A Visit with Peter Cook at Long Marine Lab’s Pinniped Cognition & Sensory Systems Laboratory

Peter Cook with one of the sea lions he works with, Ronan (NMFS 932-1905/MA-009526)

“Pea soup” is a northeastern term: dense, intractable fog, the kind that causes to you to creep along in your car at ten miles per hour, because you can’t see more than six yards ahead. But it’s not Maine or New Brunswick or Nova Scotia, rather the infamous Devil’s Slide on California’s Highway 1. Giddily looking forward to driving south from San Francisco, I had chosen the coast road over a six-lane highway, only to find my impish hopes for a vista-filled drive foiled by a thick veil of fog. I gingerly steer my car through the narrow, sharply undulating road, to the left a crumbling cliff goes up a few stories high and to the right it plunges abruptly a hundred feet or so into the sea. Happily the guardrails are pretty sturdy.

After a few miles the road straightens out, at least a bit. On days like this in the springtime, when the yellow mustard grass is blooming and the landscape is rife with lush, new growth from the winter rains, the porous fog softens the boundary between land and sea. Salt smell fills the air and in the small inlets of the coast you can see interwoven patches of kelp, creating forest-like underwater canopies of magnificent diversity. I’m headed south to Santa Cruz to interview Peter Cook, an expert on sea lion cognition working in Dr. Colleen Reichmuth’s Pinniped Cognition & Sensory Systems Laboratory at Long Marine Lab.

Pinniped. Now there’s a word! Pinna means “wing” or “fin” in Latin, and ped means “foot.” So, pinniped means “fin-footed mammal,” that wide array of amphibious marine mammals, such as seals, sea lions and walruses. Ever since my husband aided in the rescue of a stranded sea lion, I had become fascinated with them and finally decided to write about their life in the densely rich habitat of the Pacific Coast.

The more I learned the more curious I became. Sea lions find their food in the sea, but give birth on land. They can dive to more than 1000 feet and swim at cruising speeds of over 10 mph; it’s believed their long ultra-sensitive whiskers (called “vibrissae”) help them hunt for fish in dark, deep waters and they hear equally as well below the water as on land, hearing sounds over a mile away.

My research whizzed along joyously until I hit one of those moments which truly contrasts superficial knowledge with deep experience. I’d heard of “marine-mammal entanglement,” I knew “what” it was, but having acquired a much richer appreciation for the lives of pinnipeds, it now struck a much deeper chord. The statistics are sobering, the photographs heart-wrenching: motionless harbor seals dead in abandoned fishing nets or with tracheas sliced open by fishing line tangled around their necks – all due to the destructive and unnecessary trail of marine litter we leave in the sea. Having myself survived a concussion underwater in a near-drowning accident, it was easy for me to imagine what that might be like. As a diver I’d always known to keep a dive knife strapped to my air gauge, should I be snared by fishing line.

As my fascination grew I wondered, was it that pinnipeds were warm-blooded, air-breathing mammals that I felt some special affinity for them? Or was it their dog-like muzzle and playful, wide-eyed gazes?  Perhaps it was my longing for the ocean – indeed if I could slip into the anatomical suit of another creature, the most seamless fit might be that of a sea lion suit. I’d love to grow wide flat fins and dwell in the sea for a while.

Cook’s research at Long Marine Lab was of special interest to me because it explored the cognitive characteristics of sea lions, their unique “habits of mind.” Cook researches the effects of domoic acid in stranded California sea lions. Domoic acid is a neurotoxin produced by a type of phytoplankton which is ingested through shellfish and anchovies. It damages the part of the brain that is responsible for long-term memory, the hippocampus.  Over the years I’d heard of it in relation to amnesiac shellfish poisoning in humans, which in severe cases can cause seizures and death. Cook’s research sheds light not only on this phenomenon in pinnipeds, but also the cognitive effects of amnesiac shellfish poisoning in human beings and the functioning of the human brain.

The fish we eat is routinely tested for such toxins, but such poisoning is becoming more common in marine mammals, which has raised concerns that human poisoning instances may increase or that low levels of the toxin may be creeping into the fish that makes its way to our plates. And there is the troubling speculation that marine pollution and global warming will further increase the kinds of algae blooms that produce domoic acid. So sea lions have a lot to tell us about the health of the seas, whether it be the effects of toxic algae blooms or the growing quantity of marine-borne debris. John Muir phrased it well, “When one tugs at a single thing in nature, he finds it attached to the rest of the world.”

I come around a long bend and into a straightway and I see an elongated bluff overlooking the sea and the faint silhouette of a few buildings. I bet that’s it, I think to myself.  Long Marine Lab is a cluster of low-lying structures with a small cheerful-looking visitor center and massive 87-foot blue whale skeleton right next to it. Dressed casually, wearing a green, paint-stained sweatshirt and a pair of Keen’s, Cook meets me in the parking lot and takes me into a gated area rimmed by weather-beaten redwood fences. I follow him down a walkway lined with perforated rubber mats bordering two large circular salt-water tanks, 20 to 30 feet wide.  The air is rife with loud splashing sounds. Shortly I would realize that sound was the non-stop, in-and-out of the water of the marine mammals there.

Through a mesh wire fence I see in one corner of a pool area the famed-veteran sea lion Rio, who has been at Long Marine Lab for over twenty years. If you’ve seen a domesticated sea lion on the Discovery Channel or PBS, it was very possibly her. She looks likes she’s sleeping and indeed does seem older compared to the aquatic antics of a much younger sea lion that Cook works with, Ronan. There’s so much splashing, it’s like a pool full of summer camp kids who’ve each guzzled a six-pack of Coke. Cook glances at my husband’s beloved Nikon D300 strapped around my neck and hints, “You might want to tuck that away.” I hurriedly stow it in my backpack. Then I cautiously bring my cheap point-and-shoot into the pool area. It’s soaked within a half minute.

Illustration of a sea lion pup

I imagine what Ronan might have looked like as a pup.

Ronan is about three years old and was rescued by the Marine Mammal Center in Sausalito when she was a newly-weaned pup. “She was really into people,” Cook tells me, “She kept coming up to people on the beach. She clearly was having trouble finding food out in the wild after her mom left her, which was the case with a lot of pups that year.”  Disarmingly playful and attentive, Ronan doesn’t miss a beat – she knows I’m new to the scene.  Cook explains that sea lions are sensitive to new people and much of it is through sense of smell. “I am one of the primary trainers for Ronan and she is quite different around me than around a lot of people. Rio is notoriously finicky about who she will eat from.  I’ll go up, or Colleen – who Rio knows really well – will go up, and Rio will be really great. Then a new volunteer will go up and Rio will be really hungry and they will give Rio a nice tasty fish and she will just spit it out, like ‘I’m not gonna eat from you!’”

Ronan eyes me carefully, curious. Her gaze reminds me of the probing looks our dog gives us at home. Sea lions are highly social, often gathering in large groups, resting draped over each other. “The pups will stay with their mom for six months, even up to a year sometimes,” Cook explains. “They have a really strong social bond with their mom. When the pup gets a little older the mom will spend more and more time at sea foraging – she has to get her resources up, her milk is extremely high calorie.” Cook goes on to tell me that a mother sea lion, when returning from foraging can find her pup by the sound of their calls and their scent in the midst of hundreds of other sea lions.

Cook prompts Ronan with a whistle though a number of drills – down, stay, leap, opening her jaws, lifting one fin or another as if to give a high five. Each motif punctuated by a silvery chunk of sardine which she gulps down. I’m struck by Ronan’s huge, soft, immensely expressive spherical eyes. It’s as if her eyes are small-scale satellite dishes in reverse, a marriage of acute sensitivity and exponentially wide scope. Cook explains how sea lions can see well both below and above water, one of the things that make them truly amphibious. Their large eyes, which have the same type of reflective layer that makes cats’ eyes glow in the dark, allow them to see in very dark, murky conditions, such as during deep foraging dives.  Scientists still don’t completely understand how sea lions see so well both underwater and in the air, but the ability is related to structural changes to the cornea and adaptations in muscular control over the lens.

What a marvel. The human eye doesn’t function well in water, so a diving mask works by creating a gap of air between our eyes and the water. Vision is gained, but at the cost of one’s peripheral vision.  How nice it would be to shed that clunky latex-laden glass mask underwater. What would it be like to have wide eyes that could change shape and focus whether in the water or in the open air? Each world, above and below water equally rich in experience.

Ronan gives my camera a wide-eyed gaze (NMFS 932-1905/MA-009526)

Ronan rolls sideways like a log back into the pool, seeming to enjoy the slow languorous roll into the water, yet one more jazzy improv on the inexhaustible choreographic possibilities of the space around her. Then with a flash she swims circles in the pool, carving arcs in and out of the water, moving at once with the precision and speed of a ballet dancer, yet with a torpedo-like strength and sureness, which allays any doubts in my mind about a sea lion’s ability to survive in the wild.  One more snap and she’s back in a seated position at the edge of the pool, ready to gobble another sardine.

Illustrations of Sea Lions SwimmingOne large part of Cook’s work with sea lions is testing wild sea lions for memory impairment. The Marine Mammal Center will send stranded sea lions they have rescued to Cook for several weeks of testing. Cook will study possible damage to the long-term memory component of their brain, the hippocampus. And while he’s testing them he collects data about their brain function. After he is done, the veterinarians at the Marine Mammal Center decide whether the sea lion can be released back into the wild.

Much of that testing goes on what’s called a T-maze, a wooden maze in the shape a “T” that Cook built to test their cognitive ability. The sea lion is trained to go down the center line of the T and then prompted to go either left or right through a swinging door. Cook tests the sea lion’s ability to learn and repeat left-right patterns. Another test uses multiple buckets, some containing fish, to probe long-term spatial memory – a very small-scale version of a daily foraging task. It’s a painstaking process, progress measured not in hours, but days of working with the sea lions.

Cook’s training begins with patient games of “hot and cold,” in which as soon as a sea lion gets close to what Cook wants, it is rewarded. Say for instance, he wants to train a sea lion to go down a ramp. So when the sea lion swims close to the ramp. Thwap! An anchovy appears. Then the sea lion puts its head at the top of the ramp. Thwap! Another anchovy. Then only if the sea lion puts one flipper on the ramp. On and on until the sea lion works up to more complicated tasks.

It’s not a stretch to compare the abilities of high-trained sea lion to the most astutely trained rescue dogs. Indeed the U.S. Navy has trained sea lions to act as underwater sentries in harbors, protecting ships from terrorists. The sea lions are trained to find swimming intruders and snap a locking clamp on the arm or leg of the intruder.  The clamp is attached to a line and the swimmer can then be reeling in. And of course, a sea lion can to this in a flash, so greatly outranking any human being in the water in agility and speed.

The T-maze (NMFS 932-1905/MA-009526)

Cook’s methods are especially unique because he works with wild sea lions, each one for a few weeks. Cook wanted to study wild sea lions, because it would give him a better window into the cognitive resources they use in their natural environment. Rio, for instance, the elder domesticated sea lion has, literally, a very different mindset. “She’s had twenty-five years of enculturation with people, hanging out with people, doing what they want her to do. It makes her very easy to work with, but we can’t be certain how closely she represents the cognitive faculties of animals living in the wild.”Studying wild animals like that falls into the diplomatically-phrased category of “naturalistic non-invasive neuroscience studies.” Generally neuroscience research using non-human animals is “non-natural” and “invasive,” which means conducted in artificial situations on creatures such as lab mice and monkeys that live their entire lifespan in captivity, many strains inbred for generations, developing behavioral adaptations to their constricted environments. And often these studies involve inflicting damage on otherwise healthy animals.

Many questions have been raised about these methods, especially the degree to which they really do shed light on the functioning of the brains of animals and humans. “You raise them in these incredibly impoverished environments,” Cook tells me, “and we know from human work and certainly other animal work, that the richness of your environment when you are growing up has a huge amount to do with how your brain develops. So you raise this inbred animal, I mean seriously, like French royalty (joking), in an empty box, and then make inferences not just about what wild mice are like, and how their brains work, but what humans are like.”

So Cook’s method is natural, non-invasive, and one would add, only a brief detour in that sea lion’s rescue by the Marine Mammal Center.  The brain damage has already occurred. Cook studies its impact in wild animals whose behaviors developed in the vastly stimulating, richly-diverse environment of the wild. Naturalistic studies like Cook’s are not going to replace the dominant lab-based studies anytime soon and there are difficulties specific to this approach, but it’s an important alternative that is starting to be explored.  And right now, for Cook and the sea lions, it’s definitely a win-win scenario: the sea lion gets to be rescued, nursed back to health, then does a stint at “Club Cook” – large circular pool, no predator threats, ample supply of anchovies. After several weeks of puzzling games involving fish, buckets, and opposing doors, off he goes, back in the Pacific.

In addition to deepening our knowledge of how the brain works and how memory damage affects behavior, Cook’s research has had immediate benefits for the animals he’s studying. Hundreds of sea lions are stranded or are in need of rehabilitation each year because of naturally-occurring brain damage and memory deficits due to domoic acid. Better understanding these effects helps veterinarians and conservation professionals make decisions about their treatment and release.

When he first started working with sea lions one of the things that surprised Cook most was what agile climbers sea lions were on land. “I had to change all my experimental stuff. I’d make the maze this high off the ground, you know like, ‘a sea lion can’t climb that!’ And they’d be like literally running around on the top of it like a bird on wire. And I was like, ‘How are you doing that?’ I had to make everything higher. And then I’d get a better climber. It was like an arms race! And the pups were very small, maybe two feet tall and they could climb up to four feet! What they do is stand on those wriggling looking hind feet and then they whip their front flippers up like they are doing a breast stroke and catch on to whatever they are climbing and these muscles are so powerful that ‘zip’ they are up and running around.”  Indeed when I visit Cook’s T-maze, I note where additional planks of wood have been bolted to the sides to make the walls higher.

Ronan leaps out of the water with another splash, her sleek fur and shiny skin belying the powerful shoulder armature beneath. This time I can see how in a split second she wedges her fins at the edge of the pool and thrusts herself out with a quick push up.  Her long thick whiskers punctuate her bright-eyed countenance. I’m totally envious. Oh, to be so amphibious, comfortable in both realms. And so peppy and strikingly alert on top it. I imagine Peet’s Coffee concocting some turbo-charged brew called “Ronan’s Blend.”

Cook gives her a command to go back in the water and then float next to the edge of the pool.  He strokes her back and strong, wide-palmed fins. “Here, put your hand on her belly,” Cook says quietly, “firmly so you don’t startle her.” Even though the water is a chilly 50 degrees, Ronan’s sleek coat is soft and warm. I notice small mammal-like claws on her rear flippers. I feel her heart beating.

Driving the coast road north that evening, with the Pacific to my left, the water doesn’t look the same. I imagine the thousands of sea lions and seals and walruses out there and how through their uniquely adapted senses they navigate the waters, hearing things as far as a mile away, foraging in near dark waters, sensing the wake of a predator nearby or fish to feed on with their elongated whiskers.  There’s so much to know, but awe isn’t a bad place to start, nor the feeling of communion, that sense of sharing a world with creatures whose remarkable sensibilities happily still exceed our imagination.



1 Comment

  1. Nicely done, Liz. The article, ie. blog, is written in a very descriptive and flowing style which is easy on these tired eyes. I especially like Ronan as a pup.
    BTW, I proudly want to mention my 40 year old son David who is a regular volunteer at the Marine Mammal Rescue Center in Marin. Good to know that some of his Dad’s influence rubbed off. Or might it be genetic vs environmental?


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