The Magic, Wonder, and Science of Ocean Bioluminescence in Southern California

How and why so many of earth’s creatures make their own light.

Bioluminescent waves in Southern California

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Last month, a video went viral showing a small pod of dolphins swimming at night off the coast of Newport Beach. Seeing dolphins off Southern California is not particularly unusual, but this was a very special moment. In the video, the dolphins appear to be swimming through liquid light, their torpedo-shaped bodies generating an ethereal blue glow like a scene straight out of Avatar. The phenomenon that causes the blue glow has been known for centuries, but that in no way detracts from its wonder and beauty. The phenomenon is called bioluminescence, and it is one of nature’s most magical and interesting phenomena.

A Caridean shrimp, *Parapandalus* sp., enveloped in bioluminescent spew emitted during an escape response. *(NOAA/OER)*

Bioluminescence is the production and emission of light by a living organism, and it is truly one of the great magical properties of nature. At its core, bioluminescence is the way animals can visually sense the world around them. It’s all built on vision, one of the most fascinating and useful senses in the animal kingdom. Seeing is impossible without light, and so it makes sense that in the absence of sunlight, some animals created a way to make their own light.

I have been fascinated by bioluminescence since I was a child growing up near Newport Beach when the occasional nearshore red tide bloom would illuminate the waves like a high tech LED light show. It’s a truly magical experience. I’ve also experienced bioluminescence in various places around the world, including Thailand, Mexico, and Puerto Rico. In fact, 13 years ago, I made the trip to Puerto Rico’s Vieques Island and its world-famous Mosquito Bay, for the sole purpose of seeing the bay in person and swimming and kayaking in its warm, glowing waters (there is a rental outfit there that does tours at night…it’s amazing. Trust me.)

The phenomenon of bioluminescence is surprisingly common in nature. Both terrestrial and sea animals do it, as do plants, insects (for example, fireflies), and fungi. Curiously, no mammals bioluminesce. That we know of, although several species fluoresce, which is when organisms absorb light at one wavelength and emit it at another, often under ultraviolet (UV) light. The platypus is an example. But the ocean is definitely the place that animals and plants bioluminesce the most. Which makes sense because deep in the ocean, there is little or no light. Light is absorbed very quickly in the water, so while on land you might be able to see a single streetlight miles away, after about 800 feet, light largely disappears in the depths of the ocean. I know. I’ve been there.

It’s estimated that nearly 90 percent of the animals living in the open ocean, in waters below 1,500 feet, make their own light. Why they do this is in part a mystery, but scientists are pretty sure they understand the basic reasons animals do it: to eat, to not be eaten, and to mate. In other words, to survive. And to communicate.

The angler fish dangles a lighted lure in front of its face to attract prey. Some squid expel bioluminescent liquid, rather than ink, to confuse their predators. A few shrimp do too. Worms and small crustaceans use bioluminescence to attract mates. When it is attacked, the Atolla jellyfish (Atolla wyvillei) broadcasts a vivid, circular display of bioluminescent light, which scientists believe may be a kind of alarm system. The theory is that the light will attract a larger predator to go after whatever is attacking the jellyfish. While this is still a theory, a 2019 expedition that took the very first images of the giant squid used a fake Atolla jellyfish designed by the scientist Edith Widder to lure the squid into frame. I had the fortune of interviewing Dr. Widder, one of the world’s top experts on bioluminescence, several years ago for the New York Times.

Edith Widder holds a vial of bioluminescent plankton. Credit: Erik Olsen

Making light is clearly beneficial. That’s why, say evolutionary biologists, it appears that bioluminescence has arisen over forty separate times in evolutionary history. The process is called convergent evolution and is the same reason that bats and birds and insects all evolved to fly independently. Clearly, flying confers a major advantage. So does making light.

While the Internet is awash in images of bioluminescent creatures, very often the term is confused with fluorescence (mentioned above). Even reputable science organizations sometimes do this. Bioluminescence is not the same thing as fluorescence. Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. Many animals like scorpions and coral fluoresce, meaning that they appear to glow a bright otherworldly color when blue light is shone on them. The key idea here is that the animals are not generating their own light, but rather contain cells that reflect light in fluorescence.

Fluorescent (not bioluminescent) scorpion in Baja California, Mexico. Credit: Erik Olsen

So what about the recent explosion of bioluminescence in Southern California? The light we are seeing is made by tiny organisms, type of plankton called dinoflagellates (Lingulodinium polyedra) that occasionally “bloom” off-shore. Often, this is the result of recent storms that bring tons of nutrient-laden runoff into the ocean. The tiny plankton feed on nitrogen and other nutrients that enter the ocean from rivers and streams and city streets. A lot of the nutrients come from California’s vast farms, specifically the fertilizer used to grow California’s fruits and vegetables. With all that “food” coming into the ocean system, the algae rapidly multiply, creating red tides, or vast patches of ocean that turn dark brownish red, the color of pigment in the algae that helps protect it from sunlight. Michael Latz, a scientist at Scripps Institution of Oceanography at UC San Diego, says that the animals use bioluminescence as a predator avoidance behavior.

Sometimes red tides are toxic and can kill animals and make people sick who swim in the ocean. (That does not appear to be the case in California right now). At night, when they are still, the animals can’t be seen. But when the water is disturbed, which adds oxygen into the mix, a chemical reaction takes place in their bodies that causes luciferin (from the Latin lucifer or ‘light-bearer’) to oxidize and becomes catalyzed to make luciferase, which emits photons or particles of light. It’s not understood exactly how or why this happens, but we do know there are many kids of luciferase. In fact, scientists know the genes that create luciferases and have implanted them into organisms like mice, silkworms, and potatoes so that they glow. They’ve made bioluminescent plants, too. An Idaho-based start up called Light Bio, in fact, sells bioluminescent petunias that you can purchase.

Light Bio’s genetically engineered petunias glow green thanks to DNA added from bioluminescent mushrooms. Photo (Light Bio)

Perhaps the most magical thing about bioluminescence is that it doesn’t create heat. Almost all the lights we are familiar with, particularly incandescent light, like that from generic light bubs, generate a tremendous amount of heat. Of course, we have learned how to make this heatless chemical light ourselves, easily experienced when you crack and shake a glow stick, mixing together several chemicals in a process similar to the one animals in the ocean use to create bioluminescent light. But the light from glow sticks is not nearly strong enough to illuminate your back yard. In the last few decades, we’ve learned how to make another kind of light that produces little heat: LEDs. Though the process is very different, the concept is the same: talking a molecule or a material and promoting it to an excited state. Where electricity is used, in the case of LEDs, it’s called electroluminescence, where it’s a chemical reaction it’s chemiluminescence, of which bioluminescence is one form.

Whether you are a religious person or not (I’m not) it’s no coincidence that one of the first things God said was, “Let there be light!” Light and light energy give us plants and animals to eat, and allows us to see. It heats our world, it fuels our cars (oil is really just dead organic material compressed over time, and that organic material would not have existed without sunlight). While some animals deep in the ocean can live without light, most of us cannot. And it’s a rather astounding feat of nature than when there is no light, many of the earth’s creatures have evolved to produce it themselves. If you don’t believe me, just go down to the Southern California shore in the evening when there is a red tide. Leave your flashlight at home. You won’t need it.

The Lost Island of Santarosae off California’s Coast

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Imagine a massive island off the coast of California roughly thrice the size of Maui, a lush and wild place where miniature mammoths once roamed and ancient humans hunted in the shadows of towering trees. This island once existed and it’s called Santarosae, and while it is gone now, it was once a thriving ecosystem, teeming with life. Its story provides a captivating window into the ever-changing natural history of the California coast region.

During the last Ice Age, approximately 20,000 to 25,000 years ago, when sea levels were significantly lower, Santarosae Island was a single, expansive landmass that now comprises most of California’s Channel Islands. As the cooler Pleistocene climate transitioned into the warmer Holocene (the epoch we are in now), the Earth’s oceans heated and expanded. Continental ice sheets and glaciers melted, releasing vast amounts of water and causing sea levels to rise dramatically.

At its peak, Santarosae was massive—four of today’s Channel Islands (San Miguel, Santa Rosa, Santa Cruz, and Anacapa) were all connected into a single landmass. It spanned around 1,500 square miles, making it a significant feature of the Pacific coast landscape. Today, only remnants remain in the form of those four separate islands, but evidence of Santarosae’s ancient past continues to reveal itself to scientists.

Map depicting the reconstructed geography of Santarosae.

Anacapa was the first to break away, around 10,300 to 10,900 years ago, as rising waters gradually submerged the narrow isthmus that once connected it to the rest of Santarosae. This slow disintegration of the super island was witnessed by the humans already inhabiting the region. Having arrived between 12,710 and 13,010 years ago, possibly even earlier, these early settlers likely traveled by boat, following the “kelp highway“—a rich, coastal ecosystem of underwater seaweed forests stretching from northern Japan and Kamchatka, along the southern shores of Beringia, down the Pacific Northwest, and into Baja California. For these early explorers, Santarosae would have appeared as a land of abundant resources.

One of the island’s most captivating features was its population of pygmy mammoths, found exclusively on Santarosae. Standing between 4.5 to 7 feet tall at the shoulder and weighing around 2,000 pounds, these miniaturized versions of mainland Columbian mammoths were about the size of a large horse and evolved to suit their isolated island habitat (see our story on the island biogeography of the Channel Islands). The reasons for their dwarfism stem from a phenomenon called island rule, where species on islands often shrink due to limited resources and isolation, as well as a shortage of predators. Despite their smaller size, these island-dwelling mammoths likely shared many characteristics with their larger relatives, including a similar body shape, short fur, and a large head. These mammoths roamed Santarosae until they disappeared around 13,000 years ago, coinciding with both climate changes and the arrival of humans.

Pygmy Mammoth excavation on the Channel Islands (NPS)

The first discovery of “elephant” remains on Santa Rosa Island was reported in 1873. Over time, additional excavations provided insight into the island’s mammoth population, which gradually became smaller over generations, eventually disappearing at the end of the Pleistocene. Notably, paleontological digs conducted on Santa Rosa Island in 1927 and 1928 unearthed the remains of a new species, Mammuthus exilis. In the 1940s and 1950s, Philip Orr of the Santa Barbara Museum of Natural History recovered further specimens while conducting archaeological and geological work on the island.

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Most pygmy mammoth remains have been discovered on Santa Rosa and San Miguel Islands, with fewer finds from Santa Cruz Island and even fewer from San Nicolas Island, which lies outside the Channel Islands National Park.

Santarosae was not just a wilderness for megafauna—it was home to some of the earliest known human settlers in North America. Archaeological discoveries, such as the remains of a 13,000-year-old woman unearthed on Santa Rosa Island, point to a sophisticated maritime culture. These ancient humans, likely ancestors of the Chumash people, navigated the waters around Santarosae in plank canoes, hunting seals, birds, and fish, while gathering plants and shellfish.

Archaeologists excavate a anthropological site at the Channel Islands (NPS)

The island provided ample resources, but it wasn’t isolated from the rest of the world. The people of Santarosae were part of a complex trade network that stretched across the California coast. Evidence of these connections can be seen in the tools and materials found on the island, some of which came from distant sources. As sea levels rose, however, these early inhabitants had to adapt to the shrinking island, eventually migrating to the mainland.

Santarosae’s landscape during the Ice Age was strikingly different from what we see on today’s Channel Islands. Dense forests of pines, oaks, and other vegetation covered much of the island, supporting a rich diversity of life. The island’s topography included hills, valleys, and freshwater sources, offering an ideal environment for both humans and animals. As the climate warmed and sea levels rose, the island’s ecology shifted. Forests retreated, and the landscape began to resemble the wind-swept, scrubby terrain seen on the modern Channel Islands.

The rise in sea levels didn’t just transform the landscape; it also altered the ecosystems. Many of the animals, like the pygmy mammoths, couldn’t survive the changing conditions (or human hunters), while new species adapted to the shrinking landmass. Birds, insects, and plant species began to dominate, and the island ecosystems became more specialized.

Today, the remnants of Santarosae offer an invaluable window into the past. The Channel Islands National Park protects much of the area, and researchers continue to uncover clues about the island’s history. Ongoing archaeological digs and ecological studies on the islands help piece together the story of Santarosae’s people, animals, and landscape.

Tourists now enjoy the natural beauty of the Channel Islands (Erik Olsen)

For those who visit the Channel Islands today, it’s hard to imagine the ancient world of Santarosae—a much larger island teeming with life. But the remnants of this lost island still hold secrets waiting to be uncovered, offering a fascinating glimpse into California’s distant past and a reminder of how the forces of nature continually reshape our world.

Though Santarosae is now submerged, its influence is still a significant part of California’s natural history.

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California’s Elephant Seals are the Giants of the Golden Coast

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Once teetering on the brink of extinction, the California elephant seal has made an astounding recovery thanks to stringent conservation efforts. But as you’ll read below, their recovery comes with an asterisk. These remarkable creatures, once hunted for their blubber, now thrive along California’s iconic coastline. With their distinctive trunk-like snouts and massive size (They really are huge. I’ve visited the beach near San Simeon several times to photograph them), elephant seals are an incredible sight.

Elephant seals can be seen along the California coast year-round, but specific times are better for different activities. The peak times to observe them are during their breeding season (December to March) and molting season (April to August). During these times, especially from January to March, beaches are filled with males battling for dominance and females giving birth. Outside these seasons, many seals are out at sea, but some can still be spotted during quieter months.

Even considering the animal’s unique appearance, the elephant seal is not just any ordinary seal. Its eating and mating habits are a riveting blend of deep-sea dives in pursuit of prey and intense beachfront battles for dominance during the breeding season.

The species has two main branches: the northern and southern elephant seal. The ones lolling on the California shores belong to the northern branch. Adult males can weigh as much as 2,300 kg (around 5,000 lbs) and can reach up to 14 feet in length. Females, though smaller, play a pivotal role in the seal’s lifecycle.

Elephant seals are deep-sea aficionados, embarking on two major foraging trips each year. To fuel the intense energy demands of mating season, they dive to impressive depths, often around 1,700 feet (518 m), but have been recorded reaching as deep as 5,015 feet (1,529 m). These long dives, sometimes lasting over an hour, help them hunt squids and fishes while also avoiding predators like great white sharks. Only sperm whales dive deeper and longer, showcasing the elephant seal’s mastery of the deep ocean.

The mating habits of the California elephant seal are a spectacle, a mix between The Biggest Loser and UFC. In wintertime, the beaches teem with activity. The males arrive first, establishing territories and preparing to woo potential mates. Skirmishes between rival males are like mixed martial arts battles between extreme heavyweights (ok, I’ll stop). As they fight for dominance and the right to mate, the elephant seal mating ritual can be quite intense. They engage in ferocious body slam battles, using their massive bodies and long proboscises to assert their strength. These skirmishes, often leading to visible scars and wounds, as well as broken bones, are all for the right to mate. The victor, having established his dominance, can then secure a harem of females, while the less dominant males must wait their turn or go without. This intense ritual underscores the seal’s primal drive to ensure its lineage in the face of fierce competition.

Mating battles between elephant seals can be brutal. Photo: NOAA

A 2023 study published in the Royal Society Open Science showed that the mating battles take their toll on the animals, revealing that males with large harems who fought the most, also lived markedly shorter lives.

By the end of the season, successful males might have a harem of up to 50 females. After the mating rituals, females give birth to pups from the previous year’s mating season. The shores become dotted with adorable seal pups, drawing gawkers and photographers from around the globe.

Elephant seal near San Simeon, California. Photo: National Park Service

To catch a glimpse of these magnificent creatures, the California coastline offers several attractive vantage points. Popular spots include Año Nuevo State Park, Point Reyes National Seashore, and Piedras Blancas near San Simeon. Further offshore, the Channel Islands serve as a remote sanctuary for these seals, away from the bustling mainland. Specifically, San Miguel Island and Santa Rosa Island, both part of the Channel Islands National Park, are known hotspots for elephant seal rookeries. These islands provide remote and undisturbed habitats, making them ideal locations for elephant seals to mate, give birth, and molt.

Elephant seal rookery at Piedras Blancas near San Simeon

The elephant seal, despite its impressive size and strength, is not exempt from the challenges of predation. Great white sharks and orcas, or killer whales, are the primary natural predators of the elephant seal. While younger seals and females are more vulnerable due to their smaller size, even the massive adult males are not entirely safe. Great white sharks tend to target the seals when they’re in deep waters, ambushing them from below. Orcas, on the other hand, have been known to employ strategic hunting techniques to isolate and attack seals, especially near the shorelines. Several rather astonishing videos have been captured of orcas going after elephant seals in the wild.

The threat of these apex predators plays a significant role in shaping the behaviors and migratory patterns of the elephant seal, as they navigate the perilous waters of the Pacific in search of food and safe breeding grounds.

Elephant seals are known to be migratory, traveling thousands of miles across the Pacific. After their foraging trips, they return to their natal beaches to molt, shedding and replacing their fur and the outer layer of their skin.

Elephant seals on the beach at Piedras Blancas near San Simeon. (Erik Olsen)

However, the journey of the California elephant seal hasn’t always been smooth sailing. Over the past 50 years, there have been significant fluctuations in their population. In the late 19th century, they were nearly hunted to extinction for their blubber, which was valuable in oil production. By the end of the 1800s, only a small colony of fewer than 100 seals (some place the number closer to 25) was believed to exist. But here’s where the story takes a hopeful turn. Thanks to robust conservation efforts and protective legislation, their numbers began to rebound. Today, it’s estimated that the population is around 250,000, a testament to what protective measures can achieve. That said, an unknown proportion of elephant seal populations is always at sea, making accurate assessments of total population size is difficult.

Recent research in 2024 reveals a deeper consequence of this near-extinction event. Genetic analyses show that Northern Elephant seals, while rebounding, still bear “genetic scars.” The dramatic population decline going into the 20th century led to the loss of genetic diversity, raising concerns about inbreeding and potential future vulnerabilities to environmental changes or diseases. However, despite reduced diversity, no immediate health issues have been observed in the species.

Given the many other biological and ecological riches of California (this magazine highlights many of them), the elephant seal owns a precious spot in the pantheon of California’s natural wonders. With their unique lifecycle, impressive size, and dramatic beach battles, elephant seals hold a special place alongside the state’s ancient redwoods, vast deserts, and diverse marine life. Their remarkable comeback from near extinction and the key role they play in coastal ecosystems make them a symbol of resilience and the enduring power of nature to regenerate when given the chance.

New Research Sheds Light on the Saber-Toothed Cats of California, Fierce Predators of the Pleistocene

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Around 15,000 to 20,000 years ago, the landscape near present-day Los Angeles was a diverse mix of environments shaped by the end of the Ice Age. Cooler and wetter than today, it was dominated by savannah-like grasslands, wetlands, and patches of dense forests filled with towering oaks and pines. Prehistoric rivers and lakes dotted the landscape, nourishing a rich ecosystem teeming with life. Massive herbivores like mammoths, giant ground sloths, bison, and ancient camels roamed these plains, foraging on abundant grasses and shrubs.

Among these creatures of the Pleistocene Epoch, predators like saber-toothed cats (Smilodon fatalis) ruled, using the cover of forests and brush to ambush their prey. These large cats thrived alongside other carnivores like dire wolves and American lions, each species carving out its niche. However, the landscape was in flux—warming temperatures gradually dried out the environment, increasing the frequency of wildfires and altering the balance of flora and fauna. As human populations expanded and hunted large herbivores, the delicate ecosystem began to unravel, setting the stage for the extinction of many of the region’s iconic megafauna (more on this later).

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Saber-toothed cats are some of the most iconic prehistoric predators to have roamed California. Known for their distinctive long, blade-like canine teeth, these powerful carnivores thrived during a time when much of North America was covered in ice and the landscape teemed with large herbivores. Fossils of these magnificent creatures have been found across the state, with an impressive concentration in the famous La Brea Tar Pits in Los Angeles, revealing a vast amount of details about their biology, natural history, and the world they lived in. In fact, thousands of skeletons are preserved in the Rancho La Brea Tar Pits, making it the largest and most significant site for studying saber-tooth cats and other Pleistocene-era animals.

But first, let’s clear up a few things. The terms “saber-toothed tiger” and “saber-toothed cat” are often used interchangeably, but they refer to different concepts, and the distinction is important for scientific accuracy. “Saber-toothed tiger” is a misnomer because these prehistoric animals were not true tigers, nor were they closely related to them. Instead, they belonged to a now-extinct subfamily of felines called Machairodontinae, with the most famous genus being Smilodon. Modern tigers, on the other hand, belong to the Panthera genus and are part of a completely different evolutionary line. The term “saber-toothed cat” is more accurate because it reflects the broader diversity of species in this group, not just a single “tiger-like” animal. This distinction is crucial because it prevents confusion in understanding the evolutionary history of felines and avoids spreading inaccuracies in the scientific and popular understanding of extinct species.

A great deal of modern research has been conducted on the saber-tooth cat, ranging from genetic studies to isotopic analysis, fossil reconstruction, and insights into their ecological role during the Pleistocene Epoch. In fact, in 2020 researchers from the University of Copenhagen mapped the entire nuclear genome of a sabre-toothed cat known as Homotherium. The genetic study revealed new insights about a socially intelligent pack animal, that specialized in endurance-based hunting over long distances.

The cover of the 1908 October issue of *Sunset* magazine.

When you look at the fossilized skeletons of saber-toothed cats on display at the La Brea Tar Pits, it’s easy to imagine these powerful predators silently stalking their prey through the ancient landscapes, ready to spring with sharp, curved teeth bared and bloody from an earlier meal. Their upper canine teeth were long, sharp, and curved like sabers, often reaching lengths of up to 7 inches (18 cm). Unlike the teeth of modern big cats, which are built for biting and holding prey, the saber teeth were relatively fragile and not ideal for crushing bones. This suggests that these animals had to be precise in how they used their teeth to kill.

Saber toothed cat skull at La Brea Tar Pits (Erik Olsen)

Rather than relying on brute force to clamp down on their prey, saber-toothed cats likely used their teeth to deliver deep, slashing wounds to vulnerable areas, such as the neck, throat, or belly of large herbivores. Some scientists believe that after overpowering their prey with their strong forelimbs, they would deliver a quick, lethal bite, severing major blood vessels or the windpipe. The killing technique of saber-toothed cats was likely specialized for large, slow-moving prey like bison, mammoths, or camels.

Saber-toothed cat (*Smilodon fatalis*). (Indiana State Museum)

This precision style of hunting contrasts with how modern big cats, like lions, use their teeth to bite and hold, crushing the windpipe or suffocating their prey. The saber-toothed cat’s teeth were well-adapted to slicing, but not to the prolonged grip needed for suffocation.

A recent study on saber-toothed cats from paleontologist Jack Tseng of the University of California, Berkeley, reveals that juvenile cats retained their baby teeth alongside their developing adult fangs, likely as a stabilizing mechanism. This double-fanged stage, lasting up to 30 months, helped protect the growing sabers from breaking as young cats learned to hunt. Through computer simulations and mechanical tests, researchers demonstrated that the baby tooth acted as a buttress, reducing the risk of saber damage during this critical learning phase. This finding offers new insights into the hunting development of these prehistoric predators.

The cranium of a *Smilodon* with fully-erupted sabers (Jack Tseng)

Modern research is uncovering potential new insights into the saber-tooth cat’s behavior, including possible hunting techniques, social structures, and interactions with other species. Paleontologists have found fossilized throat bones in Smilodon at the La Brea Tar Pits similar to those in modern big cats like lions and tigers, suggesting that these prehistoric predators may have also roared with powerful vocalizations.

One of the most fascinating debates surrounding Smilodon is whether they hunted alone or in groups. Further fossil evidence from the La Brea Tar Pits suggests that these cats may have lived and hunted in social groups, similar to modern lions. Many Smilodon skeletons show evidence of healed injuries, which has led paleontologists to believe that they may have cared for each other in social settings, allowing injured individuals to recover rather than being abandoned. This level of social cooperation would have been an important adaptation in a world full of dangerous megafauna, enabling them to take down larger prey.

Prehistoric scene with saber-toothed cat.

The extinction of saber-toothed cats, specifically Smilodon, in California has been a subject of extensive research. A study from 2023 published in the prestigious journal Science shows just how quickly the largest animals disappeared from the La Brea fossil record. Scientists from the La Brea Tar Pits, including a University of Oregon professor and postdoctoral researcher, employed a computer model to explore how factors like wildfires, climate change, species loss, and human presence interacted. This revealed a far more intricate explanation for the extinctions than earlier theories, which often pinned the blame on a single factor such as human overhunting or climate shifts. According to the study, humans likely played a pivotal role by driving herbivores to extinction, which in turn led to an overgrowth of vegetation, creating fuel for wildfires. At the same time, the climate was becoming drier, compounding the problem, and leaving carnivores without sufficient prey to survive.

**Sequence of ecological events as recorded at Rancho La Brea, California.** (Natural History Museum of Los Angeles County)

Although most of the existing fossils came from the La Brea Tar Pits in Los Angeles, Smilodon was widely distributed across North America, from coast to coast, reaching as far north as Idaho and Nebraska and extending south into South America. It is most famously associated with California and Florida. The oldest known fossil of Smilodon dates back approximately 500,000 years, while the youngest, discovered during bank construction in Nashville, Tennessee, is just 9,400 years old.

Saber-toothed cat fossil skeleton at La Brea Tar Pits (Erik Olsen)

The La Brea tar pits are a unique and incredibly fruitful outdoor laboratory for understanding animals from 50,000 years of the Pleistocene and the environment in which they lived. Paleontologists have unearthed thousands of Smilodon bones, providing a wealth of information about their anatomy and behavior. The bones show a high rate of injuries, including broken bones and bite marks, which supports the idea that these cats faced significant risks when hunting. In addition to Los Angeles, saber-toothed cat fossils have been found in various parts of California, including San Diego and along the Central Valley, though the La Brea Tar Pits remains the most prolific source.

Imagine that. One of the greatest fossil sites in the world lies amidst the skyscrapers and traffic-clogged streets of Los Angeles. It’s kind of mind-boggling.

Despite their extinction, the legacy of saber-toothed cats endures in the fossil record and in our imagination. Because of it’s ability to capture public interest, ane because the fossil record is so abundant and varied, Smilodon fatalis is now the state fossil of California, symbolizing the state’s rich prehistoric past.

Squid Pro Quo: How the California Market Squid Gives Back to Nature and Economy

California Market Squid. The animal’s skin is covered with thousands of tiny chromatophores that change color and can dramatically transform the squid’s appearance.

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The ocean’s depths are filled with mysterious and fascinating creatures, but few have made quite the splash in both nature and culture as the squid. Sleek, swift, and full of surprises, these little cephalopods are not only culinary favorites but also masters of survival in the ever-changing marine world.

The California market squid, scientifically known as Doryteuthis opalescens, is an integral component of the marine ecosystem and significantly contributes to California’s economy. Although these cephalopods may not captivate public imagination as vividly as their larger, more enigmatic cousins like the giant squid, or even California’s charismatic Two-Spotted Octopus, their role is both ecologically and economically invaluable.

In appearance, Doryteuthis opalescens is a relatively small squid, typically measuring up to a foot in length. It is characterized by its elongated tubular body and mantle. It has a set of eight shorter arms and two longer tentacles, all equipped with suckers for prey capture. The skin of the California market squid contains specialized pigment cells called chromatophores, which allow it to change color in mesmerizing ways. This is not just a display of beauty; the capability is used for camouflage from predators and likely communication with other squids. Their complex eyes are especially remarkable. These structures are highly developed and contain a lens that can focus, similar to the optical system in the human eye, allowing the squid to have keen vision—a trait essential for both hunting and avoiding predators.

The squid’s eyes contain a lens that can focus, similar to the optical system in the human eye, allowing the squid to have keen vision. (Wikipedia)

As for their reproductive habits, the mating and spawning of California market squid generally occur from April to November. The male deposits a spermatophore, or sperm packet, into the female’s mantle cavity. Post-fertilization, the female lays between 200 to 300 eggs, encapsulated in clusters, and attaches them to the substrate on the ocean floor. Neither parent plays a role in the post-fertilization life of these eggs. Both males and females often die shortly after mating, leading to a rather short life span for these creatures, usually between six to nine months.

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The feeding behavior of the California market squid is best described as opportunistic. They primarily consume plankton, small fish, and other marine organisms. This diet situates them in a critical role within the food web, serving as both predator to smaller organisms and prey to larger marine animals. Typically, they inhabit depths less than 300 meters and are more active during nighttime, migrating vertically within the water column to follow prey and avoid predators.

**Squid vessels at night, lights ablaze, looking for market squid in Monterey Bay**. (Photo: *CDFW*)

Economically, the California market squid has an enormous impact. According to reports, it represents the largest fishery in California by volume. In 2022, commercial landings of market squid totaled 147 million pounds and were valued at $88 million, according to the NOAA Fisheries commercial fishing landings database. The fishery for this particular species accounts for nearly 25% of all commercial fishery landings by weight in the state. The significance of the market squid extends to the international sphere, as a considerable portion of the catch is exported to countries in Europe and Asia. In some years, the squid are abundant, but in other years, they are hard to find. Cyclical changes in ocean conditions can change the productivity of California waters and squid populations plummet. In some particularly bad years, the squid fishing industry suffers.

In California, the Fish and Game Commission collaborates with the Department of Fish and Wildlife to actively manage the market squid fishery in line with federal guidelines and the state’s Market Squid Fishery Management Plan.

Changes in climate may end up having a major impact on the squid and the fishery. A 2020 paper from Stanford University published in The American Naturalist, details how climate change has likely ushered the squid north in the Gulf of Alaska, perhaps due to rising ocean temperatures causing the squid to move to more suitable habitats. The study highlights how the squid’s migration could impact local ecosystems, where their presence could alter food chains by competing with or preying on native species like young salmon. This research may predict broader marine species shifts in the future. The squid’s populations are also clearly linked to El Niño cycles.

“As climate change progresses, there are bound to be other species like the California market squid that move to more suitable seas,” Mark Denny, the John B. and Jean De Nault Professor in Marine Science at Hopkins Marine Station and senior author on the paper told Stanford’s Earth Matters Magazine. “Investigating what happens to this squid and the ecosystems around them right now will help researchers predict what could happen to other marine life later.”

As mentioned above, given its economic and ecological relevance, there are stringent regulations and monitoring programs in place to ensure sustainable fishing practices. Seasonal closures of the fishery, especially during peak spawning seasons, and restrictions on the type of fishing gear used are examples of such management strategies. The squid is considered a “smart seafood choice” by NOAA. These measures aim to minimize bycatch and preserve the squid population, thereby sustaining the ecological balance within the marine environment.

However, the agency notes: “Short- and long-term changes in the market squid population are poorly understood, The stock has not been assessed so there are no reliable estimates of the population size and the overfished and overfishing status are unknown.”

Despite being delicious, particularly when fried, the California market squid is far more than just an item on a seafood menu. It is a linchpin species that not only contributes to biodiversity in California, but also holds substantial economic value. Its role in the food web as both predator and prey, as well as its economic impact on both the local and global scales, positions it as a vital species deserving of ongoing scientific study and responsible management.

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Caltech Fly Labs and a Century of Genetic Discovery

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Few organisms in the history of science have been as important to our understanding of life as the humble fruit fly. The genus Drosophila melanogaster holds a particularly esteemed spot among the dozens of model organisms that provide insight into life’s inner workings. For more than 100 years, this tiny, but formidable creature has allowed scientists to unwind the infinitesimal mechanisms that make every living creature on the planet what it is.

And much of the work to understand the fruit fly has taken place and is taking place now, right here in California at the Cal Tech fly labs.

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Over the decades, Drosophila have been key in studying brain, behavior, development, flight mechanics, genetics, and more in many labs across the globe. These tiny, round-bodied, (usually) red-eyed flies might appear irrelevant, but their simplicity makes them ideal models. They’re easy to breed—mix males and females in a test tube, and in 10 days, you have new flies. Their 14,000-gene DNA sequence is relatively short, but extremely well-studied and there are some 8,000 genes which have human analogs. (The fly’s entire genome was fully sequenced in 2000.) Crucially, a century of fruit fly research, much of it led by Caltech, has produced genetic tools for precise genome manipulation and shed light on the act of flight itself.

But how did Drosophila become the darling of genetics?

In the early 20th century, the field of genetics was still in its infancy. Thomas Hunt Morgan, a biologist at Columbia University with a background in embryology and a penchant for skepticism began with an effort to find a simple, cheap, easy-to-breed model organism. At Columbia, he established a laboratory in room 613 of Schermerhorn Hall. This cramped space became famous for groundbreaking research in genetics, with Morgan making innovative use of the common fruit fly.

Thomas Hunt Morgan in the Fly Room at Columbia, 1922 (Cal Tech Archives)

Morgan, who joined Columbia University after teaching at Bryn Mawr College, chose the fruit fly for its ease of breeding and rapid reproduction cycle. Morgan observed a male fly with white eyes instead of the usual red. Curious about this trait’s inheritance, he conducted breeding experiments and discovered that eye color is linked to the X chromosome. He realized a male fly, with one X and one Y chromosome, inherits the white-eye trait from its mother, who provides the X chromosome. This led him to conclude that other traits might also be linked to chromosomes. His extensive experiments in this lab confirmed the chromosomal theory of inheritance, demonstrating that genes are located on chromosomes and that some genes are linked and inherited together.

After his groundbreaking research in genetics at Columbia University, Morgan moved to Pasadena and joined the faculty at CalTech in 1928, where he became the first chairman of its Biology Division and continued his influential work in the field of genetics establishing a strong genetics research program. Morgan’s work, supported by notable students like Alfred Sturtevant and Hermann Muller, laid the foundation for modern genetics and earned him the Nobel Prize in 1933.

CalTech then became a world center for genetics research using the fruit fly. Other notable names involved in fruit fly research at CalTech include Ed Lewis, a student of Morgan, who focused his research on the bithorax complex, a cluster of genes responsible for the development of body segments in Drosophila. His meticulous work over several decades revealed the existence of homeotic and Hox genes, which control the basic body plan of an organism (for which he won the 1995 Nobel Prize).

Novel prize winner Edward Lewis (Nobel Prize.org)

Seymour Benzer, another luminary at CalTech, shifted the focus from genes to behavior. Benzer’s innovative experiments in the 1960s and 1970s sought to understand how genes influence behavior. His work demonstrated that mutations in specific genes could affect circadian rhythms, courtship behaviors, and learning in fruit flies. Benzer’s approach was revolutionary, merging genetics with neurobiology and opening new avenues for exploring the genetic basis of behavior. His contributions are chronicled in Jonathan Weiner’s “Time, Love, Memory: A Great Biologist and His Quest for the Origins of Behavior,” a riveting account of Benzer’s quest to uncover the genetic roots of behavior. Lewis Wolpert in his review for the New York Times wrote, “Benzer has many gifts beyond cleverness. He has that special imagination and view of the world that makes a great scientist.”

Since Benzer’s retirement in 1991, new vanguard in genetics research has taken over at CalTech, which continues to be at the forefront of scientific discovery, driven by a new generation of researchers who are unraveling the complexities of the brain and behavior with unprecedented precision.

Elizabeth Hong is a rising star in biology, with her Hong lab investigating how the brain orders and encodes complex odors. Her research focuses on the olfactory system of Drosophila, which, despite its simplicity, shares many features with the olfactory systems of more complex organisms. Hong’s work involves mapping the synapses and neural circuits that process olfactory information, seeking to understand how different odors are represented in the brain and how these representations influence behavior. Her findings could have profound implications for understanding sensory processing and neural coding in general.

David Anderson, another prominent figure at Caltech, studies the neural mechanisms underlying emotions and behaviors. While much of Anderson’s work now focuses on mice as a model organism, the lab’s research explores how different neural circuits contribute to various emotional states, such as fear, aggression, and pleasure, essentially how emotions are encoded in the circuitry and chemistry of the brain, and how they control animal behavior. Using advanced techniques like optogenetics and calcium imaging, Anderson’s lab can manipulate specific neurons and observe the resulting changes in behavior. This work aims to bridge the gap between neural activity and complex emotional behaviors, providing insights into mental health disorders and potential therapeutic targets.

In 2018, the Anderson laboratory identified a cluster of just three neurons in the fly brain that controls a “threat display” — a specific set of behaviors male fruit flies exhibit when facing a male challenger. During a threat display, a fly will extend its wings, make quick, short lunges forward, and continually reorient itself to face the intruder.

California Institute of Technology (Photo: Erik Olsen)

Michael Dickinson is renowned for his studies on the biomechanics and neural control of flight in Drosophila. In the Dickenson Lab, researchers combine behavioral experiments with computational models and robotic simulations, seeking to understand how flies execute complex flight maneuvers with such precision. His work has broader applications in robotics and may inspire new designs for autonomous flying robots.

“He’s a highly original scientist,” Alexander Borst, a department director at the Max Planck Institute of Neurobiology in Germany, told the New York Times.

Dickinson’s investigations also delve into how sensory information is integrated and processed to guide flight behavior, offering insights into the general principles of motor control and sensory integration.

As science advances, Caltech’s Fly Lab’s remind us of the power of curiosity, perseverance, and the endless quest to uncover the mysteries of life. The tiny fruit fly, with its simple elegance, remains a powerful model organism, driving discoveries that illuminate the complexities of biology and behavior. Just recently, scientists (though not at CalTech) unveiled the first fully image of the fruit fly brain. Smaller than a poppy seed, the brain is an astonishingly complex tangle of 140,000 neurons, joined together by more than 490 feet of wiring.

In essence, the fruit fly remains a key to unlocking the wonders and intricacies of life, and in the Fly Labs at Caltech, that spirit of discovery thrives, ensuring that the legacy of Morgan, Lewis, Benzer, and their successors will continue to inspire generations of scientists to come.

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California Coastline Teems with Whale Skeletons

A whale fall recorded off the Coast of California. (Photo: Ocean Exploration Trust/NOAA)

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In the depths of the ocean, when a whale dies, its carcass sinks to the seafloor, creating a unique and rich ecosystem known as a whale fall. Recently, scientists have discovered an extraordinary number of these whale falls off the coast of Los Angeles—over 60 skeletons, a number that surpasses the total found worldwide since 1977. This remarkable density of whale falls has turned the region into a hotspot for marine biologists and ecologists eager to study these deep-sea oases. A recent video (2019) from the Exploration Vessel (E/V) Nautilus captured the excitement as scientists came upon a whale fall on the Davidson Seamount off California.

(The Davidson Seamount, which we have written about before, is a hotbed of biological activity, a deep sea oasis of life, providing habitat for millions of creatures, including the famous gathering of brooding ocotpus (Muusoctopus robustus) known as the Octopus Garden, seen in video here.)

Whale falls provide a dramatic example of how death can foster life. When a whale carcass settles on the ocean floor, it becomes a feast for a variety of marine creatures. Initially, scavengers like hagfish, sharks, and crabs strip the soft tissues. Over time, the remaining bones support a succession of organisms, including bone-eating worms called Osedax, which bore into the bones and extract lipids. These processes can sustain life for decades, creating a complex and dynamic micro-ecosystem.

The discovery off Los Angeles is attributed to several factors. Detailed surveys of the area have been conducted, coupled with the region’s oxygen-poor waters, which slow decomposition and preserve the skeletons longer. Additionally, the lack of heavy sedimentation ensures that the whale bones remain exposed and easier to find. However, the proximity to busy shipping lanes raises concerns about the potential role of ship strikes in the high number of whale deaths.

Eric Terrill and Sophia Merrifield, oceanographers from the Scripps Institution of Oceanography at UCSD, led surveys in 2021 and 2023 to assess waste spread across 135 square miles of seafloor in the San Pedro Basin. This area, twice the size of Washington, D.C., and located about 15 miles offshore, was used as an industrial dumping ground in the early to mid-1900s. Many of the objects discovered during the survey were barrels containing the banned pesticide DDT and its toxic byproducts.

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Researchers consider it unlikely that the toxic waste and discarded weapons in the area are causing whale deaths. Instead, the high volume of ship traffic is a probable factor, as this area might see more whales killed by ship strikes compared to other regions. The Los Angeles and Long Beach ports, the two busiest in the United States, are located just northeast of the study site, with shipping lanes spreading throughout the area. Additionally, thousands of gray whales migrate through these waters each year, and blue whales regularly feed here, John Calambokidis, a marine biologist with Cascadia Research Collective, a nonprofit in Washington State, told The Atlantic.

Blue whale off the coast of Los Angeles (Photo: Erik Olsen)

Whale falls are crucial not only for the biodiversity they support but also for their role in carbon sequestration. When a whale dies and sinks, it transfers a significant amount of carbon to the deep sea, where it can be stored for centuries. This process helps mitigate the effects of climate change by reducing the amount of carbon dioxide in the atmosphere. The impact is not huge, but scientists say it is significant.

The size of whales plays a significant role in the extent of these ecosystems. Blue whales, the largest animals on Earth, are now seen regularly off the coast. The population of blue whales off the coast of California (as well as Oregon, Washington and Alaska) is known as the Eastern North Pacific blue whale population. This group is one of the largest populations of blue whales globally and migrates between feeding grounds off the coast of California and breeding grounds in the tropical waters of the Pacific Ocean. Their massive bodies provide an abundant food source, supporting a greater diversity and number of species at whale fall sites.

(It should be noted that many articles and Web sites regularly claim that blue whales often reach 100 feet or more. That is false. It is unlikely any blue whale over 80 feet has plied California waters in modern history. John Calambokidis told California Curated that the persistent use of the 100-foot figure can be misleading, especially when the number is used as a reference to all blue whales.)

As many who spend time along the shore know, the waters off California are home to a variety of whale species, including blue whales, humpback whales, gray whales, and fin whales. Blue whale populations, although still endangered, have shown signs of recovery due to conservation efforts. Humpback whales, known for their acrobatic breaches and complex songs, undertake one of the longest migrations of any mammal, traveling between feeding grounds in the Arctic and breeding grounds in Mexico. Fin whales, the second-largest whale species, are also present in these waters, though their populations are also still recovering from historic whaling.

The newfound whale falls off Los Angeles offer a unique opportunity to study these deep-sea ecosystems in greater detail. Researchers are particularly interested in understanding the succession of species that colonize these sites and the overall impact on deep-sea biodiversity. Furthermore, studying whale falls can provide insights into the health of whale populations and the broader marine environment.

The discovery of whale falls in the deep sea reveals the remarkable interdependence of life in our oceans. These massive carcasses, sinking silently to the ocean floor, become rich oases that sustain a diverse array of creatures—from giant scavengers to microscopic bone-eating worms. This cycle of life and death highlights the ocean’s intricate balance, where even in the darkest depths, every organism contributes to a larger, interconnected web. Gaining a deeper understanding of these hidden processes is vital, not just for the sake of marine conservation, but for preserving the overall health and resilience of our planet’s ecosystems.

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