Octopuses are already odd enough — eight arms, no bones, a brain that wraps around their throat — but one detail still stops people in their tracks: they have three hearts. Not two. Not one. Three.

And the reason is surprisingly practical.

Three Hearts for a Tough Life Underwater

Two of the hearts — called branchial hearts — do a very specific job: each one pushes blood through a gill, where it can pick up oxygen. The third, the systemic heart, takes that oxygen-rich blood and pumps it to the rest of the body.

In other words: two hearts to breathe, one heart to live.

Why Their Blood Is Blue

Another strange thing: their blood isn’t red at all.

It’s blue — literally blue — because it’s based on copper, not iron.

The copper-based protein, hemocyanin, works better in the cold, low-oxygen parts of the ocean where many octopuses live. It keeps them alive in places where most animals wouldn’t last a minute. But it’s not very efficient, so their bodies need extra pumping power to keep the oxygen flowing.

Evolution’s answer? Give them more hearts.

A Heart That Stops When They Swim

Here’s the part that sounds almost fictional: when an octopus swims, its main heart actually stops.

Imagine going for a swim and your heart taking a break halfway through. That’s why octopuses prefer to crawl on the seafloor. Swimming is simply too tiring — it literally costs them heartbeats.

The Ocean’s Quiet Genius

When you combine all of this — the blue blood, the three hearts, the bizarre nervous system, the ability to vanish into their surroundings — you get one of the most unusual and surprisingly intelligent creatures on the planet.

Octopuses don’t just survive in harsh oceans; they’ve evolved in ways that feel almost alien. And maybe that’s why we’re endlessly fascinated by them — they remind us how strange and creative life can be.

When an earthquake strikes, we experience its violent shaking on the surface. But new research from MIT shows that most of a quake’s energy actually goes into something entirely different — heat.

Using miniature “lab quakes” designed to mimic real seismic slips deep underground, geologists at MIT have, for the first time, mapped the full energy budget of an earthquake. Their study reveals that only about 10 percent of a quake’s energy translates into ground shaking, while less than 1 percent goes into fracturing rock. The vast majority — nearly 80 percent — is released as heat at the fault, sometimes creating sudden spikes hot enough to melt surrounding rock.

“These results show that what happens deep underground is far more dynamic than what we feel on the surface,” said Daniel Ortega-Arroyo, a graduate researcher in MIT’s Department of Earth, Atmospheric and Planetary Sciences, in a media statement. “A rock’s deformation history — essentially its memory of past seismic shifts — dictates how much energy ends up in shaking, breaking, or heating. That history plays a big role in determining how destructive a quake can be.”

The team’s findings, published in AGU Advances, suggest that understanding a fault zone’s “thermal footprint” might be just as important as recording surface tremors. Laboratory-created earthquakes, though simplified models of natural ones, provide a rare window into processes that are otherwise impossible to observe deep within Earth’s crust.

MIT researchers created the “microshakes” by applying immense pressures to samples of granite mixed with magnetic particles that acted as ultra-sensitive heat gauges. By stacking the results of countless tiny quakes, they tracked exactly how the energy distributed among shaking, fracturing, and heating. Some events saw fault zones heat up to over 1,200 degrees Celsius in mere microseconds, momentarily liquefying parts of the rock before cooling again.

“We could never reproduce the full complexity of Earth, so we simplify,” explained co-author Matěj Peč, MIT associate professor of geophysics. “By isolating the physics in the lab, we can begin to understand the mechanisms that govern real earthquakes — and apply this knowledge to better models and risk assessments.”

The work also provides a fresh perspective on why some regions remain vulnerable long after previous seismic activity. Past quakes, by altering the structure and material properties of rocks, may influence how future ones unfold. If researchers can estimate how much heat was generated in past quakes, they might be able to assess how much stress still lingers underground — a factor that could refine earthquake forecasting.

The study was conducted by Ortega-Arroyo and Peč, along with colleagues from MIT, Harvard University, and Utrecht University.

Our immune system’s largest antibody, IgM, has revealed a hidden superpower — it doesn’t just latch onto harmful microbes, it can also act like a brace, mechanically stabilizing bacterial toxins and stopping them from wreaking havoc inside our bodies.

A team of scientists from the S.N. Bose National Centre for Basic Sciences (SNBNCBS) in Kolkata, India, an autonomous institute under the Department of Science and Technology (DST), made this discovery in a recent study. The team reports that IgM can mechanically stiffen bacterial proteins, preventing them from unfolding or losing shape under physical stress.

“This changes the way we think about antibodies,” the researchers said in a media statement. “Traditionally, antibodies are seen as chemical keys that unlock and disable pathogens. But we show they can also serve as mechanical engineers, altering the physical properties of proteins to protect human cells.”

Unlocking a new antibody role

Our immune system produces many different antibodies, each with a distinct function. IgM, the largest and one of the very first antibodies generated when our body detects an infection, has long been recognized for its front-line defense role. But until now, little was known about its ability to physically stabilize dangerous bacterial proteins.

The SNBNCBS study focused on Protein L, a molecule produced by Finegoldia magna. This bacterium is generally harmless but can become pathogenic in certain situations. Protein L acts as a “superantigen,” binding to parts of antibodies in unusual ways and interfering with immune responses.

Using single-molecule force spectroscopy — a high-precision method that applies minuscule forces to individual molecules — the researchers discovered that when IgM binds Protein L, the bacterial protein becomes more resistant to mechanical stress. In effect, IgM braces the molecule, preventing it from unfolding under physiological forces, such as those exerted by blood flow or immune cell pressure.

Why size matters

The stabilizing effect depended on IgM concentration: more IgM meant stronger resistance. Simulations showed that this is because IgM’s large structure carries multiple binding sites, allowing it to clamp onto Protein L at several locations simultaneously. Smaller antibodies lack this kind of stabilizing network.

“This synergistic bracing action gives IgM a unique advantage in neutralizing bacterial toxins that are exposed to mechanical forces inside the body,” the researchers explained.

The finding highlights an overlooked dimension of how our immune system works — antibodies don’t merely bind chemically but can also act as mechanical modulators, physically disarming toxins.

Such insights could open a new frontier in drug development, where future therapies may involve engineering antibodies to stiffen harmful proteins, effectively locking them in a harmless state.

The study suggests that by harnessing this natural bracing mechanism, scientists may be able to design innovative treatments that go beyond traditional antibody functions.