8 award-winning photos of nature’s stranger things

The California Academy of Sciences brings us sperm clouds and happy stoats with its yearly photo competition.
Starfish spawning in water
Leach's sea star. Tony Wu/BigPicture Photography Competition

This gallery was originally published in bioGraphic, an independent magazine about nature and conservation powered by the California Academy of Sciences, and media partner of the BigPicture Photography Competition.

In a time when biodiversity is taking hits from all sides, whether it be climate change, human development, or pestilence, the California Academy of Sciences’ BigPicture Photography Competition both celebrates wildlife and brings the many issues it faces to the fore. This year’s winners and finalists span everything from the “insect apocalypse” to predator-people conflicts to fascinating mating behaviors. Here are our favorites from the judges’ savvy choices (we’ll never turn down the chance to share a good bee orgy). —PopSci editors

[Related: 7 animal mating rituals that make horseshoe crab orgies look tame]

Aquatic Life Finalist (above)

Three days before the full moon last July, photographer Tony Wu dove into a bay off the coast of Kagoshima, Japan, in search of a starry goby (Asterropteryx semipunctata)—a golf-tee-sized fish with bright, pin-prick dots scattered across its dark skin. He had been hoping to photograph the pretty, star-studded fish for weeks, and he expected to spend his whole dive focused on that task. But shortly after he spotted his first goby, Wu got sidetracked by a different stellar scene: A Leach’s sea star (Leiaster leachi) raised itself up onto the tips of its arms and began to spawn, shooting a Milky Way of sperm into the surrounding seawater.

Like many marine invertebrates, starfish reproduce by broadcast spawning—releasing large quantities of sperm and eggs into the water column within a short period of time. To maximize the chances of fertilization for these gametes, they synchronize their efforts with neighboring members of their species, using temperature, light, and lunar cycle cues to guide their timing.

Wu watched this particular starfish spawn for at least an hour. “At some point, I realized that the animal was not sending out gametes willy-nilly,” he says. “It timed its release of sperm for certain moments, perhaps as a reaction to current flow and strength.” As its gametes drifted off into the distance, he reflected on the experience of sharing such an intimate moment with a faceless, spineless creature. “I hope that capturing a dramatic scene depicting this species’ timeless quest for immortality can provide a way for others to see what I see—that we are all the same, despite our outward differences.”

Grand Prize Winner

Female cactus bee being wrestled by male mates on the sand
Cactus bees. Karine Aigner/BigPicture Photography Competition

On a warm spring morning in South Texas, a female cactus bee (Diadasia rinconis) emerged from her small, cylindrical nest in the ground, rising like ash from a chimney. Almost instantly, she was swarmed by dozens of patrolling males, their tawny bodies forming a buzzing, roiling “mating ball” as they vied for a chance to copulate with her. After a tumultuous 20 seconds or so, the ball of bees dissipated, and the female flew off—a single, victorious male holding tight to her back.

Because they make individual nests rather than living in a collective hive, cactus bees are considered solitary. However, the designation is somewhat misleading; the bees nest in close proximity to one another, and their mating aggregations can number in the thousands—a spectacular, highly charged sight for any lucky human observers. “Mating in the bee balls often takes place on extremely hot, bare ground,” says entomologist Avery Russell from Missouri State University, “so the grappling males might risk cooking themselves [to mate].” They also face stiff competition. “The sex ratio in this species is often wildly lopsided, with single females emerging occasionally, dozens of patrolling males finding her in seconds, and potentially thousands of males flying overhead,” he adds.

Mating aggregations only last for a little more than a week, so photographer Karine Aigner was fortunate to capture this particular mating ball. While rarely noticed or documented by humans, these native bees play a critical role as pollinators, especially for prickly pear (Opuntia spp.) cacti, a critical source of sustenance for many species in the dry American Southwest.

Terrestrial Life Finalist

White stoat leaping above the snow with its mouth open
Stoat. Jose Grandío/BigPicture Photography Competition

In the pre-dawn hours of a cold winter morning in the French Alps, photographer Jose Grandío lay still in the snow, waiting for a stoat (Mustela erminea) to emerge from its burrow. He had spent the past few days waiting in the same manner, without payoff, but his patience was about to be rewarded. Shortly after the sun rose, the stoat climbed out into the pale, winter light and proceeded to put on a spectacular show. “He seemed to be playing with the fresh snow that had just fallen, making sudden jumps and crawling through the snow,” recalls Grandío.

Scientists have witnessed stoats engaging in similar displays on many occasions, and they refer to the behavior as dancing, although their opinions are divided about what motivates the leaps and twists. Sometimes, the dances are performed in front of a rabbit or large bird in a seeming attempt to confuse or distract potential prey—a strategy that has proven effective in a number of documented interactions. At other times, as was the case in the display Grandío photographed, there is no prey animal in sight, and the dance seems simply to be an expression of exuberance. A third hypothesis is that the dances are actually an involuntary response to a parasitic infection, since stoats are known to be hosts for cranial parasitic worms. Whatever the interpretation of the behavior, one thing scientists have learned is that when associated with an attack on a large prey species, these displays reduce the risk of injury to the stoat—likely because they provide an element of surprise. Such a benefit could eventually reinforce the behavior, whether it was originally intentional or not.

In this particular case, the stoat leapt and danced for about half an hour before returning to his den for the rest of the day. While the impetus for his energetic display is unclear, Grandío can’t help thinking it was “something like a game for him,” a joyful response to the pleasure of pristine snow.

Human/Nature Finalist

Jaguar snarling at pigs in a pen
Jaguar and domestic pigs. Fernando Constantino Martínez Belmar/BigPicture Photography Competition

Two creatures face off through a woven-wire fence: one predator the other prey; one wild, the other, essentially, manufactured for our use. The moment is a manifestation of two worlds colliding, with no clear indication of which will prevail. Such images, of the natural world intersecting with one so heavily impacted by humans, have become a near obsession for Mexico-based photographer Fernando Constantino Martínez Belmar. And few places in the world present as many opportunities to capture the conflict first-hand as Martínez Belmar’s native Yucatán Peninsula, home to both the elusive jaguar (Panthera onca) and one of Mexico’s fastest-growing tourist hotspots, the “Maya Riviera.”

The largest predators in the neotropics, jaguars require a significant amount of space in order to find sufficient prey—the average home range of a male jaguar spans some 100 square kilometers (38 square miles). Inevitably, as human populations have expanded into the jaguar’s habitat, the species’ distribution has shrunk by more than half. Scientists are now working to identify conservation strategies and priorities to best support the remaining population. In Mexico, one of the most important regions of focus is the state of Quintana Roo on the Yucatán Peninsula, which is home to nearly half of the country’s 4,000 – 5,000 jaguars. Here, the cats are thriving in two protected areas: Yum Balam on the northern tip of the peninsula and Sian Ka’an some 225 kilometers (140 miles) to the south. Between the two reserves sit Cancún, Playa del Carmen, and Tulum.

Until recently, scientists had little hope that a viable ecological corridor could exist between the two protected areas, given the heavily developed land that links them. However, a radio tracking study published earlier this year suggests that jaguars are not only using this corridor—they are establishing home ranges along its route. While the cats prefer forested or secondary growth areas over profusely disturbed habitat, they are capable of capitalizing on opportunities presented by human development. One male, for instance, centered his home range on a landfill, where he found a plentiful source of prey in the form of feral dogs and other animals that scavenged at the site. It’s not an ideal scenario, but the resilience demonstrated by these individuals provides hope that with thoughtful planning around future development in the area, the Yucatán Peninsula’s jaguars can continue to thrive.

Art of Nature Winner

Dead insects collected from a light on a white background
Insect species. Pål Hermansen/BigPicture Photography Competition

When photographer Pål Hermansen walked outside one brisk March morning in Ski, Norway and looked back at his house, he was dismayed. One of the outdoor lights had been left on all night, and within its bright shell, he saw the dark stains of dozens of insects, drawn to their death by the accidental beacon. As he cleaned out the fixture, Hermansen was inspired to photograph the collection of insects, hoping to shine a light on “the hidden creatures that are a foundation for our lives—creatures that we easily ignore.”

Insects are the most diverse group of organisms on Earth—scientists estimate that up to 30 million species currently exist. They are also staggeringly abundant, comprising more than half of the biomass of all animals on the planet. However, while insects still far outnumber other groups of animals, their populations have plummeted in recent decades. A 2019 paper analyzing the status and causes of these declines used the phrase “death by a thousand cuts” to summarize the crisis; climate change, deforestation, agricultural conversion, urbanization, pollution, and introduced species have all taken a toll on the planet’s insects.

While too often viewed as pests, insects perform a number of valuable functions for humans, including crop pollination, soil aeration, nutrient recycling, and disease control. They are also a critical food source for a wide variety of other species, many of which we also rely upon. As insect numbers dwindle, the potential for significant ecological and economic consequences grows. But a deeper public understanding of the decline and its ramifications may help to turn the trend around. The artfully arranged contents of Hermansen’s unintentional light trap serve as a reminder of both the plight—and the value—of these oft-unheralded inhabitants of our planet.

Aquatic Life Finalist

Dead sea lion covered in bat stars on the ocean floor
California sea lion and bat stars. David Slater/BigPicture Photography Competition

Each year, from August to early October, Atlantic goliath groupers (Epinephelus itajara) gather off the east coast of Florida to spawn. On dark nights when the moon is new, refrigerator-sized males produce low-frequency booming sounds by contracting their swim bladders, calling other groupers to congregate around shipwrecks or rocky reefs. Fifty years ago, more than 100 fish might answer the call. But by 1990, the slow-moving species had been fished almost to extinction, and mating aggregations were often reduced to just a handful of fish. That year, goliath groupers were protected under both federal and state fishing bans, and the population slowly began to recover. While Florida’s mating aggregations have not yet attained the numbers local fishermen recall from the 1970s, it’s now common to see 20 to 40 groupers together during the breeding season.

Photographer and coral reef ecologist Tom Shlesinger has witnessed this spectacle many times in recent years, but swimming with these 800-pound gentle giants never gets old. During one dive last September, he watched, captivated, as a large male swam calmly through a huge, swirling school of round scads (Decapterus punctatus). “It looked like he was swimming through a tunnel of fish,” Shlesinger recalls, “and I immediately knew this was the perfect moment to capture a unique perspective.”

Shlesinger cherished the experience, partly because he knows the species is once again in jeopardy. In March, despite heavy opposition from scientists who study the species, the Florida Fish and Wildlife Conservation Commission voted to reopen recreational fishing for goliath groupers beginning in 2023. Under the new plan, up to 200 permits will be sold each year for between $150 and $500, each of which will allow for the harvest of an adult grouper.

Goliath grouper experts Felicia Coleman and Chris Koenig from Florida State University have produced a litany of reasons why the decision is ill-advised, not least of which is that the population isn’t currently as stable as it might seem. While the number of juvenile groupers has increased in recent years, the number of breeding adults has actually declined, likely due to poaching and habitat degradation. Moreover, from an economic perspective, goliath groupers are worth much more alive than dead. As the mating aggregations have grown, a thriving ecotourism business has sprung up around them, generating revenue that far exceeds the price of the fishing permits. Additionally, goliath groupers prey on species that would otherwise eat juvenile lobsters; healthy populations of the fish have been linked to more robust lobster harvests.

“Opening the fishery for this iconic species under the current circumstances seems quite shortsighted,” Shlesinger laments. There is hope, though, in what scientists have learned since 1990—that if measures are adopted to protect the species, it is capable of recovering.

Winged Life Winner

Indian fruit bat silhouette at night through leafy branches
Indian fruit bat. Sitaram May/BigPicture Photography Competition

Photographer Sitaram May used to think of wildlife photography as something he did while traveling. But when the COVID-19 pandemic swept the globe, he started to pay more attention to the wildlife in his own backyard. “One night, sitting on my balcony, I was looking out at a custard apple tree, and bats were coming frequently to eat the fruits,” he recalls. “The whole world was cursing bats, but I decided to observe them.” May spent three weeks watching the fruit bats, eventually learning to predict their behavior and identify gaps in the tree canopy where they were likely to make an entrance. At one such opening, he managed to capture this shot, perfectly framing the bat within a ring of lush, green foliage.

India is home to 12 species of fruit bats, all of which play a critical role in seed dispersal and forest regeneration. Because they are significantly larger than their Neotropical relatives, Indian fruit bats feed on a much wider range of flowers and fruits—from small eucalyptus flowers to large mangos and guavas—and are often responsible for the dispersal of old-growth and canopy tree species. A recent survey of their feeding habits revealed that the three most common species alone aid in the pollination and seed dispersal of more than 114 species of plants, many of which are economically, ecologically, and medicinally valuable.

While May developed a deep appreciation for fruit bats during his backyard observation sessions, the animals are often regarded as pests. Despite their ecological importance, 10 of the 12 species are classified as vermin under India’s Wildlife Protection Act and can be indiscriminately killed. Relatively little is known about fruit bat population levels in India, but surveys conducted by ecologist Shahroukh Mistry suggest that most species are dramatically declining. In the past, the animals lived in large colonies that often numbered in the thousands; today the average colony size is 500 or fewer. Additionally, more than 70 percent of the roosts Mistry visited faced some sort of threat, including deforestation and other human disturbances. To continue performing their valuable pollination and seed-dispersal roles in India, fruit bats need stronger protection—something a number of local conservation organizations are now lobbying the government to enact. 

Human/Nature Winner

Common frog spawning in water
Common frogs. Bence Máté/BigPicture Photography Competition

While traveling in Romania’s Carpathian region several years ago, photographer Bence Máté came across a horrific scene. At a spawning site for common frogs (Rana temporaria), hundreds of frogs (and several toads) lay dead in the water, some still grasping partners, their hind legs notably missing. Poachers had plucked the amphibians from the pool as they attempted to breed, cut off their back legs to feed the frog-leg trade, and thrown them back into the water to die a lingering death among their spawn. “It was the cruelty that shocked me most,” says Máté, “but also the harm caused to local populations.”

Every year, millions of frogs are traded around the world as a source of food. The trade is fueled not just by the collection of wild animals on a local scale, as Máté witnessed in Romania, but also by industrial commercial farming in China and other countries. While poaching can imperil local populations, commercial farming actually poses an even greater threat to amphibians around the world. “Mass farming and international trade to supply the frog-leg industry are spreading deadly diseases and contributing to the current amphibian extinction crisis,” says herpetologist and wildlife trade expert Jonathan Kolby. “Two types of pathogens in particular, amphibian chytrid fungus and ranavirus, are being spread far and wide by the trade in frog legs and have already driven dozens of population declines and extinctions.”

If frog legs are to stay on the menu for humans, improved welfare and disease control measures are urgently needed to better protect amphibians globally.