The halting of human bone growth helps manage heat produced from metabolism

Environment and genetics explain why animals have widely different lifespans

Both environmental conditions and genetic factors shape how long various animals live. For some creatures, colder conditions allow for less energy use and slower aging. Larger animals have fewer predators. While humans don't live the longest, we are a rare species that successfully lengthened its average lifespan over time.

Cells cannot grow forever due to escalating inefficiency in transporting chemicals

As cells get larger, their volume grows much faster than the surface area through which nutrients and waste products pass, creating a bottleneck that eventually causes cells to die. This forces nearly all organisms visible to the naked eye to comprise enormous numbers of smaller cells, such as the approximately 30 trillion found in the average adult human.

Air sacs and lightweight bones helped some dinosaurs grow to enormous sizes

After the Triassic extinctions, new species with birdlike anatomy evolved from smaller, early dinosaurs. This anatomy allowed for more efficient breathing and lighter skeletons, favoring the evolution of larger organisms.

How snake biology allows them to eat prey larger than they are

Possessing flexible skulls with elastic ligaments and unfused jaw bones, snakes can open their mouths to engulf much larger prey, and adjustable airways enable them to continue breathing while their teeth grip onto their food. Through slow digestion and specialized cells that decompose bones, some snakes can survive on a single large meal for over a year.

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.

Plant hormones and growth regulators guide growth stages and responses in plants

Plants naturally produce hormones like auxin and gibberellins, while humans apply synthetic or extracted growth regulators to control plant development. These substances influence processes like flowering, root growth, dormancy, and ripening—even in very small doses.

Resistance training can help fight osteoporosis, especially in menopausal women

Weight-bearing training that pulls on bones, joints, and muscles can strengthen bone health. Movements like squats, rows, shoulder and chest presses, and push-ups can be started at any age (if you don't already have advanced bone loss), though ideally they should be started earlier—in one's teens or young adulthood—to stave off bone density losses that begin in your 30s.

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

Humanity's reduced body hair slows down wound healing

Cuts to human skin take twice as long to heal compared to chimps and other mammals. Scientists argue this is due to the reduced number of hair follicles on human bodies. Hair follicles contain stem cells which help repair skin cells faster, so as humanity shed its hair over time, so to speak, it also slowed its wound healing.

Humans aren't the only mammals who go through menopause, but it's rare in the animal world

While scientists are unsure how many mammals actually experience menopause, they do know for sure that humans aren't the only ones. Orcas and some toothed whales (like belugas and narwhals) go through menopause. And a recent study found chimpanzees also experience the condition, though it's late in life.

Why hibernating bears don't get blood clots

For mammals, long periods of inactivity can lead to health problems—blood flow slows and pools, veins kink and distort, and clots potentially form. Hibernation takes this risk to the extreme, yet for decades why animals like bears did not exhibit...

Gender-affirming hormone therapy cues changes similar to puberty

When HRT is part of gender affirmation care, people receive regular doses of estrogen or testosterone to alter hormone levels to more closely align with those of cis individuals of that biological sex. HRT may affect voice pitch, body hair, bone density, and more. Many of those changes are not reversible with the cessation of therapy, though the effects may diminish.

Your feet can expand—permanently—due to pregnancy

A hormone called relaxin loosens tissues in the body to allow them to expand during pregnancy, affecting muscles and body parts—including the feet. The structural changes that occur in the foot as it expands are sometimes permanent. This article states that researchers have found as many as 61% of new moms did not have their foot sizes return to their prepregnant state. (Some users may encounter a paywall.)

The Turritopsis dohrnii jellyfish can reverse its life cycle

Discovered in the 1980s, this creature has been dubbed the "immortal jellyfish" for its ability to revert from medusa to polyp form and back, preventing it from dying of old age. However, the jellyfish remains prey to fish and turtles and is defenseless to sea slugs as a polyp.

Gastroliths, or ‘stomach stones,’ help animals digest plants in their stomachs

Most often used by birds and reptiles, gastroliths help break down the cellulose of plant cells, which can resist decomposition from stomach acid alone. Over time, gastroliths become smooth and are regurgitated before being replaced by larger stones.

Limb regeneration research may lead to treatments for arthritis

For scientists pursuing the cure for arthritis, the holy grail of discoveries lies in how to regrow healthy cartilage inside human joints. While this feat has so far resisted our best scientific attempts, there are plenty of other human tissues—such as the liver and fingertips—that will successfully regenerate.

Human anatomy 101: the body's systems

Human life is made possible by the body's ten major systems, which maintain homeostasis by responding to incoming sensory and biochemical input. Each system must work independently and collaboratively for the body to maintain health and respond appropriately to its internal and external environments. The bones of the skeletal system, for example, give the body its shape and protect organs while also facilitating movement with the muscular system.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

'Artificial embryos': The hidden steps in forming a spine

Somitogenesis is the process by which segmented body structures like vertebrae form in embryos. While the process is well understood in animals like mice or zebrafish it is difficult to study in humans. But now, researchers have created a model of somitogenesis, using pluripotent stem cells, called an axioloid.

Rising sea levels due to climate change may be slowing Earth's rotation

A 2024 PNAS study found that from 2000 to 2020, the length of a day increased at a rate of 1.33 milliseconds per century, an unprecedented amount in the 3.6 million years of day-length changes reconstructed from an analysis of benthic foraminifera fossils. Researchers suggest the slowing comes from changing ice sheets redistributing planetary mass.

'Human composting' is an eco-friendly burial method legal in only a few states

Formally known as natural human organ reduction, this process relies on the same principles as standard composting and breaks down the body over many weeks, turning it into a type of soil. It's currently only legal in a handful of states.

Physiological muscle memory allows us to quickly regain lost musculature

The term "muscle memory" is most often associated with the neurological kind, which involves the development of strong and efficient neural pathways in the brain and spine. Physiological muscle memory also slows the loss of muscle mass, with both types affected by genetics and diet.

Tech entrepreneur Bryan Johnson's mission to live forever

Johnson has invested millions of dollars into developing a biohacking program he believes will extend his life beyond typical expectations, relying on medical professionals to reduce his "biological age." Most notably, he drew significant public attention with reports of blood-swapping with his teenage son.

Girls are hitting puberty earlier than ever before

Around the world, there has been a spike in children—especially girls—experiencing early puberty and doctors are seeking to understand why. The rise has been particularly strong post-2020. Early-maturing girls are at a higher risk for developing...

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

Deep sea fish rely on a molecular strengthener to prevent being crushed

Trimethylamine N-oxide (TMAO) stabilizes hydrogen bonds and prevents water and proteins within organisms from being misshapen under immense pressure. Compounds called piezolytes protect cellular membranes from being crushed in regions like the Mariana Trench, where pressures are 1,100 times greater than surface atmospheric pressure.

Sleep deprivation may slow metabolism

This article explains that, according to research from Penn State, restricting sleep for just a few days can affect how the human body metabolizes fats and change how satisfied people feel after a meal. The study found that people who don’t get...

More extreme heat days are putting human health at risk in both the short and long term

America is generally experiencing more frequent extreme heat days, over a longer period, in certain parts of the country. The heat-related death toll is rising, and beyond those direct deaths, extreme heat can also have troubling ripple effects including elevated violence and decreased productivity.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

Fish populations in the Great Barrier Reef have increased after installing waterproof speakers on the ocean floor that played recordings of sounds from healthy coral reefs.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Scientists testing how climate change affects plants found, in a years-long simulation study, that poison ivy grew 70% faster with the resulting extra carbon dioxide.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

Recent research found that the brain doesn't seem to massively rewire following amputation—upending earlier beliefs about the cause of phantom limb pain.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

For centuries, it was common to sleep in two shifts: a few hours at the beginning of the night, and a longer period beginning around midnight

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.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

US housing costs have risen by roughly 175% between 1991 and 2026—but a growing number of Gen Zers are becoming homeowners anyway. In 2025, 4% of homebuyers were Gen Z, up from 3% the year before.

NBA superstar Victor Wembanyama spent the 2025 summer training with monks in central China to enhance his body and mind.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

The distributor behind 'Rocky Horror' pulled the film from its scheduled national release, believing it would be a failure, though it eventually amassed a dedicated fanbase through midnight showings, a trend that continues over 50 years later.

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.

See how Budweiser's famous Clydesdales spend their days at Warm Springs Ranch, where roughly 70 to 80 of the beer brand's giant horses can be found at any given time.

Hedge funds, the private investment firms that trade a wide swath of financial assets, make money by imposing steep fees on investors and from the fund's investment performance.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.