California is home to an impressive number of bird species, with over 700 recorded throughout the state. From the rocky shores of the Pacific coast to the towering peaks of the Sierra Nevada, California’s diverse landscapes provide habitats for a wide range of birdlife. Many of these species are endemic to California, meaning they are found nowhere else in the world. The state’s unique geography and climate, as well as its location on the Pacific Flyway migration route, make it a haven for birdwatchers and ornithologists alike.
One of the most common birds in California, probably familiar to anyone whether a backyard enthusiast or committed ornithologist is the house finch. The house finch (Haemorhous mexicanus) is a small passerine (perching) bird that is native to western North America, including California. This bird is widely known for its vibrant red plumage and melodic song, making it a beloved sight and sound in backyards across the state.
House finches are a member of the finch family, Fringillidae, which includes all true finches. They are thought to have originated from the deserts of Mexico and the southwestern United States. Their range has since expanded to cover much of North America.
Finches are famously associated with Charles Darwin and his theory of evolution by natural selection. During his voyage on the HMS Beagle, Darwin observed finches on the Galápagos Islands, noting the significant variations in their beak shapes and sizes. These differences were adaptations to the specific diets available on their respective islands. Darwin’s study of these finches helped him develop the concept that species evolve over time through natural selection, where advantageous traits become more common in a population. This observation provided crucial evidence for his groundbreaking work, “On the Origin of Species.”
House finches are small birds, measuring about 5-6 inches in length and weighing between 0.6-1.0 ounces. They have a stout, conical beak that is adapted for cracking open seeds, their primary source of food. The male house finch is easily recognizable by its bright red head and breast, while the female has a duller brownish-gray coloration. However, in some areas, there are color variations in the males, such as yellow, orange, or even a rose-pink color.
House finches primarily feed on seeds, including those from sunflowers, dandelions, thistles, and various grasses. They are also known to eat some fruits and insects, particularly during the breeding season when protein is essential for the growth of their young. House finches have a unique feeding habit in that they use their tongue to extract seeds from the seed capsules, which they then crush with their beaks.
House finches are monogamous and form pair bonds during the breeding season, which typically starts in late winter and lasts through early summer. The male house finch will sing and perform courtship displays to attract a mate, often presenting the female with a gift of food. Once the pair has formed, they will work together to build a small nest using grass, twigs, and other plant materials.
House finches are a common sight in backyards, parks, and other areas with ample vegetation. They are often seen perched on wires, branches, or feeders, where they will socialize with other birds, including other finches, sparrows, and juncos. House finches are also known for their acrobatic abilities, often clinging to branches and twigs while feeding.
In addition to their acrobatics, house finches are known for their melodic song. Males will sing throughout the day, particularly during the breeding season, to attract mates and establish territories. The song of the house finch is a warbling melody that can be heard from a considerable distance.
House finch (Erik Olsen)
Research has shown that male house finches learn their songs from adult males, typically their fathers, during a critical period in their early life. This learning process is akin to how humans acquire language, involving both genetic predisposition and environmental influences. A study published in the journal “Animal Behaviour” found that house finch songs are composed of a variety of syllables that can be combined in numerous ways, leading to a wide range of unique songs within populations.
Interestingly, these songs play a crucial role in mate attraction and territorial defense. Females tend to prefer males with more complex and diverse songs, which are indicative of the male’s overall health and genetic fitness. Moreover, regional dialects have been observed, with finches in different geographic locations exhibiting distinct song patterns. This geographic variation is believed to result from both cultural transmission and genetic drift, making the house finch’s song an excellent model for studying the evolution of communication and social behavior in birds.
House finch painting
In California, house finches are a common sight and have adapted well to urban and suburban environments. They are often attracted to bird feeders, particularly those filled with sunflower seeds, which they can easily crack open with their beaks.
The house finch’s vibrant plumage, melodic song, and acrobatic abilities make it a joy to observe in the wild or in our own backyards. As with many bird species, it is essential that we continue to protect their habitats and ensure that they have access to adequate food sources to thrive.
California is known for its sunny beaches, bustling cities, and iconic landmarks such as the Golden Gate Bridge and Hollywood sign. However, the state is also home to a wealth of scientific discoveries and phenomena that are not as well-known. From ancient fossils to cutting-edge research, California has a lot to offer in the realm of science. In this list, we’ll explore ten of the most fascinating scientific things that you probably didn’t know about California. Get ready to be amazed by the natural wonders and innovative research that make this state such a unique and exciting place for science enthusiasts.
California is home to the tallest tree in the world, a coastal redwood named Hyperion that measures 379.7 feet (115.7 meters) in height. The state is also home to the largest (by volume) tree, named General Sherman in Sequoia National Park. General Sherman is 274.9 feet high and has a diameter at its base of 36 feet, giving it a circumference of 113 feet. General Sherman’s estimated volume is around 52,508 cubic feet (1,487 cubic meters), which would correspond to an estimated weight of around 2.7 million pounds.
The Salton Sea, a large inland lake in southern California, is actually an accidental body of water that was created by a flood in 1905 when Colorado River floodwater breached an irrigation canal being constructed in the Imperial Valley and flowed into the Salton Sink.
TheSan Andreas Fault, the state’s best-known and most dangerous fault that runs through the middle of California and to the coast, moves about 2 inches (5 centimeters) per year (or, so they say, the speed that a fingernail grows).
The state of California has more national parks than any other state in the US, with nine in total. Among them is one of the crown jewels of the National Park system: Yosemite National Park.
California is one of the only places in the world where you can find naturally occurring asphalt, at the La Brea Tar Pits in Los Angeles.
The oldest living organism on Earth, a bristlecone pine tree named Methuselah, can be found in the White Mountains of California and is over 4,800 years old.
TheMonterey Bay Aquarium in Monterey, California was the first aquarium to successfully keep a great white shark in captivity for more than 16 days. The first great white that the aquarium tried to display died after 11 days in 1984 because it would not eat.
The Joshua Tree, a type of yucca plant (NOT a tree) found in the Mojave Desert, is named after the biblical figure Joshua because of its outstretched branches that resemble a person reaching up to the sky in prayer.
The California grizzly bear, which appears on the state flag, went extinct in the early 1900s due to hunting and habitat loss. The last California grizzly was seen near Yosemite in 1924, going extinct after decades of hunting. Fossils of the California grizzly can be seen at the La Brea tar Pits.
The California Institute of Technology, also known as Caltech, is one of the world’s leading scientific research institutions and has produced 39 Nobel laureates, more than any other university in the world.
A Pacific White-Sided Dolphin swims alongside a boat off Newport Beach, California
For those who are fortunate enough to live near the coast of California, Dolphin sightings are a frequent delight. Dolphins are a diverse group of marine mammals found in all of the world’s oceans, but they are especially abundant in California. The California coast is home to numerous species of dolphins, each with their own unique characteristics and behaviors. An afternoon spent at the beach will very often result in a sighting of these magnificent and majestic animals frolicking in the waves.
For those who may not know, dolphins and porpoises are toothed whales. Both porpoises and dolphins are members of the same scientific order, Cetacea, which includes all whales, including the magnificent blues, grey whales and humpbacks that also ply the California coast.
The exact number of dolphins off the California coast is impossible to know since many species migrate and no authoritative study of their total numbers has ever been published. But one estimate of the dolphin population in Southern California suggests that well over half a million live between the frigid, rocky coastal waters of Monterey and San Diego. Scientists have documented 11 species of dolphins in California’s waters alone. We take a look at a few of those here.
One of the most common, and beautiful, dolphins found off the coast of California is the Pacific White-Sided Dolphin (Lagenorhyncus obliquidens). These dolphins are easily recognized by their distinctive markings, which include a white underbelly and gray and white stripes along the sides. White-Sided Dolphins can reach up to 400 pounds and can grow to 8 feet in length, with males typically being larger than females. They are also known for their energetic and playful behavior, often bow-riding the waves alongside boats and performing wonderful acrobatics in the air. Boaters and whale watchers can witness pods of these animals following their boat for half an hour or more, often swimming on their sides near the surface and gazing up with attentive eyes.
White-sided dolphins feed on a variety of prey, but mostly consume fish and squid. They are skilled hunters and have been known to work together in groups to corral and capture their meals.
Another species found off the California coast is the Common Dolphin (Delphinus delphis). These dolphins have a distinctive sleek, hydrodynamic shape, with a dark gray or black dorsal region and a light gray or white underbelly. Common Dolphins are also known for their high level of activity, often seen jumping and playing in the water. Common dolphins can travel 100 miles in a single day.
This species is one of the most well-known and widely distributed marine mammals, and is often associated with playful acrobatics and a high level of intelligence. California is home to several large “super pods” or “megapods” of Common Dolphins that are often seen by boaters or whale-watching tours. As the American Cetacean Society explains, common dolphins typically travel and hunt in large herds of hundreds or even thousands. One resident megapod frequently forages between Ventura and Dana Point.
A Pacific White-Sided Dolphin
Common dolphins have been the subject of numerous studies examining their cognitive abilities. They are known to have complex social relationships and to exhibit behaviors that suggest a high level of problem-solving ability and adaptability. In addition, they are capable of using tools, such as seaweed, to herd fish and protect themselves from predators. They also have excellent memories and are able to recognize individual dolphins and remember past experiences.
The Bottlenose Dolphin (Tursiops truncatus) is another species that can be found off the coast of California. This species is easily recognizable due to its large size and beak-like snout. Bottlenose Dolphins are known for their intelligence and playful nature, and are often (unfortunately) used in marine mammal shows and research programs.
Bottlenose dolphins have a complex mating system that involves a variety of behaviors, including courtship displays, vocalizations, and physical contact. Female Bottlenose dolphins give birth to a single calf every three to five years, and the calves are nursed by their mothers for up to a year. Male Bottlenose dolphins compete for access to females, and the strongest and most dominant males are the most successful at mating.
A lesser-known (and seen) species found in the waters of California is the Risso’s Dolphin (Grampus griseus). These dolphins are identified by their tall, curved, sickle-shaped dorsal fin located mid-way down their back. Often they also have distinctive scars and scratches, which are believed to be caused by “teeth raking” between other dolphins. They also frequently have circular markings, likely from encounters with squid or lampreys. Risso’s Dolphins are generally less active than the other species found in the area, and are often seen alone or in small groups.
Finally, the Dall’s Porpoise (Phocoenoides dalli) is another species that can be found in the waters off the California coast. These dolphins are identified by their short, stocky bodies and small triangular dorsal fins. Dall’s Porpoises are known for their speed and agility, and are often seen riding the bow waves of boats.
Few places on earth match the coast of California for the sheer number and variety of dolphins that swim in the cool, nutrient-rich waters that well up from the state’s deep canyons. So next time you’re near the coast, keep an eye out for these incredible creatures and enjoy the show!
The drive from Los Angeles north along Highway 395 towards Mammoth Lakes is one of the great road trips in all of California. The drive offers breathtaking views of the Sierra Nevada mountain range, the (much older) White Mountains, the vibrantly picturesque Owens Valley, and the Mojave Desert (which, let’s face it, is kinda boring, especially if you’ve done the drive as many times as I have). The highway winds its way through a diverse range of geological and historical features, making it an ideal destination for road trippers, history buffs, and outdoor enthusiasts alike.
One of the highway’s more magnificent sights is observable when making a left turn up Whitney Portal Road in Lone Pine. Just a few miles up, you will find the magnificent Alabama Hills, a range of hills located in the Owens Valley near the main entrance to Mount Whitney. The hills are known for their unique geological formations, including massive rounded boulders and natural arches, and their rich history and cultural significance.
Scene from Iron Man with Robert Downey Jr. The Alabama Hills stood in for Afghanistan.
The hills are world famous not just for their scenic beauty and appeal to photographers. They have also appeared in more than 700 movie and television productions, including some of the most famous and iconic Westerns ever made. The first film made there was the silent 1920 western “The Round Up,” starring Roscoe “Fatty” Arbuckle.
More recently, several major films made use of the Alabama Hills as exotic backdrops. In addition to Iron Man (2008), where Tony Stark crash-lands after escaping captivity, and Gladiator (2000), where the rugged landscape serves as part of the journey for Maximus, the Alabama Hills has also appeared in:
The Lone Ranger (2013) – The dramatic landscape contributes to the film’s adventurous, untamed feel.
Django Unchained (2012) – Here, the rocky outcrops stand in for the American West, giving a distinctive backdrop to Quentin Tarantino’s Western.
Tremors (1990) – The Hills’ remote, desolate look is a perfect setting for this cult classic monster movie.
Star Trek V: The Final Frontier (1989) – Alabama Hills doubles as alien terrain in this installment of the sci-fi series.
Geologically, the Alabama Hills are primarily made up of biotite monzogranite, an intrusive igneous rock, rather than metamorphic rock. This type of granite was formed from magma that cooled slowly beneath the Earth’s surface, allowing large crystals of quartz, feldspar, and biotite to develop. The landscape, featuring spherical, egg-shaped, teardrop forms, and natural arches, was sculpted over millions of years through a combination of chemical weathering and wind erosion.
California barrel cactus or desert barrel cactus Ferocactus cylindraceus at the Alabama Hills (Erik Olsen)
One of the most striking aspects of the Alabama Hills is the sharp contrast they present with the neighboring glacially carved ridges of the Sierra Nevada. There are almost 10,000 feet of vertical difference between Mount Whitney’s majestic granite peaks and the rolling boulders of the Alabama Hills. The Sierra’s jagged, ice-carved peaks seem to rise abruptly from the gentle, rounded contours of the hills. Geologically, both landforms consist of the same granitic rock, but they have been shaped by very different forces. While glaciers carved the high peaks of the Sierra Nevada, creating sharp ridges and deep valleys, the Alabama Hills experienced a slower, more gradual transformation. Erosion by wind, rain, and temperature changes slowly sculpted the monzogranite, creating the unique and surreal formations we see today.
While the geological history of the Alabama Hills is well known, its biology is equally fascinating. At first glance, the landscape may seem inhospitable to life, but a closer inspection reveals a surprisingly diverse ecosystem adapted to the harsh conditions. In recent years, new studies have shed light on the resilience and adaptation strategies of plants and animals in this region.
The Alabama Hills are home to a variety of plant species, many of which have evolved to survive in the dry, rocky soil. Sagebrush, saltbush, and other desert plants dominate the landscape, while prickly cacti add a distinct desert charm. One particularly intriguing plant is Atriplex hymenelytra, commonly known as desert holly, which has adapted to the high-salinity soil by developing silvery leaves that reflect sunlight, reducing water loss and protecting the plant from extreme temperatures.
Atriplex hymenelytra, Desert holly.
Wildlife, too, has found ways to thrive in this rugged terrain. The Alabama Hills are home to numerous bird species, reptiles, and small mammals. Species like the western fence lizard, desert cottontail, and even mountain lions are part of this surprisingly vibrant ecosystem. Birdwatchers can often spot red-tailed hawks, ravens, and sometimes even golden eagles soaring above the hills, taking advantage of the thermal updrafts created by the warm rock surfaces.
Recent studies have added to our understanding of the Alabama Hills’ unique environment. One particularly interesting research project conducted by ecologists focuses on the role of cryptobiotic soil crusts—thin layers of lichens, mosses, and bacteria that live on the surface of desert soils. These crusts play a critical role in preventing erosion and retaining moisture in arid environments like the Alabama Hills. The study revealed that these soil crusts are more widespread than previously thought, and their destruction by human activity, such as off-road vehicle use, could have significant ecological consequences.
Alabama Hills vegetation (Erik Olsen)
Cryptobiotic crusts act as a protective cover on desert soils, anchoring loose particles and reducing susceptibility to wind and water erosion. When these crusts are damaged, the soil is left vulnerable to erosion, which can lead to large-scale soil loss. This erosion depletes the land of nutrients, reduces soil fertility, and diminishes its ability to support native vegetation.
Additionally, geologists continue to study the impact of erosion and weathering on the Alabama Hills’ distinctive rock formations. Advances in remote sensing technology have allowed scientists to map the region’s geological features in more detail than ever before, providing new insights into how these formations developed and how they are likely to change in the future.
The hills were (controversially) named after the CSS Alabama, a Confederate warship that operated during the American Civil War. The name was given to the hills by a group of Confederate sympathizers who were prospecting in the area in the 1860s. Several groups have launched campaigns to change the name to erase its connection with Southern slavery.
Alabama Hills (Erik Olsen)
In addition to their geological and historical importance, the Alabama Hills are also important for their recreational opportunities. The hills offer a variety of outdoor activities such as hiking, rock climbing, and photography. The range of hills is also a popular spot for stargazers and astro-photographers, due to the relatively low light pollution in the region.
The Alabama Hills are a must-see destination for anyone interested in geology, history, or outdoor activities in California.
Driving up Highway 395 toward Mammoth Lakes is one of the most breathtaking road trips in California. The highway winds through the rugged Eastern Sierra, offering jaw-dropping views of snow-crusted peaks, alpine meadows, and mottled green chaparral plains. But beneath the dramatic landscape lies a hidden danger, an ancient volcanic giant boils beneath the surface.
The Long Valley Caldera in eastern California is an extraordinary geological feature, spanning about 20 miles in length and 11 miles in width. It owes its existence to one of the most dramatic volcanic events in Earth’s history, a super eruption that occurred approximately 760,000 years ago. This event, known as the Bishop Tuff eruption, ejected an estimated 150 cubic miles of molten rock and ash into the atmosphere, far surpassing the 1980 eruption of Mount St. Helens, which released just 0.3 cubic miles of material. The magnitude of the Bishop Tuff eruption resulted in the collapse of the ground above the magma chamber, creating a massive depression known as a caldera. The ash spread for hundreds of miles.
It’s hard to get your head around how big this eruption was.
The Long Valley Caldera is one of the most active volcanic sites in the United States. Here, the Owens River flows through it, winding south through Owens Valley.(Erik Olsen)
The Long Valley Caldera is evidence that California is a volcanic state. It sits near one of the nation’s most popular ski towns, Mammoth Lakes. Mammoth Mountain itself is volcanic too, a younger pile of lava domes that rose along the edge of the caldera tens of thousands of years after the giant eruption that created the basin. Geothermal activity, visible in the form of hot springs, fumaroles, and hydrothermal systems, is a ubiquitous feature of the landscape. This activity has made the caldera a hub for geothermal energy production, with the Casa Diablo thermal power plant utilizing its subterranean heat to generate electricity. The energy produced at Casa Diablo is enough to power about 36,000 homes, making it an important renewable energy source for the region.
Casa Diablo Geothermal Facility, Long Valley Caldera, California (Erik Olsen)
The surface of the caldera is also marked by the Bishop Tuff, a layer of welded volcanic ash that provides a lasting record of the eruption’s intensity and the pyroclastic flows that reshaped the landscape. Pyroclastic flows are fast-moving, hot clouds of gas and volcanic material that can destroy everything in their path. Here’s a video from Indonesia showing how quickly they move. Often they are considered more dangerous than the lava that pours out of an erupting volcano. For example, pyroclastic flows killed far more people at Pompeii than lava, as the 79 AD eruption of Mount Vesuvius unleashed fast-moving clouds of superheated gas, ash, and volcanic debris that raced down the slopes at over 100 mph, reaching temperatures above 1,000°F, instantly asphyxiating and incinerating thousands, while the slower-moving lava played a minimal role in fatalities.
Geothermal features at the Long Valley Caldera also support microbial communities of thermophilic bacteria and algae, which thrive in the caldera’s hot springs and fumaroles. They carpet the ground for miles, making the surface crunchy and moonscape-like. These organisms not only influence the terrain by contributing to mineral precipitation but also serve as models for studying life in extreme environments, offering analogs for early Earth and potential extraterrestrial ecosystems. Scientists are just beginning to understand how extremophile bacteria live and thrive in deep ocean vent systems.
The Owens River flows through the Long Valley Caldera near Mammoth Lakes, California (Erik Olsen)
While the caldera’s formation was sudden and catastrophic — ash spread across much of western North America, as far wast as Nebraska — its story stretches back millions of years. Scientific studies at the Long Valley Caldera have advanced our understanding of volcanic processes, crustal dynamics, and geothermal systems. The Long Valley Caldera sits within the Basin and Range Province, an area of North America characterized by extensional tectonics, where the Earth’s crust is being pulled apart, allowing magma to rise to the surface.
Using seismic tomography, researchers have mapped the magma chamber beneath the caldera, revealing a layered structure with a partially molten zone capped by solidified magma, like a hot dish of au gratin potatoes. A 2023 study published in Science Advances, explains the periodic episodes of unrest at the caldera and offers scientists a baseline to understand potential future activity. Even after the formation of the caldera, volcanic activity continued in the area. The nearby Mono-Inyo Craters area has seen eruptions as recently as 600 years ago, a blink of an eye geologically speaking.
Horseshoe Lake in the Mammoth Lakes area, where underground carbon dioxide emissions have caused widespread tree die-off (Photo: Erik Olsen)
Another place where the region’s volcanic activity can be experienced firsthand is Horseshoe Lake, where carbon dioxide continuously seeps from the ground, suffocating tree roots and causing a vast die-off of trees. The result is a barren, almost ghostly landscape of skeletal trunks and barren ground. It’s a fascinating place to explore, though the posted warnings are hard to ignore. Signs around the area caution visitors about the danger of carbon dioxide — odorless and colorless — that can accumulate invisibly to levels that are dangerous, even deadly, if inhaled.
The caldera remains active. Ground deformation studies, using GPS and InSAR technology (satellites), have tracked uplift in the caldera’s floor, offering critical data on magma movement and hydrothermal activity. In a 2016 study published in Geophysical Research Letters, researchers linked changes in uplift patterns to deeper magmatic processes, and scientists are constantly monitoring the area should activity increase. In 1980, a series of magnitude 6 earthquakes occurred the southern margin, drawing the attention of United States Geological Survey (USGS) volcanologists. The earthquakes were accompanied by noticeable uplift in the caldera’s floor, a sign of magma movement beneath the surface. One spot of particular interest is a resurgent dome, just outside Mammoth, where the floor of the caldera has slowly lifted upward as magma pushes from below. Over the past several decades the ground there has risen and fallen by several feet as the volcanic system beneath Long Valley expands and contracts, although scientists generally say that the level of volcanic unrest at Long Valley has declined since the early 1980s.
Mono Lake is home to thermophilic (heat-loving) and extremophilic (extreme-condition-loving) bacteria. These microorganisms thrive in the lake’s unusual environment, characterized by high alkalinity, high salinity, and elevated levels of carbonate. (Erik Olsen)
As a result of the 1980s studies, the town of Mammoth Lakes took proactive measures to ensure public safety. Local authorities constructed new road, an “emergency evacuation route,” to serve as an escape in the event of a volcanic eruption or other natural disaster stemming from the Long Valley Caldera. After local businesses and residents complained that the name was scaring people away, in an act of geological marketing, it was changed to the Mammoth Scenic Loop to emphasize the area’s beauty and appeal. That said, the USGS intensified its monitoring efforts, implementing a color-coded alert system to communicate volcanic activity risks.
Beyond its scientific significance, and the small, but not insignificant potential for catastrophe, the Long Valley Caldera is a wonderful destination for outdoors folk. Numerous hot springs dot the landscape and are immensely popular among tourists and residents. There are amazing opportunities to hike and fish during the summer and superb skiing in the winter months. So, despite the dangers, which I don’t want to overstate here, it’s an awesome place.
Sierra reflected in Little Alkali Lake near the Long Valley Caldera (Erik Olsen)
Of course, Mammoth Mountain does has its geologic dangers—like I said, it’s a volcano. On April 6, 2006, three members of the Mammoth Mountain ski patrol tragically lost their lives after falling into a volcanic fumarole near the summit. The incident happened while they were conducting safety operations to secure a snow-covered geothermal vent following an unprecedented snowfall. If you’ve ever skied Mammoth before, there is a distinct sulphurous smell around the Christmas Bowl ski run at Chair 3 near McCoy Station.
Steam from an active fumarole near McCoy Station on Mammoth Mountain in 2012. (Flickr)
Standing in the middle of the Long Valley Caldera, it’s hard to grasp the scale of what happened here. It’s an extraordinary place to spend time, especially at night, when the Sierra sky is speckled with stars and the valley becomes silent, except for the whisper of the occasional wind gust. The ground beneath your feet is the result of an astonishing geologic event a long time ago, but it’s still active. There are few places quite like it in California. And for a state filled with volcanoes, that’s saying something.
It started by asking one of the biggest questions of them all: how old is the earth?
One might think that we’ve known the answer to this question for a long time, but the truth is that a definitive age for our planet was not established until 1953, and it happened right here in California.
Some of the earliest estimates of the earth’s age were derived from the Bible. Religious scholars centuries ago did some simple math, synthesizing a number of passages of Biblical scripture and calculated that the time to their present-day from the story of Genesis was around 6,000 years. That must have seemed like a really long time to people back then.
Of course, once science got involved, the estimated age changed dramatically, but even into the 18th century, people’s sense of geologic time was still on human scales, largely incapable of comprehending an age into the billions of years. In 1779, the Comte du Buffon tried to obtain a value for the age of Earth using an experiment: He created a small globe that resembled Earth in composition and then measured its rate of cooling. His conclusion: Earth was about 75,000 years old.
But in 1907, scientists developed the technique of radiometric dating, allowing scientists to compare the amount of uranium in rock with the amount of lead, the radioactive decay byproduct of uranium. If there was more lead in a rock, then there was less uranium, and thus the rock was determined to be older. Using this technique in 1913, British geologist Arthur Holmes put the Earth’s age at about 1.6 billion years, and in 1947, he pushed the age to about 3.4 billion years. Not bad. That was the (mostly) accepted figure when geochemist Clair Patterson arrived at the California Institute of Technology in Pasadena from the University of Chicago in 1952. (Radiometric dating remains today the predominant way geologists measure the age of rocks.)
By employing a much more precise methodology, and using samples from the Canyon Diablo meteorite, Patterson was able to place the creation of the solar system, and its planetary bodies such as the earth, at around 4.6 billion years. (It is assumed that the meteorite formed at the same time as the rest of the solar system, including Earth). Subsequent studies have confirmed this number and it remains the accepted age of our planet.
Patterson’s discovery and the techniques he developed to extract and measure lead isotopes led one Caltech colleague to call his efforts “one of the most remarkable achievements in the whole field of geochemistry.”
But Patterson was not done.
In the course of his work on lead isotopes, Patterson began to realize that lead was far more prevalent in the environment that people imagined. In the experiments he was doing at Caltech, lead was everywhere.
Clair Patterson at CalTech (Courtesy of the Archives, California Institute of Technology)
“There was lead there that didn’t belong there,” Patterson recalled in a CalTech oral history. “More than there was supposed to be. Where did it come from?”
Patterson’s discovery was “one of the most remarkable achievements in the whole field of geochemistry.”
Barclay Kamb, California Institute of Technology
Patterson was flummoxed by the large amounts of environmental lead he was seeing in his experiments. It seemed to be everywhere: in the water, air and in people’s hair, skin and blood. Figuring out why this was the case took him the rest of his career.
He found it so hard to get reliable measurements for his earth’s age experiments that he built one of the first scientific “clean rooms”, now an indispensable part of many scientific disciplines, and a precursor to the ultra-clean semiconductor fabrication plants (so-called “fabs”) where microprocessor chips are made. In fact, at that time, Patterson’s lab was the cleanest laboratory in the world.
On the occasion of Clair Patterson receiving the Tyler Prize. The Tyler Prize is awarded for environmental achievement. (Courtesy of the Archives, California Institute of Technology)
To better understand this puzzle, Patterson turned to the oceans, and what he found astonished him. He knew that if he compared the lead levels in shallow and deep water, he could determine how oceanic lead had changed over time. In his experiments, he discovered that in the ocean’s oldest columns of water, down deep, there was little lead, but towards the surface, where younger water circulates, lead values spiked by 20 times.
Then, going back millions of years, he analyzed microscopic plant and animal life from deep sediments and discovered that they contained 1/10 to 1/100th the amount of lead found at the time around the globe.
Smog in Los Angeles in 1970. (Courtesy of UCLA Library Special Collections – Los Angeles Times Photographic Archive)
He decided to look in places far from industrial centers, ice caves in Greenland and Antarctica, where he would be able to see clearly how much lead was in the environment many years ago. He was able to show a dramatic increase in environmental lead beginning with the start of lead smelting in Greek and Roman times. Historians long ago documented the vast amounts of lead that were mined in Rome. Lead pipes connected Roman homes, filled up bathtubs and fountains and carried water from town to town. Many Romans knew of lead’s dangers, but little was done. Rome, we all know, collapsed. Jean David C. Boulakia, writing in the American Journal of Archaeology, said: “The uses of lead were so extensive that lead poisoning, plumbism, has sometimes been given as one of the causes of the degeneracy of Roman citizens. Perhaps, after contributing to the rise of the Empire, lead helped to precipitate its fall.”
In his Greenland work, Patterson’s data showed a “200- or 300-fold increase” in lead from the 1700s to the present day; and, most astonishing, the largest concentrations occurred only in the last three decades. Were we, like the Romans, perhaps on the brink of an environmental calamity that could hasten the end of our civilization? Not if Patterson could help it.
California Institute of Technology. Credit: Erik Olsen
That may be far too grandiose and speculative, but there was no doubting that there was so much more lead in the modern world, and it seemed to have appeared only recently. But why? And how?
In a Eureka moment, Patterson realized that the time frame of atmospheric lead’s rise he was seeing in his samples seemed to correlate perfectly with the advent of the automobile, and, more specifically, with the advent of leaded gasoline.
Leaded gas became a thing in the 1920s. Previously, car engines were plagued by a loud knocking sound made when pockets of air and fuel prematurely exploded inside an internal combustion engine. The effect also dramatically reduced the engine’s efficiency. Automobile companies, seeking to get rid of the noise, discovered that by adding tetraethyl lead to gasoline, they could stop the knocking sound, and so-called Ethyl gasoline was born. “Fill her up with Ethyl,” people used to say when pulling up to the pump.
Despite what the Romans may have known about lead, it was still an immensely popular material. It was widely used in plumbing well into the 20th century as well as in paints and various industrial products. But there was little action taken to remove lead from our daily lives. The lead in a pipe or wall paint is one thing (hey, don’t eat it!), but pervasive lead in our air and water is something different.
After World War I, every household wanted a car and the auto sales began to explode. Cars were perhaps the most practical invention of the early 20th century. They changed everything: roads, cities, work-life and travel. And no one wanted their cars to make that infernal racket. So the lead additive industry boomed, too. By the 1960s, leaded gasoline accounted for 90% of all fuel sold worldwide.
But there signs even then that something was wrong with lead.
A New York Times story going back to 1924 documented how one man was killed and another driven insane by inhaling gases released in the production of the tetraethyl lead at the Bayway plant of the Standard Oil Company at Elizabeth, N.J. Many more cases of lead poisoning were documented in ensuing years, with studies showing that it not only leads to physical illness but also to serious mental problems and lower IQs. No one, however, was drawing the connection between all the lead being pumped into the air by automobiles and the potential health impacts. Patterson saw the connection.
Ford Model T. Credit: Harry Shipler
When Patterson published his findings in 1963, he was met with both applause and derision. The billion-dollar oil and gas industry fought his ideas vigorously, trying to impugn his methods and his character. They even tried to pay him off to study something else. But it soon became apparent that Patterson was right. Patterson and other health officials realized that If nothing was done, the result could be a global health crisis that could end up causing millions of human deaths. Perhaps the decline of civilization itself.
Patterson was called before Congress to testify on his findings, and while his arguments made little traction, they caught the attention of the nascent environmental movement in America, which had largely come into being as a result of Rachel Carson’s explosive 1962 book Silent Spring, which documented the decline in bird and other wildlife as a result of the spraying of DDT for mosquito control. People were now alert to poisons in the environment, and they’d come to realize that some of the industrial giants that were the foundation of our economy were also having serious impacts on the planet’s health.
Downtown Los Angeles today. (Erik Olsen)
Patterson was unrelenting in making his case, but he still faced serious opposition from the Ethyl companies and from Detroit. The government took half-hearted measures to address the problem. The EPA suggested reducing lead in gasoline step by step, to 60 to 65 percent by 1977. This enraged industry, but also Patterson, who felt that wasn’t nearly enough. Industry sued and the case to the courts. Meanwhile, Patterson continued his research, collecting samples around Yosemite, which showed definitely that the large rise in atmospheric lead was new and it was coming from the cities (in this case, nearby San Francisco and Los Angeles). He analyzed human remains from Egyptian mummies and Peruvian graves and found they contained far less lead than modern bones, nearly 600 times less.
Years would pass with more hearings, more experiments, and the question of whether the EPA should regulate leaded gas more heavily went to U.S. Court of Appeals. The EPA won, 5-4. “Man’s ability to alter his environment,” the court ruled, “has developed far more rapidly than his ability to foresee with certainty the effects of his alterations.”
The Clean Air Act of 1970 initiated the development of national air-quality standards, including emission controls on cars.
Drone over Los Angeles. (Credit: Erik Olsen)
In 1976, the EPA’s new rules went into effect and the results were almost immediate: environmental lead plummeted. The numbers continued to plummet as lead was further banned as a gasoline additive and from other products like canned seafood (lead was used as a sealant). Amazingly, there was still tremendous denial within American industry.
Although the use of leaded gas declined dramatically beginning with the Clear Air Act, it wasn’t until 1986, when the EPA called for a near ban of leaded gasoline that we seemed to finally be close to ridding ourselves of the scourge of atmospheric lead. With the amendment of the Clean Air Act four years later, it became unlawful for leaded gasoline to be sold at all at service stations beginning December 31, 1995. Patterson died just three weeks earlier at the age of 73.
Clair Patterson is a name that few people know today, yet his work not only changed our understanding of the earth itself, but also likely saved millions of lives. When Patterson was finally accepted into the National Academy of Science in 1987, Barclay Kamb, a Caltech colleague, summed his career up thusly: “His thinking and imagination are so far ahead of the times that he has often gone misunderstood and unappreciated for years, until his colleagues finally caught up and realized he was right.”
Clair Patterson is one of the most unsung of the great 20th-century scientists, and his name deserves to be better known.
Imagine a world lost in deep time. The atmosphere held less oxygen than at any point since the Cambrian explosion, and the land was dominated by iconic dinosaurs like Allosaurus, Brachiosaurus, Archaeopteryx, and Stegosaurus. It was an era poised for a new type of plant life that would come to define the landscape—cycads. While Jurassic forests are often depicted as dense with ferns, with their coiled fronds and lush foliage, these plants were not the sole stars of the ancient botanical world.
The true giants of the Jurassic flora were the cycads, seed-bearing plants with stout, woody trunks and crowns of stiff, feather-like evergreen leaves. In fact, the Jurassic is often referred to as the “Age of Cycads”. Cycads thrived during this period, approximately 280 to 145 million years ago, as evidenced by abundant fossils. These resilient plants, which once dominated prehistoric landscapes, have remarkably endured the passage of time, remaining largely unchanged (although this is now disputed) and offering a living glimpse into a world ruled by dinosaurs.
One of the most remarkable features of cycads is the toughness of their leaves. Touch them with your fingers. They have a much greater stiffness than most other plants. Cycad leaves are thick, leathery, and often waxy to the touch, with a heavy cuticle, a protective outer layer that makes them remarkably durable. Unlike the soft, broad leaves of many modern plants, cycad fronds are built to withstand intense sunlight, conserve water in dry environments, and deter herbivores. The stiff, sometimes spiny edges of the leaves would have made them a difficult meal, offering a critical evolutionary advantage during a time when giant plant-eating dinosaurs roamed the Earth.
Cycad leaves are quite hard and resistant to insects. Evidence shows that dinosaurs ate cycad leaves regularly. (Photo: Erik Olsen)
Despite their formidable defenses, evidence shows that dinosaurs did in fact eat cycads. Fossilized dinosaur dung, known as coprolites, has been found containing fragments of cycad tissues and pollen. Some herbivorous dinosaurs like Stegosaurus and Ankylosaurus are believed to have browsed on cycads, along with other tough plants of the Mesozoic landscape. These animals likely evolved strong jaws and specialized teeth capable of grinding down fibrous, sturdy plant material. In turn, the resilience of cycad leaves helped the plants survive repeated grazing and harsh environmental stresses, allowing them to persist across millions of years into the present day. FYI: Flowering plants, or angiosperms, only came into being during the late reign of the dinosaurs, during the Cretaceous Period (145–66 million years ago).
Recent fossil discoveries are also reshaping how scientists view cycads. In 2023, researchers uncovered an 80-million-year-old fossilized cycad cone in Silverado Canyon, California, revealing that ancient cycads were far more diverse than their modern descendants. Previously thought to be “living fossils” that had remained largely unchanged since the dinosaur era, cycads now appear to have undergone significant evolutionary changes during the Cretaceous period. The find, assigned to a new genus called Skyttegaardia, highlights how much more dynamic and complex cycad history may be than once believed.
Cycads are cool to look at and examine closely, and it turns out that one of the best places in the United States to see actual living cycads in Descanso Gardens in La Canada Flintridge. But how’d they get there?
In 2014, La Canada Flintridge residents Katia and Frederick Elsea called the city’s Descanso Gardens with an odd proposal: would the famous horticultural center take their collection of over 180 rare cycads, a fern-like plant from the days of the dinosaurs?
The garden said yes, and now those plants are part of an effort to recreate a prehistoric landscape. Sixty-six species were transplanted from the Elsea collection to the garden’s Ancient Forest. Cycads form the heart of the forest, but there are also Tree ferns, with feathery fronds, and Ginkgo biloba, known for its distinctive fan-shaped leaves. This area, dedicated to showcasing some of the world’s oldest and most primitive plant species, highlights the remarkable resilience and beauty of plants that have survived for millions of years.
Cycads are a type of gymnosperm. Gymnosperms are a group of seed-producing plants that includes cycads, conifers, ginkgoes, and gnetophytes. Unlike angiosperms (flowering plants), gymnosperms do not produce flowers or fruits; instead, their seeds are exposed or “naked,” typically held in cones or on the surface of scales. They also have a unique structure, with a large crown of stiff, fern-like leaves arising from a stout trunk. They may look like palms or ferns, but they are actually their own distinct group of plants, with over 300 species in the world.
In contrast, flowering plants have been far more evolutionary successful. Angiosperms dominate most of the planet’s ecosystems, with an estimated 300,000 species, vastly outnumbering the gymnosperms. Their ability to form flowers and fruits has allowed them to diversify into nearly every terrestrial habitat on Earth.
Cycad cone (Dioon edule) at Descanso Gardens. Built for an ancient world: Cycad cones are among the largest and oldest seed structures on Earth, evolving long before the first flower bloomed. Their rugged design helped cycads thrive alongside dinosaurs — and survive into the modern day. (Erik Olsen)
The cycads at Descanso Gardens come from all over the globe, including Africa, Australia, and the Americas. They are part of the International Palm Society’s Cycad Collection, one of the largest and most diverse collections of cycads in the world. The collection at Descanso Gardens features over 200 cycad specimens, including rare and endangered species.
One of the fascinating plants showcased in the garden is the Sago Palm (not actually a palm), Cycas revoluta, a dioecious species, meaning it has separate male and female plants. Male Sago Palms produce multiple cones at their center, releasing pollen that insects carry to the female plants. The female plants develop a single, large cone in the center, which contains seeds. When the pollen fertilizes these seeds, a new plant can grow, continuing the cycle of this ancient species.
Another fitting addition to the Ancient Forest is the monkey puzzle tree, Araucaria araucana. This small, spiky tree is entirely covered with sharp, scale-like leaves that resemble thick, dense pine needles but are much tougher. Known as one of the earliest living conifers, the monkey puzzle tree stands as a living relic from the time when these ancient trees dominated prehistoric landscapes.
Cycads are fascinating not just for their ancient history, but also for their unique biology. Unlike most plants, which have a single apical meristem (a region of cell division at the growing tip), cycads have multiple meristems, which allows them to produce new leaves even if the growing tip is damaged. They also have a symbiotic relationship with cyanobacteria, which live in their roots and fix nitrogen from the air, allowing the plant to grow in nutrient-poor soils.
Despite their ancient origins, cycads are facing modern-day threats. Many species are endangered due to habitat loss and over-collection for the horticultural trade. The cycad collection at Descanso Gardens is not just a beautiful display, but also an important conservation effort to preserve these ancient plants for future generations.
Cycad at Descanso Gardens (Erik Olsen)
At Descanso Gardens, the cycads have been planted according to the geographic region where they originate: Africa, Asia, Madagascar, Australia and Mexico. Some of the plants no longer exist in the wild.
“For a really long time, this was plant life on Earth,” the former director, David R. Brown told the Los Angeles Times. “This helps remind me that, for as self-absorbed as we are often, we’re but a part of a story that has been going on for a very, very long time.”
If you’d like to learn more about Descanso Gardens, it’s collections and how it came into being check out this episode of Lost LA. And if you’re interested in seeing the cycad collection at Descanso Gardens for yourself, try visiting during the late afternoon, when the golden hour light heightens the beauty and mystery of these cool plants.
