Slime Molds Can Remember Things Without a Brain

A picture taken on October 16, 2019 at the Parc Zoologique de
Paris shows a Physarum Polycephalum better known as a “Blob.”STEPHANE
DE SAKUTIN | AFP | Getty Images
A picture taken on October 16, 2019 at the Parc Zoologique de Paris shows a Physarum Polycephalum better known as a “Blob.”STEPHANE DE SAKUTIN | AFP | Getty Images
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Slime Molds Can Remember Things Without a Brain

A picture taken on October 16, 2019 at the Parc Zoologique de
Paris shows a Physarum Polycephalum better known as a “Blob.”STEPHANE
DE SAKUTIN | AFP | Getty Images
A picture taken on October 16, 2019 at the Parc Zoologique de Paris shows a Physarum Polycephalum better known as a “Blob.”STEPHANE DE SAKUTIN | AFP | Getty Images

A recent German study found that the slime mold - known as Physarum polycephalum or The Blob - seems to remember where it previously found sources of food even without a brain or nervous system.

P. polycephalum is one of the most peculiar forms of life on earth. It is not plant, animal, nor fungus, but a species of slime mold which lives in dark forests and enjoys damp and cool environments.

The creature wanders over dead plants with a significant speed eating all fungi, bacteria, and decomposed materials it may find in its way.

Early in its life cycle, P. polycephalum exists as a single cell with a single nucleus, but later it merges with other cells to form a huge single cell that looks like a yellow pool of mud.

Similar to the invincible creatures featured in The Blob thriller, P. polycephalum can reassemble its parts even after being ripped in pieces.

In 2000, Japanese researcher Toshiyuki Nakagaki discovered that P. polycephalum was capable of solving a simple maze to reach a food source.

Biological physicists Mirna Kramar and Karen Alim of the Max Planck Institute in Germany have discovered that this brainless, neuronless creature uses the very architecture of its body to store memories about where it has previously found food.

The body of this creature is composed of a complicated network of connected tubes. During a study that will be published on March 9, in the PNAS journal, the biological physicists found that when P. polycephalum discovers a source of food, it releases a chemical that locally softens the tube wall at the site of the food.

This then triggers the tubes to dilate, becoming wider, to expedite flow within the slime mold to the site. When it found and eaten a nutritious meal, those thick tubes remain in place so that it can quickly return to the site if food were to reappear.

P. polycephalum can reabsorb parts of its body if it stretches out exploratory tubes into a region that is inhospitable, or contains nothing of interest.

"This is not utterly dissimilar to how the human brain works. In this case, synapses, which send information between neurons, strengthen when we learn and grow stronger the more we use them, but can grow weaker if we don't - vaguely similar to the slime mold's tubes, which will grow thicker at sites of interest, but will die off or be reabsorbed if their presence is no longer useful to the organism," said researcher Karen Alim in a report published on March 1, on the Science Alert website.



Marseille Airport Suspends Flights Due to Wildfire as Public Warned to Stay at Home

 Smoke rises over Marseille as a fast-moving wildfire spreads on the outskirts the city, southern France, July 8, 2025. (Reuters)
Smoke rises over Marseille as a fast-moving wildfire spreads on the outskirts the city, southern France, July 8, 2025. (Reuters)
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Marseille Airport Suspends Flights Due to Wildfire as Public Warned to Stay at Home

 Smoke rises over Marseille as a fast-moving wildfire spreads on the outskirts the city, southern France, July 8, 2025. (Reuters)
Smoke rises over Marseille as a fast-moving wildfire spreads on the outskirts the city, southern France, July 8, 2025. (Reuters)

A wildfire spurred by hot summer winds reached France's second-largest city Tuesday, grounding all flights to and from Marseille, injuring at least nine people and forcing many residents to evacuate or barricade themselves indoors as smoke choked the Mediterranean air.

A big city hospital switched to generator power, train traffic was halted in most of the surrounding area, and some roads were closed and others tangled with logjams.

More than 1,000 firefighters were deployed to tackle the fire, which broke out near the town of Les Pennes-Mirabeau before racing toward Marseille. Some 720 hectares (acres) were hit by the blaze, the prefecture said.

Nine firefighters were injured, according to the prefecture, or local administration. No dead have been reported.

The prefecture said in a statement Tuesday evening that “the situation is under control,″ though the fire has not yet been extinguished. It described the fire as “particularly virulent.″

It came on a cloudless, windy day after a lengthy heat wave around Europe left the area parched and at heightened risk for wildfires. Several have broken out in southern France in recent days.

Light gray smoke gave the sky over Marseille’s old port a dusty aspect as water-dropping planes tried to extinguish the fire in the outskirts of the city, which has some 900,000 inhabitants.

Hundreds of homes were evacuated. The prefecture urged people in the affected areas to stay indoors and off the roads. With the fire approaching Marseille, the prefecture also advised residents in the north of the city to keep windows closed to prevent toxic smoke from entering their homes.

One distressed family watched the smoke over their neighborhood in the hills above the port city and showed AP how the roof of their neighbor's house had been damaged in the fire as they worried about their own.

Marseille airport announced that the runway had been closed at around midday. The prefecture said train traffic was halted, notably after a fire neared the tracks in L'Estaque, a picturesque neighborhood of Marseille.

As a safety measure, the city's Hospital Nord switched to generators “due to micro power cuts.”

“The aim is to secure the imaging sector. We are not worried as we have a high level of autonomy,” the University Hospitals of Marseille said, adding that because of the disrupted traffic it asked workers to remain at their posts until the next teams starts its shift.