Bats are uniquely suited to act as reservoirs of viruses

Bats have evolved to carry viruses without getting sick

Bats—the likely animal reservoir for diseases including Ebola and coronavirus—tolerate viruses without getting sick. The secret lies in evolutionary adaptations allowing bats to become the world’s only flying mammal and to thrive under immense physiological stressors.

Ebola's natural reservoir species are likely bats

But the virus doesn't seem to sicken the animals, so capturing an infected bat and performing necessary tests has remained challenging. Though many scientists believe fruit bats are the reservoir species for the virus, Ebola viral RNA fragments were detected in a greater long-fingered bat captured in 2016 in Liberia. The species isn't a fruit bat—it roosts in caves and feeds on insects. The scientist behind the discovery states that he believes the virus likely infects multiple host species and that the hosts may differ regionally. (Some users may encounter a paywall.)

Using mosquitoes to vaccinate bats could curb the spread of deadly diseases

Researchers in China tested a transmissible rabies vaccine in the lab by feeding mosquitoes blood containing the vaccine and observing what happened to bats when they were either bitten by the mosquitoes or fed on them. The bats developed antibodies against rabies and survived subsequent rabies infection. (Some users may encounter a paywall.)

Scientists have struggled to pin down Ebola's natural reservoir species for decades, but the available evidence suggests that it's very likely fruit and insect-eating bats found in Africa.

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa

More than 70% of all new infectious diseases originate in animals. Referred to as zoonotic diseases, these are diseases that originate in animals and occasionally spill over or jump from animals to humans. Bats, mosquitoes, and primates have all been linked to spillover events. As human populations push further into previously uninhabited wilderness, animal-human contact increases, and disease spillover is inevitable.

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa.

Vector-borne diseases kill more than 700,000 people globally each year—and are growing

The diseases with the greatest potential to spread widely aren't the ones that quickly kill human hosts. Instead, the best hosts or reservoirs for vector-borne diseases would be chronically ill over the long term, increasing the likelihood that the pathogen could be transmitted to others.

Vampire bats are the only mammal to feed exclusively on blood

Scientists believe their ancestors may have eaten parasites and insects off larger animals until vampire bats started feeding directly from those animals. Colonies work together to stay fed, as a vampire bat can die without just two days of eating.

Rabies kills more than 50,000 worldwide each year

Rabies transmission to humans typically comes from an infected animal, and death was very common before recent protocols were developed (post-exposure prophylaxis). The virus is neurotropic, which means it has an affinity for nerve tissue, and moves quickly from broadly infecting the body to destroying the brain.

Some North American bats can glow in the dark

After examining 60 museum specimens from six different species, scientists found that all of them emitted light after being exposed to ultraviolet radiation. Researchers are perplexed by this natural phenomenon and are currently unable to deduce the reason behind it.

Explore 3D models of some of the most dangerous viruses

Everyone has come in contact with common viruses—typically something like influenza (the common flu)—but sometimes they encounter more dangerous strains. While we're familiar with the symptoms that manifest, it wasn't until the advent of advanced microscopy that scientists could pin down the exact structure and behavior of various viruses.

Robins are a major host for West Nile in North America

Explore this interactive with key details and interesting facts about the disease, including that Culex genus mosquitoes are the main US vector for its spread, and that certain species—American crows and blue jays—are quite infectious with the disease, while American robins—despite being a significant host for the virus in North America—are less infectious.

Some mosquitoes are key pollinators—and eat disease-carrying mosquitoes

​​There are more than 3,500 species of mosquitoes, and only a small fraction of them bite humans. They also play vital roles in the ecosystem: One young elephant mosquito, for example, can eat dozens of smaller mosquitoes that bite humans in just one day. Sometimes mosquito-gobbling species are released by humans to control other mosquitoes.

Seven known types of coronaviruses have jumped from animals to humans

Coronaviruses, including SARS-CoV-2, belong to a large family of viruses characterized by their crown-like appearance under a microscope, due to spike proteins on their surface. While thousands are believed to exist in animals, only seven are known to have made the jump to humans.

The bats that live in and protect Portugal's libraries

Two 18th-century libraries in Portugal, the Joanina Library at the University of Coimbra and the Library at the National Palace of Mafra, are home to colonies of bats. These bats are welcome guests because they eat insects that could damage the manuscripts. Visitors can try to see the bats emerge at nightfall in Coimbra or visit on a rainy day and hear them. While catching a glimpse of the bats in Mafra is difficult, the library displays taxidermied remains of former residents.

Watch an expert's take on the rare disease hantavirus—and why it's not of great concern to the general population

This rare zoonotic disease, transmitted to humans primarily through infected rodent droppings, urine, or saliva, is rarely spread between people. The disease was of particular concern in spring 2026, when an outbreak occurred on a 150-person cruise ship, prompting a flurry of action, including contact tracing for passengers in their home countries. The disease can be fatal. But early care—primarily oxygen support—can help patients survive.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

Humans are the only known reservoir of poliovirus

The virus has not been found in any other species, which makes humans the only known reservoir for polio. In laboratory settings, nonhuman primates have also been infected with the virus, but there's no evidence that they contract the virus in nature.

Marburg virus, related to Ebola, is also extremely deadly, and has no available vaccine.

Simulation of the coronavirus inside an aerosol droplet

A new simulation shows how the virus survives inside tiny airborne particles of water — and gives clues about how the Delta variant became dominant.

Some animals may anchor their brain cells to specific landmarks to determine direction

In a study of bats exploring a new area, specific sets of "head direction cells" were seen becoming active based on bats' orientation when moving, and this activity became more coordinated over time. Researchers suspect, like humans, bats and other animals establish this sense of direction based on movement relative to known points of interest.

Receptors on the cell surface are key to whether a virus is successful

Viral receptors are key regulators of host range, tissue tropism, and viral pathogenesis—basically, the door locks on cells allowing viruses to invade, if they have the right key. How this process works at the microscopic level determines whether a virus is able to trigger a widespread illness in the host.

Horses account for about 96% of the known mammalian cases of West Nile beyond humans

That's partly because horse owners likely notice and take veterinary action when their animals get sick. There is no way to know how frequently wild animals are getting infected with the virus.

Superbugs evolve defenses against medication, then share them with neighbors

One reason antibiotic resistance spreads so quickly is that bacteria have multiple mechanisms allowing them to share genetic material. This short video offers a concise explanation for each of these mechanisms, and animation that helps viewers understand how antimicrobial resistance can quickly spread from one organism to another.

HFMD can survive on surfaces for days at a time

That's why the virus can be transmitted via fomites—surfaces that have virus on them like doorknobs, kids toys, etc. These viruses are resilient—they are often even resistant to freezing (and are frequently stored at freezing temperatures in lab settings).

Model organisms like yeast, mice, and flies help scientists decode the human body

Some species are used to quickly study the effects of human diseases and treatments because they are short-lived and have similar systems to those found in humans. Bacteria, like E. coli, have been used as human proxies given their rapid growth and ease of genetic manipulability.

Mammals thrived under the feet of dinosaurs

An explosion of fossil finds reveals that ancient mammals evolved a wide variety of adaptations allowing them to exploit the skies, rivers and underground lairs.

Cold-blooded reptiles seek heat, and that behavior may help combat fungal infections

This Radiolab podcast episode takes on the idea that though our human bodies are too warm for the majority of fungal species to effectively replicate inside our bodies, that's not the case for reptiles. Yet when those species warm their bodies by basking in the sun on rocks, they can soak up heat and may also help keep fungal infections in check.

The economics of horseshoe crab blood

Horseshoe crabs are older than dinosaurs and have survived five mass extinctions that wiped most life from the planet. But it's only now that their future as a species is in danger. This blood, worth about $60,000 per gallon, is hyper-sensitized to certain bacteria that are fatal to humans. This 17-minute podcast dives into humanity's pursuit of horseshoe crab blood, a "somewhat magical" mixture heavily relied on by the pharmaceutical industry.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

Explore the animals that populate the depths of the ocean, from fish and coral in the first few hundred feet, all the way down to the bottom of the Mariana Trench.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

Animal phobias are likely the most common type of phobias, followed by an extreme fear of heights.

The American cockroach is actually from Africa, an apparent hitchhiker aboard ships carrying enslaved people, with evidence suggesting the bug may have arrived in the New World as early as the 1600s.

Tattoos remain visible on your skin thanks to immune cells called macrophages

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

View the ten deadliest tornadoes in US history.

Hurricanes, which rely on air consistently spinning in the same direction, cannot cross the equator because air curves in opposite directions north and south of it.

Venture capital is a form of funding provided to early-stage companies with high growth potential, typically in exchange for an equity (or ownership) stake

Poison ivy's characteristic rash is caused by an allergic response to an oily compound in the plant called urushiol.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Hotels in Cannes, the glamorous city on the French Riviera, hire hawks to ward off seagulls during the city's famous film festival.

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.