It was the days of the Mexican revolution and Juan Cuevas had had enough. La Paz had grown too big and too political for his tastes so he set out to find someplace with no government and no people. A Sea of Cortez fisherman by trade, Juan tried living on the beautiful and unpopulated islands of San Jose and San Francisco; these experiences prompted him to add no mosquitos and no noseeums to his list of requirements. After years of defining his search by what he didn’t want, in 1923 he finally found what he did: El Pardito, a 2.5 acre rock in the Sea of Cortez, 45 miles north of La Paz. There were no structures, no gardens, no electricity, no people, no government, no mosquitos. It was just a rock, and Juan was thrilled. He brought his wife Paula out to El Pardito and in short order they built a wooden house, brought in chickens and pigs and produced 9 children. From that day to this, a Juan Cuevas has lived, worked and loved on El Pardito.
El Pardito. Photo by Carlos Gajon
When Juan found his dream location it was still almost two decades before Jacques Cousteau would declare the Sea of Cortez the Aquarium of World due to its great abundance of marine life. A fisherman living on a rock in the midst of such bounty smacked of genius, and Jacques Cousteau himself once paid Juan a visit on his rock. “Most fishing communities in the days of the original Juan focused on shark fishing as shark livers were the main source of Vitamin B around the world until other sources emerged during World War II. Demand was huge and the original Juan was a big part of this trade” notes Amy Hudson Weaver, a marine biologist with the conservation group Niparajá who lived on El Pardito for 8 months in 1995-1996 and continues to work closely with the family. “Juan was so successful that he was able to build a large house for the family on the Malecon in La Paz so they would have a place to stay during their periodic trips to the city.”
Wealth was not all that the Cuevas family accumulated. Notes Amy, “To successfully hunt sharks you have to know a tremendous amount about them. For example, you have to know when they are pupping so you don’t accidentally interfere with reproduction. That knowledge was handed down among the generations in the Cuevas family, and many shark biologists spend time at El Pardito because the family’s knowledge of sharks is so deep.”
Sharks are just one of myriad species for which the Cuevas family has profound knowledge. Don Croll, the former director of the School for Field Studies and current professor at the University of California at Santa Cruz, has been going to El Pardito for 30 years, and has known the current Juan Cuevas, the 40-year old great great grandson of the original since he was 10 years old. “Juan and his brother Felipe didn’t have much formal education on El Pardito, but their knowledge is astounding. Lots of people can identify a turtle or fish species when they’re holding it in their hands, but Juan and Felipe can identify a species from the boat from really far away, and I rely on them for this. Their marine life capture skills are equally remarkable. When the Monterrey Bay Aquarium needed someone to help them live capture manta rays for their Sea of Cortez display, I didn’t hesitate to recommend Juan and Felipe.”
Luli Martinez with Juan and Felipe Cuevas. Photo by Luli Martinez
By the time Don’s doctoral student, Luli Martinez, started field work for her Ph.D. on El Pardito in 2014, the great abundance of the Sea of Cortez was a thing of the past. Notes Luli, “The 1970s to 1990s saw the highest use of resources, and sea turtle, shark and other marine life populations began collapsing. When I first started hiring Juan and Felipe to assist me with my conservation research, they were very passionate about marine species but conservation was not where their hearts were at. Then something happened that really changed their perspective. They were helping Don research a manta ray nursery in the mangroves of Isla San Jose when they discovered a population of hawksbill turtles. The Eastern Pacific population of hawksbills is the most endangered hawksbill population in the world, so this was really an important discovery. Hawksbills are not killed for their meat – they’re really not that tasty – but rather for their shells, which are used to make jewelry, and their skin, which is used to make leather goods. In the course of our research on this population Juan and Felipe really took note of the individual turtles, naming them and getting inside their personalities. They developed a sense of belonging to the hawksbill turtles. Now they are not just working for me for a paycheck, we are a team together. They now physically protect the estuary and mangroves of Isla San Jose. They quit fishing in the estuary to recover the population of commercial fish species, and they are proud because the fishing ban protects the turtles too.”
Juan Cuevas tagging and releasing a Hawksbill turtle. Photo by Luli Martinez
Says Juan, “All of us on El Pardito used to be the enemies of conservation. But now years of working with Don, Amy, and Luli has really changed our perspective. We no longer have the luxury of the previous generations of fishermen to catch everything without a thought. We now need to give back to the ocean. We don’t use nets anymore and we’re trying to spread artisanal, hook and line fishing throughout the community. Change requires a lot of patience, diligence and effort, and we’re committed to that. Now 70% of our income comes from conservation work and only 30% from fishing.” Now, rather than catching and killing sharks for the market as the original Juan did, Juan and Felipe use their deep knowledge of sharks and mad freediving skills to tag sharks for researchers like Dr. James Ketchum of Pelagios Kakunjá who is working to protect and recover shark species in the Sea of Cortez.
Estuary of Isla San Jose. Photo by Miguel Angel Aguilar Juarez of Rutafilms
Stephanie Rousso, a marine ecologist who works with Juan and Felipe notes just how far the El Pardito community has come in its relationship to the sea. “El Pardito forms part of the first ever multi-species Fisheries Improvement Project (FIP) initiated by Niparajá and ProNatura to create a system of fish refuge zones for monitoring improvements in fish populations. This FIP was started in 2017 to monitor 33 main species. Participating fishers harvest these species using the more traditional, more sustainable method of hook and line. It is wonderful to see the current generation of fishers in their 30s to 40’s working to replenish the fish stocks and help revive populations overfished by previous generations.”
Says Luli, “The success of my hawksbill project is due to the El Pardito community. When I’m invited to give talks in Mexico City by groups like the WWF I take Juan and Felipe with me, and of course the audience loves them much more than me! They are now so well respected by other conservation researchers and they are increasingly in demand.”
Juan and Felipe Cuevas speaking at a WWF event in Mexico City with Luli Martinez. Photo by Alianza WWF Fundación Telmex Telcel
“In demand” seems to be a theme for the Cuevas family. The original Juan might have wanted to get away from crowds, but it seems he was still a social guy. Family lore posits that he had several “wives” in different ports, all of whom produced a good number of offspring. He also developed a strong connection with the community of Las Animas in the mountains of Baja Sur. Amy shares some of the family history she picked up during her 8 months of living on El Pardito. “The Cuevas family needed these large steel hooks for hunting sharks, so they would trade shark, fish and turtle meat with the blacksmith artisans of Las Animas who produced them. When the Las Animas guys were ready to trade, they’d go to the beach closest to El Pardito, light a bonfire to signal the family, then the whole community would sail over. Great parties would ensue on the beach, and this is how El Partido got not only steel hooks, but fresh fruit, vegetables and meats. The ranches in the Sierras were also where the younger generations of Cuevas men would go to find wives. They would sail across to the mainland from El Pardito, hike into the Sierras, then stay for a couple of weeks on the ranches while they courted their sweethearts. This was a very successful strategy.”
El Pardito. Photo by Miguel Angel Aguilar Juarez of Rutafilms
Living on a small rock with the Cuevas family might not seem compelling to all but it appears to be irresistable to most who get the opportunity. Recalls Don, “An American couple, Jaime and Heidi Schultz, were boating near El Pardito in 1976 when they got into trouble. The Cuevas family rescued them and sheltered them on the island. The Schultz’s loved the family and El Pardito so much that they built their own house on the island, and would come down for extended periods every year.” Don, Amy and Luli all understand the pull. “The Cuevas family is my family. My kids have grown up with their kids,” says Don who still brings groups of students to the island every year. “Juan and Felipe are like my brothers” says Luli. “They are my family.” Amy is all in too. “El Pardito is one of my favorite places in the world. I love this family.”
Juan is open to seeing you too. “We are available to anyone who wants to know how to survive in the world. Today so many people live in their phones, not in the world. We have a lot of things to teach people about how to survive outside a city, so please leave your phone at home and come visit us.” The original crowd-shunning, people-embracing Juan couldn’t have issued a better invitation himself.
Swimming with the sea lion puppies at Los Islotes, the southernmost rookery of the California Sea Lion, Zalophus californianus, is truly one of life’s great joys. The puppies are often playful and naughty, nibbling on the flippers and fingers of human visitors, while their teenage siblings like to sidle up to humans for a good belly rub or game of chase. Their mothers may be found sunning themselves on the rocks, enjoying a snooze, while the males who rule the 20 territories of Los Islotes indefatigably patrol the waters to ensure everyone’s safety. It is a scene of utter Baja bliss, and humans can’t help but feel a magical glow from this most wondrous of wildlife encounters.
All of which begs the obvious question: Why are the males working so hard when everyone else is just having a good time?
Claudia J. Hernandez-Camacho, a professor of biology at CICIMAR in La Paz, has been studying the sea lions of Los Islotes and the Sea of Cortez since 1990. In particular, she has studied the entire lifespan of 190 sea lion individuals (94 females, 96 males) who were hot-branded by her professor between 1980 and 1984. Her findings, based on these specific sea lions and others, tell a complicated tale for our pinniped friends.
“Sea lions are polygynous, meaning that one male mates with several females in the territory that he defends on land and sea. It takes an enormous amount of energy to defend this territory, and in the breeding season a territorial male, who is so focused on his job that he barely eats or sleeps, can lose up to 30% of his impressive body weight (400 to 500 kilos, or about a ton) in just a few weeks.”
Photo by Colin Ruggiero for Todos Santos Eco Adventures
One would assume, of course, that the males are spending this incredible amount of energy to defend their harems and offspring, to ensure the survival of their genes. “But this is not exactly the case” says Claudia, “they are defending the territory, not the females.” The science proves this out. “Genetic studies show that just 15% of territorial males are the fathers of the newborns the next breeding season. It is not just that the females hook up with and get impregnated by wandering, opportunistic males when they slip off for their 4-5 day feeding trips, which they do, but in some cases the territorial males are not even copulating with the females in their territory.” All that work and no sex?
“It’s a little more complicated than that,” says Claudia. “There are 600 individual sea lions at Los Islotes, and every year around 170 pups are born. Almost 30% of the pups die in the first two years, either from disease or because they or their mothers have fallen prey to predators. But that means that 70% are surviving. With this type of situation, many of the sea lions are, by definition, related. It could be argued that the Los Islotes males work so hard not just for their own offspring, but because they are protecting their extended families. This would also explain why they do not copulate with all the females in their territory. They are avoiding inbreeding.” This is an approach to collective living that we generally only associate with high intelligence mammals like primates, elephants and dolphins.
The Los Islotes territorial males are so successful in their defense of the colony, and have made conditions so conducive to survival, that Los Islotes is actually full to capacity now. In fact, two new satellite colonies have been created nearby in recent years by all the young males who are no longer welcome at Los Islotes, but who are still too young and slight to fight older, larger males for territory. Sea lions are philopatric, meaning that they stay in or habitually return to the area of their birth, so it is possible that these satellite colonies will only continue to grow.
What makes this all the more remarkable is that it is happening at a time when the overall population of California Sea Lions in the Sea of Cortez is dropping dramatically. Between 2000 and 2018, 40% of the population of other colonies disappeared. Are those males falling down on the job? Not likely says Claudia. “We are analyzing a lot of
Photo by Colin Ruggiero for Todos Santos Eco Adventures
environmental variables right now to determine the main factor causing the decline of these colonies, but one of the most likely culprits is the food supply” she observes. “It is not that the fish populations in the other parts of the Sea of Cortez are declining, they are not. It is that the fish are moving further south. While the sea lions of Los Islotes, the southernmost California Sea Lion rookery, are benefitting from this trend, it is proving lethal to others. Healthy females will travel up to 60 kilometers away from their colonies to find food, but further than that is not feasible. They need to conserve energy to produce milk for their pups. And even in those more northern locations where there are still fish, there are a very limited number of fish species, and this relatively poor-quality diet means that the females are not gaining enough energy from their food to productively nurse their pups. On the opposite side of the coin, the sea lions of Los Islotes are getting an increasing number of fish species in their diet, with the result that population density has reached an all-time high.”
Female sea lions are not only philopatric, i.e., prone to stay in the area where they were born, they are attached to very specific real estate in that area, with many staking one specific rocky outcropping for their own. So with the increasing density of the population at Los Islotes, it is not surprising to learn that sea lion attitudes are becoming a bit more aggressive. Add to that the fact that the entire colony of females either a) goes into estrus, or b) has newborn pups to defend at exactly the same time and breeding season, which generally takes place June 1 to August 31, becomes a time when human body parts might best be kept at a distance from the sea lions of Los Islotes. In fact, Los Islotes is now closed to snorkelers and scuba divers during this period.
Los Islotes is regularly listed as one of the top diving/snorkeling spots in the world, and Claudia and her students are launching a study to evaluate the effects of all these visitors on the sea lions. The tourism hiatus being imposed by the authorities during breeding season offers them the perfect opportunity for their research. “We have already collected fecal samples from the sea lions during the tourist season, and will now do so again when the colony is closed to tourists. We will then test the level of cortisol, a stress indicator, in both sets of fecal matter to determine if tourism increases stress in sea lions. We have already observed some differences in behavior in the sea lions at Los Islotes. While at other, more remote colonies, the sea lions will copulate during the day, at Los Islotes they only engage in this behavior at night. We hope to be able to determine if tourism is having an impact on the sea lions.”
Claudia at Los Islotes
Of course, liking your loving in the evening time is a common enough attribute of many healthy mammals, but if other colonies are also enjoying some afternoon delight, have the sea lions of Los Islotes gone too far in adapting to the presence of humans? Will the territorial males one day snap back to impose a more natural environment for their territories? Human males have certainly done battle over lesser issues.
Tourists have been visiting Los Islotes on a regular basis for roughly three decades, and sea lion males live an average of 19 years. There is therefore not yet a deep institutional knowledge about humans among the territorial males, and they could still be giving us the opportunity to demonstrate our worthiness as visitors to their home. Will we make the cut? We can’t be sure what the sea lions have learned about humans over the years, or what Claudia and her team will demonstrate, but the strong pull of Los Islotes on humans is easy enough to understand: it is a place where joy and spontaneity rule, and we thrill to that vibrancy. While the territorial males are likely not motivated by their roles as life coaches for humans, it is enticing to think that maybe just one of the reasons they work so hard is to protect such a joyful lifestyle for their families. Claudia and her team are working hard to do the same.
VISIT WITH CLAUDIA AND HER TEAM!
Todos Santos Eco Adventures is the leading eco adventure company in Baja California Sur. On Isla Espiritu Santo we operate Camp Cecil, a luxury tent camp, and Camp Colossus, a moveable glamping operation. Claudia and her students will be spending time with us at our camps throughout the season as they conduct their sea lion research, so you may find them at the dinner table if you spend time with us at the island!
Blue-footed Boobies at Isla La Gaviota in the Sea of Cortez. Photo by Colin Ruggiero
At a time when over half the single people in the Americas have created an online dating profile through which they send out their virtual avatars to court potential partners, it may be difficult to remember the days of Saturday Night Fever and Strictly Ballroom when plumage and dance moves were everything. But off the coast of Baja California Sur on islands like La Gaviota, Isla Isabel, and Isla San Pedro Mártir, dancing to show off mating suitability is alive and well, although the practitioners looked so silly to early outside observers that they earned themselves the name of Booby, from the Spanish word bobo meaning “stupid” or “clown”. Pretty much your worst dancing-in-public nightmare.
But the Blue-footed Boobies of Baja remain unruffled, secure in the knowledge that shaking their tail feathers has resulted in what is possibly the largest Blue-footed Booby colony in the world. And it’s not just the moves that are important in their dance, but the exact cerulean hue the footwork displays. Blue-footedness, it turns out, is enhanced by the bright yellow pigments found in the carotenoids of the fish the birds consume, so those who catch and eat more fish get bluer feet. Ipso facto bluer feet connote better health, better health connotes greater ability to provide for a nest, and as every dancer in life thinking about raising a chick knows, those are the moves that really count in a mate. So the booby dance includes a series of steps in which the feet are raised up to allow potential partners to inspect their blue-ness (apparently a vibrant aquamarine is the most desirable) and determine if that’s the blue they want to get tangled up in. And unlike in some species in which only the male sports the color, in boobies both sexes are focused on the blue tones of a potential partner’s feet. In fact, males will avoid mating with females whose blue feet have been dulled with paint. With boobies, it definitely takes two to tango.
Blue-footed Boobies. Photo by Colin Ruggiero
And in many cases, three. Researchers have found that Blue-footed Booby rookeries could easily provide source material for the most salacious telenovelas; in over 50% of booby couples one or both partners engage in what scientists call extrapair behavior (what the rest of us would call an extramarital affair), and it is not at all uncommon for a booby to toddle off for a quickie with the neighbor while its mate is out foraging at sea. Dr. Hugh Drummond, Professor of Biology at the National Autonomous University of Mexico (UNAM), who has studied the Blue-footed Boobies at Isla Isabel for the last 37 years, notes his education on this point. “There was a time when we thought that all bird species were monogamous and mated for life. This couldn’t be further from the truth. The majority of studies indicate extra pair behavior in birds. This is not surprising in males as this behavior can provide them with extra offspring at no cost. What is surprising is that in the vast majority of bird species, including the Blue-footed Booby, the females stray. It’s surprising because this behavior can be accompanied by some fairly high costs.”
Scientists, being scientists, have been searching for a rationale for the female booby’s lustful leanings as “because she can” doesn’t square in a world in which behaviors are generally explained by survival and advancement of the gene pool. The working hypothesis was that a female who is nest hopping with the neighbors must be doing so because she is not paired with the ideal biological partner, and is therefore driven to hook up with a better set of genes. But, as Dr. Drummond notes, “Most studies have found no difference in the success of the mated pair’s offspring versus the success of the extra pair’s offspring. The extra pair males have not consistently proven to provide better genes than those of the mates. So we have to consider that the female’s behavior may not be for the benefit of the offspring after all.” Have female boobies liberated themselves from the Darwinian grind?
Blue-footed Booby in the Sea of Cortez. Photo by Colin Ruggiero
Possibly, but the males aren’t taking it lying down. They will destroy an egg in their nest if they suspect it was fertilized by another, and if the female was out of their observation range for a few hours or more during the 5 days of fertility prior to egg laying, then they are definitely suspicious. Dr. Drummond and his colleagues tested this by “kidnapping” males during the 5 critical days. Under these circumstances, the males destroyed the first egg subsequently laid, ensuring that they didn’t have to raise some other guy’s chick. If they are kidnapped prior to the fertile period they leave the egg alone. Male boobies will actually abandon particularly perfidious partners, and seek out others to soothe their ruffled feathers. Says Dr. Drummond, “Isla Isabel has roughly 2,000 pairs of Blue-footed Boobies, and at the end of every season half of the pairs break up.”
Before egg incubation starts, nearly all male boobies on Isla Isabel court extra pair females, while roughly one third of the females develop sexual relationships with one or more male neighbors. But booby mates who retain the same partner for successive years definitely reap gene pool rewards – Dr. Drummond has found that they produce 35% more offspring those who change partners. And while all booby couples share in parental duties, longtime mates spend equal time caring for their young. They are completely in it together, with males spending just as much time as their mates on household duties. Female boobies. Has their behavioral long game all along been shaping male boobies into the perfect domestic partner? That would be a remarkable evolutionary feat!
While longtime mates may cohabit harmoniously, harmony is definitely not a word one would associate with their offspring in the nest. Dr. Dave Anderson, Professor of Biology at Wake Forest University, has studied boobies in the Galapagos Islands for most of his adult life. He explains. “Nazca boobies (the Blue-foot’s cousin) only want one chick but they sometimes have two by mistake when their extra insurance egg hatches. In such cases, 100% of the time the older (or healthier) chick will force the other one out of the nest with no parental interference, and perhaps even some parental facilitation. Once out of the nest, a chick has no way to survive on its own. Nazca boobies nest on the ground in such a way that the nest is essentially a gladiatorial arena that the parents observe from on high.”
“The Blue-footed Boobies, on the other hand, do want the option of having two chicks. So they will give the first egg a head start of 3-5 days before laying the second egg, such that a natural dominance hierarchy is established among the resulting chicks. If food is abundant, they will raise both chicks. However, the first-hatched chick fiercely beats up the second-hatched, and the second-hatched survives only by adopting submissive behavior.” Dr. Anderson points out that the parents help the subordinate by building nests that are bowl-shaped, which means that when the older chick is pecking the younger one, at least for the first ten days or so, the poor little guy generally doesn’t fall out of the nest like its hapless Nazca counterpart – there are walls to keep it hemmed in. Further, unlike the murder-permissive Nazcas, murder-restrictive Blue-footed Booby parents will actually sit on their chicks to prevent the dominant from killing the subordinate.
Dr. Anderson tested what would happen when the constraints of the parents and the bowl-shaped nest are removed. “What is really interesting,” says Dr. Anderson, “is when we put Blue-footed Booby chicks in Nazca nests with Nazca parents. They are much more aggressive than when in their own nests. And when we put Nazca chicks in Blue-footed nests with Blue-footed parents, they still want to kill each other but can’t because of the shape of the nest and the murder-restrictive Blue-footed parents.” They may fool around like mad, but the Blue-footed Boobies do draw the line at siblicide, unless of course, food is scarce – as in an El Niño year – and subordinate chick sacrifices must be made.
Blue-footed Boobies. Photo by Colin Ruggiero
Now you may well imagine that the poor second-hatch chicks, having been so horribly abused by their siblings and practically starved to boot, would turn into physically stunted adults, emotionally crippled by their circumstances and consigned to a lifetime of failure. “Not so!” says Dr. Drummond. “We compared 1,167 fledglings of two-chick broods for 10 years and found few differences between first-hatched and second-hatched birds. Even more surprisingly, where there were differences these tended to favor subordinates.” By almost every measure that counts in a booby’s biological life, Dr. Drummond found that the subordinate chicks matched or bettered those of their dominant tormenters including survival, defensive ability, brood size, nest success, and cumulative brood size over the first ten years of life. Blue-footed Boobies. Liberated females, progressive males, bullies not allowed to flourish over others. What else can we learn from our blue-footed friends?
Every mating season the Blue-footed Booby males stake out their territories and wait for females to come by and notice them. “The males then fall all over themselves trying to demonstrate their suitability as a mate” says Dr. Drummond. One would think in such circumstances that younger, more virile (and of course bluer-footed) birds, would rule the day. But once again, things are not always as one would imagine in the booby world. Dr. Drummond and his colleagues have found that May-December romances among the boobies, i.e., partnerships in which one bird is old and one bird is young, produce offspring that are significantly more likely to later become parents themselves compared to the offspring of parents of a similar age. And it doesn’t seem to matter which sex is at which end of the age spectrum, old mothers and young fathers or old fathers and young mothers, the results were the same in the 3,361 booby offspring that Dr. Drummond and his colleagues studied – breeding in age-mismatched parents provides greater success in contributions to the gene pool than those of similarly aged parents. In fact, the advantage to the chicks born of May-December parents was almost as great as those conferred on chicks whose parents are in long-term partnerships. Why this is so remains a scientific mystery. Could it simply be that Blue-footed Boobies are as socially evolved as the French?
So now we know that these dancers who looked so silly they earned themselves the name of Booby may actually have some elegant lessons to share across species: 1. A rough start in life need not define your later years; 2. Sharing equally with a long-term partner produces better health for the family; 3. Age does not necessarily define your ability to contribute to society; and 4. Dancing your heart out no matter what you look like to strangers is one of the keys to a successful life. In fact, the future of the species depends on it.
