolescents to inspect their biggest killer: motor vehicles.

Although the threat posed by cars is new, the techniques employed by
Red Asphalt
are age-old. From frightening campfire stories of what lies in the woods to 3-D surround-sound gorefests, human culture routinely uses tales of murder and peril to scare and then instruct. Not only are they age-old, but they’re also incredibly popular. And who’s drawn to them? Adolescents. Hollywood is populated by wealthy producers who figured out that, like young animals, teenagers will flock to horror movies and gaming worlds their parents have outgrown. A quick glance at the line for a monstrous roller coaster will similarly tell you all you need to know about which age group is drawn to the simulated danger but chemically identical adrenaline rush of a perilous fall. We may not think of these mass entertainments as evolutionarily linked to the antipredation strategies of other animals. But just like mature animals mobbing predators to teach youngsters, human grown-ups write the stories, produce the movies, and build the roller coasters—making money off teens’ inherited physiological craving for calculated risk.

Learning to deal with threats doesn’t involve only confronting them
head-on. It also involves learning when and how to hide from them. For every parent who’s been frustrated by a teen who won’t meet their gaze, consider what direct eye contact can mean in the wild. It often means you’ve been targeted. While baby animals often stare at everything around them, adolescents must learn that catching the gaze of the wrong set of eyes can be deadly.
Looking-away responses have evolved in many animals, from mouse lemurs to jewel fish. Staring at chickens and lizards causes them to become rigid.
House sparrows take flight more readily when eyes are directed at them. Gaze aversion in animals begins during the transition from infancy to adulthood.
Studies of humans note a surge of eye gaze aversion in the preteen and teen years.

While young animals are learning how to be vigilant, they can at times be overattentive, identifying threats where none exists. Some overreact to every rustling leaf, looming shadow, or strange smell. I once watched a group of about thirty sea otters startle at a loud noise that turned out to be a false alarm. As the frightened animals raced away to the other side of the lagoon, the adolescents led the way, cutting through the water with full-out swimming strokes. Leisurely pulling up the rear, carefully keeping their heads dry, were the mature otters, who’d had more experience with true danger.

As they test their danger-detection skills, inexperienced yet eager-to-learn vervet monkeys, beavers, and prairie dogs often cry or scream out unnecessary alarm calls. The older members of the group can be surprisingly forgiving toward youths who cry wolf (or jaguar, snake, or owl)—responding with a reassuring return call or simply ignoring the errant signals.

But learning to recognize and avoid predators is really just preparation for a vastly more important and riskier moment in most young animals’ lives: leaving the nest.

The young of many species leave their families in adolescence, sometimes for a temporary journey of discovery, sometimes for good. Leaving home, a process behaviorists call “dispersal,” varies from animal to animal, by species, and by sex. But whether undertaken by a caterpillar or a zebra, it’s an exceedingly dangerous time of life.

Vervet monkeys make an interesting example because their social progression parallels many classic human tales of young men going off to prove themselves. These clever, cat-sized primates, found in sub-Saharan
Africa and on the Caribbean islands of St. Kitts and Barbados, have gray-green fur on their backs, whitish bellies, black faces, and wide, soulful brown eyes. Vervet childhood will sound familiar to many human parents. During an extended infancy that lasts for about a year, a baby vervet sticks close to its mother. At a year, the young monkey’s circle widens to include adult members of the group. Yearlings of both sexes play boisterous chase-and-wrestle games.

As they move into their second year—which corresponds roughly to eight to ten years of age in people—the boys’ play becomes more frenetic and intense. But the girls drop out of the rough-and-tumble games, their attention suddenly caught by different diversions: playing with infants and figuring out the social hierarchy in which they will spend their lives. Vervet females do not leave their birth group.

Vervet boys follow a different path. Males must strike out into the world on their own, leaving everything behind. Relatives and friends. Familiar foraging territory. Group and adult protection from predators.

But danger comes not just from isolation and the predators they may meet along the way. It’s also in the social minefield they’re heading into. They must join a new group of monkeys. Approaching and integrating into a vervet group makes our tortured process of applying to college or getting a first job seem almost easy. All alone and newly independent, the adolescent has to first locate a group of strangers. He has to approach them. Then he has to threaten, challenge, try to intimidate, and, finally, fight the dominant, mature males. But diplomacy is critical. If he comes on too strong, he will lose the respect and tolerance of the females in the group—which can be a deal breaker, since vervet groups are matrilineal and females wield the power. Vervet females will not tolerate being threatened. Scaring babies is also strictly taboo. So while he’s trying to intimidate the males, the adolescent newcomer has to simultaneously charm the females.

Lynn Fairbanks, a professor of psychiatry and biobehavioral sciences at UCLA, has spent more than thirty years studying wild and captive populations of vervets.
She told me that these weeks of male transition are extremely stressful, yet exceedingly critical. How the adolescent performs may affect his status and his access to mates, food, and shelter for the rest of his life. And intriguingly, Fairbanks has discovered that the males who transition most successfully are the ones that show a special willingness to “go for it.”

As she told me, in vervets, a degree of impulsivity may be “necessary.” It motivates males to leave home and take on the challenges and risks of getting into a new group.

While most vervet immigrants have to settle for second-tier status, the ones who become alphas in their groups share another common trait. Their brashness emerges strongly during adolescence but doesn’t stay at peak intensity forever. After they achieve dominance, their impulsivity sinks down to more moderate levels. Fairbanks writes that her findings support “
the idea that an age-limited increase in impulsivity in adolescence is not a pathological trait, but instead is related to later social success.” In other words, acting a little cocky when you’re a teen may not necessarily mean you’re going to turn out to be a wild adult. It might even push you up the social ladder.

A similarly lowered risk threshold—indeed, a new
pleasure
in risk taking—likely propels nearly grown birds out of nests, hyenas out of communal dens, dolphins, elephants, horses, and otters into peer groups, and human teens into malls and college dorms. As we’ve seen, having a brain that makes you feel less afraid enables, perhaps encourages, encounters with threats and competitors that are crucial to your future safety and success. The biology of decreased fear, greater interest in novelty, and impulsivity serve a purpose across species. In fact, it could be that the only thing more dangerous than taking risks in adolescence is
not
taking them.

Linda Spear, a professor of psychology at the State University of New York at Binghamton and the author of
The Behavioral Neuroscience of Adolescence
, agrees. During years of studying the neurology of humans and other species, she has observed “
age-specific behavioral characteristics.” She explains that, although we notice behaviors in the context of what we call human “culture,” adolescent transformations have biological underpinnings and “
are deeply embedded in our evolutionary past.”

In other words, what we observe as uniquely human adolescent behavior may in fact be shared physiology at work. Admittedly, humans do have a unique ingenuity for amping up the danger. When an adolescent rat or vervet monkey impulsively bursts out to explore something new, he’s not also piloting a two-ton SUV full of his friends. A gazelle in thrilling pursuit of a cheetah isn’t also tripping on the latest designer drug.

For human parents, knowing that brain and body shifts are causing
predictable and universal behaviors is not going to relieve the worry of late nights or the anguish of seeing a tattoo around the ankle of a formerly straight-arrow daughter or son. It certainly won’t ease the grief of a parent who’s lost a child to what seemed like extreme or unnecessary risk. But putting adolescent impulsivity in a context that sees it as not just normal but physiologically and evolutionarily necessary may make bewildering behavior slightly more bearable.

A number of miles south of the Triangle of Death, near the Moss Landing power plant and slough, there’s a sheltered lagoon. Beginning kayakers come here to practice paddling. Ecotourists can board an open-air safari boat to view harbor seals and pelicans. But the sightseers’ biggest draw is a group of fifty or so sea otters calmly rafting, grooming, foraging, sleeping, spinning, and occasionally wrestling in the tranquil water.

I spent an overcast August morning observing the Moss Landing otters with Gena Bentall, a research biologist for the Sea Otter Research and Conservation Program at the Monterey Bay Aquarium who has spent thousands of hours documenting the behavior of these marine mammals. As her beagle, Harry, watched from his special bed in the back of her pickup truck, Bentall and I discussed the single distinguishing feature of this otter group: they’re all male. Ranging in age from sleek, dark adolescents to grizzled mature adults, these he-otters use the Moss Landing site as a stopover rest area. After swimming long distances along the California coast to breed, explore other territories, or challenge other males, an otter will pull into the Moss Landing lagoon. Some are full-time residents. Some show up only at night. For some, the Moss Landing group is a part-time sanctuary. Food is plentiful; predators are minimal; responsibilities are few. It’s a place where territorial males can pass time in a nonterritorial mode and young males can learn the ropes. The relaxed camaraderie of the group reminded me of a men’s locker room—a place for growing and grown men to gather, groom, eat, nap, socialize, and play … without having to compete for females.

Adolescent male dolphins, elephants, lions, and horses, as well as the teen males of many primates, join so-called bachelor groups like this in the period between leaving their birthplace and starting their own families.

Adolescent African elephants, for example, use them to prepare for the “ritualism of male-male competition,” by sparring with other males their own age. According to biologists Kate E. Evans and Stephen Harris, of the University of Bristol, adolescence is an “important learning period” for these young pachyderms, a time of transitioning from “the highly structured breeding herd” to the “much more fluid social system of adult males.” Bulls fake-fight with each other as adolescents to determine who is dominant at that moment, and to learn the rules of “bull society.”

These groups of young male elephants are especially friendly compared to groups of older animals; they greet one another with gestures like trunk entwining, ear flapping, trumpeting, and joyful defecation.
Gena Bentall has cataloged similar familiar greeting behaviors among groups of sea otters, who shove, stroke, nose, and sniff one another.
Male wild horses and zebras, which also migrate into all-stallion groups when they leave their birth herd, at about two or three years old, bond through roughhousing and frisky urination.
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Evans and Harris spotted a notable interloper in the adolescent elephant groups: older male bulls. But instead of treating these older males as unwelcome chaperones, the younger elephants seemed to prefer having them around. Evans and Harris write that the elders serve as mentors, socializing the younger elephants and helping them learn to “become dominant males without posing a competitive threat.” They also reported that the presence of the mature bulls seemed, in some cases, to suppress testosterone-driven pugnacity in the younger animals.
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Sea otter bachelor groups also include males of mixed ages. Although Bentall did not speculate on whether the presence of the older males affected the younger males hormonally, she said that one of the ways the Moss Landing adolescents find their way to the sheltered lagoon in the first place is by following a mentor male.