10 Bizarre Facts About Mice (That Aren’t Cheesy)
For most people, their opinion of mice goes no further than viewing these rodents as pests or as pets. But these furry critters lead a strange existence that few are aware of. From an island where the common house mouse evolved into something terrifying to mice that regrow body parts, here are 10 fascinating reasons why you’ll never look at mice the same way again.
Related: Top 10 animals with amazing regeneration powers
10 Japan’s unique rodent outbreaks
Japan is known for its remarkable architecture, traditions and homegrown crafts. But the country still has a unique claim to fame. Every 120 years a rare event called masting occurs. This is when the dwarf bamboo (Sasa Borealis) blooms, reseeds and dies on a large scale.
Legend has it that masting is also the cause of the widespread rodent outbreaks that occur around the same time. But it wasn’t until 2022 that researchers at Nagoya University in Japan confirmed that the legend was indeed fact. It turns out that the bamboo is a boon to Japanese voles, providing them with ideal breeding conditions and tons of seeds for food.
Remarkably, the study also found that the positive effects of masts on mouse populations persist for up to two years after the event, even though the bamboo is long gone. However, this is not a great time for agriculture and forests, as widespread plant damage and tree death have also been linked to these rodent outbreaks.[1]
9 Unknown semi-aquatic mice
About a century ago, a mouse was caught in a stream in Ethiopia. Long, wide legs and waterproof fur showed that it was adapted to life in water. It was the only specimen of its kind, Nilopegamysfound, and it is now considered extinct.
Other mice, however, splashed around in rivers in West Africa and the Congo Basin. For many years this species was studied, but only recently did researchers confirm some facts.
Indeed, they were semi-aquatic mice that also had waterproof fur and long, kangaroo-like legs to better navigate their wet environment. However, it was not one but two species that were new to science: Colomys lumumbai And Colomys gosling.
DNA tests also confirmed they were linked Nilopegamys, the specimen captured in Ethiopia. This makes the two living water voles the rarest animals in the world.[2]
8 The mysterious mountain mice
The Andes Mountains in Patagonia hold a mystery. The area is home to Abrothrix hirta, an adorable mouse known for his soft, shaggy hair. But even though they belong to the same species, these mice have different sizes, and researchers aren’t sure why.
Even more bizarre is that how big or small they are depends on where in the mountains they live, with the eastern population becoming larger than their eastern side relatives.
So, what influences the same species to grow larger or smaller? It could be something called the rain shadow effect. This is when clouds are forced higher as they pass over mountains, a phenomenon that causes rain on the first side of the mountain that the clouds hit. In this region, the rain shadow effect causes more showers on the western slopes of the mountain.
More rain means more food. Adequate nutrition ensures better nourished mice and larger specimens. That’s the theory anyway, and scientists admit they don’t fully understand how this process might work.[3]
7 The mouse that cleaned a house
Actually it was more of a barn. It all started a few years ago when Stephen McKears noticed someone was cleaning out his workbench in the shed every evening. More specifically, small metal objects he took out of a box mysteriously returned to the same container.
To catch the nighttime cleaner, the senior from Gloucestershire installed a night camera. He wasn’t quite prepared for what he captured. One night a mouse climbed out of the box. The rodent then proceeded to pick up and carry nail clippers, screws and a metal chain, depositing each item back into the box.
At first glance, it may seem strange that a mouse is obsessed with metal parts. But these rodents have strong instincts for organizing their environment, hoarding and even cleaning around them, so it’s likely that one or more of these urges drove this mouse to go after the man.[4]
6 Some mice recognize themselves
Researchers use the ‘mirror test’ to determine whether a specific animal can demonstrate a higher degree of thinking by recognizing itself in a mirror. The method is simple. First, a mark is placed on an animal’s forehead. If the creature looks at a mirror, sees its reflection and the mark, and then touches its own forehead (not the mirror version), this proves that the animal is aware that it is looking at itself in the mirror.
Only a few animals have passed this intelligence test, including some primates, elephants and dolphins. The latter could not touch their foreheads, but as soon as researchers marked their heads, they ran to an underwater mirror to look at themselves and examine the mark.
In 2023, researchers reported that mice appear to have passed the coveted mirror test. After applying white ink to the foreheads of black mice, the rodents spend more time sitting in front of the mirror and grooming their heads, presumably to get rid of the ink. Interestingly, the mice only showed this behavior when they were used to mirrors or socialized with other mice that looked like them, and the inkblot was large.[5]
5 Mice living in mammal hell
High in the Andes Mountains lies a place called Puna de Atacama. It is so hostile and desolate, with hardly any oxygen or water, that NASA has used the plateau to simulate conditions on Mars. In the 1970s and 1980s, scientists found the mummified bodies of leaf-eared mice (Phyllotis vaccarum), which only reinforced their suspicions that Puna de Atacama was a dead zone for mammals.
They suspected that the rodents had been accidentally or deliberately brought to the area by Incas, who often went up the mountain to make sacrifices. Once there, the animals could not survive and perished. But when scientists recently revisited the arid landscape, a different story emerged – especially as they started capturing live leaf-eared mice.
Apart from discovering healthy rodents at a height, no mammal had been found alive, but other evidence supported the idea that the mice had been living in the mountains for a long time and raised their families in the mountains and never hitched a ride with the Incas. Some mummified mice were close relatives, and there were also mouse holes. However, it is still unclear how they survive and why they prefer to live there.[6]
4 House mice with a horrible taste
Mus musculus is a common house mouse around the world. To the homeowners’ dismay, they nibble on everything in the pantry. But for researchers on Gough Island, in the South Atlantic Ocean, their experience with this rodent veered sharply left into the realm of horror.
The mice on this island are huge. A normal house mouse weighs 19 grams. But on Gough the rodents are often twice as big and can weigh as much as 51 grams, making them the heaviest and largest mice in existence. And they’re not just fat. Their bone structure is larger than that of house mice living elsewhere.
One reason these mice are so large could be that they have no predators or competition for food. And their favorite food is stomach-turning.
The rodents have developed a taste for baby seabirds and often eat them alive in their nests. Researchers have noticed that this gruesome behavior not only increases the size of the mice, but also drives some bird species to extinction.[7]
3 Melodic mice
In the cloud forests of Central America lives a rodent called Alston’s singing mouse. This is not a whimsical name. They really sing. When romance is in the air, men will woo women through squeaky tunes, often in tones inaudible to humans.
But what caught researchers’ attention are the audible “conversational” songs that occur between male mice. The chatter is rapid and strangely polite. While one mouse ‘sings’, the other remains silent. As soon as the singer becomes silent, his companion responds almost immediately with his own song. These back-and-forth musicals showed that the mice can communicate using almost 100 different notes.[8]
2 This mouse turns poison into painkillers
The bark scorpion is the most venomous scorpion in North America. The sting is incredibly painful and children and vulnerable adults can develop seizure symptoms and paralysis. They even risk death. Even healthy adults can develop breathing problems. Compared to how humans are affected, small mice should die shortly after the sting.
However, when the grasshopper mouse is stung, it does not decay. At just 4 inches long, the rodent’s response to the injection of the deadly poison is unusually blasé. It may jump away first and then take care of itself or turn the scorpion into a hearty meal.
The mouse is not only immune to the bark scorpion; they experience the poison as a painkiller. Once the poison is in their bodies, certain proteins attach to the poison molecules, preventing them from causing physical pain. This response numbs the mouse’s entire pain transmission system, temporarily preventing them from feeling pain, not just the pain associated with the scorpion sting and venom.[9]
1 Mice growing new tails
Some amphibians, such as salamanders and salamanders, are not bothered by losing a limb or tail. They just let them grow again. The ability to regenerate body parts isn’t something you’d associate with mammals, but that doesn’t stop the African spiny mouse from exhibiting similar healing powers.
This little miracle not only regrows tails, but it can also seal tears in ears and generate new skin, nerves, muscles, and even toe tips, all without leaving scars. To achieve this feat, the mice rely on immature cells similar to those found in salamanders and salamanders. These cells can turn into different tissues as needed, repairing missing skin, toes, or wherever the wound is located.[10]