Valentine’s Day is coming. If music be the food of love and you are a mouse do you need to go to school?


Full Screen Image – Wood Mouse, Glen Convinth, Highland Scotland ©Nick Sidle

The achievements and abilities of mice have been greatly underestimated by people throughout the ages. Yet another entry on that list is that most people are completely unaware that mice are accomplished singers, although since they choose to perform using a frequency way above the sounds detectable to human hearing, perhaps this is not our fault, perhaps the mice wanted to keep it private. One reason could be that, in the best Mediterranean romantic tradition, one major use of song by mice is to win the heart of another mouse they have fallen for. Whether this includes performances under balconies or a mouse equivalent of balconies is not, as far as I know, yet recorded.

Once you have caught up with the choral skills of mice, there is then an immediate question, are they born with a repertoire of songs that they can use or do they have to learn them from other mice? How much they have to rehearse before another mouse wants to listen to them is a different issue on which, like the balconies, I am again not aware if there is any research. The same is true for the issue of if for mice, like people, there are some of us whose abilities in musical performance are such that the best way to show we care about someone else is to stay silent and fall back on the alternatives like red roses, chocolates and candle lit dinners. If there are mice who would be best advised to skip the singing, then I hope that in their society they have different ways to show they care as well.

To return to the main question of whether mice are born with their songs or have to go to school, the answer, like so much in the natural world, is not that simple or, to put it more simply, looks like a bit of both. Two studies have identified both paths as being active for mice who aspire to be the next sensation on the mouse music scene. One set of researchers at Northeastern Ohio Universities found evidence of substantial learning taking place:

Development of Social Vocalizations in Mice

whilst another based in Japan showed an innate ability in mice to know the songs since they found that sibling mice raised by different foster parents had the same repertoire of songs as their own biological parents and each other:

Cross Fostering Experiments Suggest That Mice Songs Are Innate

So, to make it in the music business as a mouse you need just the same as we do. You need instinct, innate ability and talent, a lot of hard work, possibly some help and even then probably still just a bit of luck. So I wish all mice and people with romance on their mind and a hint of love in the air all the luck they need on February 14th and let’s hope that everyone, and every mouse who wants to, finds the happiness and futures they seek together for however long it can last.


Gallery – Glen Convinth

Gallery – Scotland’s Mammals


Wood Mouse – Apodemus sylvaticus


Hair, Ice, Fungus – Which?


Full Screen Image – Hair Ice, Battan Forest, Glen Convinth, Highland Scotland ©Nick Sidle

The answer is actually all three. This rare phenomenon is called hair ice and is made up of tiny filaments of ice crystals formed on and exuding from dead wood when the conditions are right, it is the infrequent occurrence of the perfect conditions that means it is so rarely seen. It arises from the pores in the wood structure where the bark has been lost. What is required is a very cold temperature below freezing, for the dead wood to be saturated with water and very wet and for the right humidity in the surrounding air which must be high. After that, this particular type of frost can form as hairs about 0.01mm in diameter so it is no surprise that if you touch it, it melts. Now comes the fungal bit. For hair ice to form, what is also required is the presence of a fungus, Exidiopsis effusa, in the wood – an association reported by a team of scientists from Switzerland and Germany and reported in the journal Biogeosciences.

Evidence for biological shaping of hair ice

Hair ice was first recognised and studied in 1918 by Alfred Wegener, perhaps better known for his work on the slightly larger in scale question of tectonic plates. He suggested an association with fungus but it is only the recent work that has finally revealed what that is. In the absence of the fungus, ice forms on the surface of the wood as an encrusting layer, only if the fungus is present then the hairs form and, subject to the temperature staying below freezing, grow. The researchers hypothesis is that the hair ice structures are stabilised by a recrystallization inhibitor that comes from the Exidiopsis effusa. The team showed the presence of complex organic compounds, lignin and tannin, in the ice and identify these as the substances preventing the formation of larger ice crystals on the surface of the wood. Lignin and tannin are metabolic products of fungal activity and Exidiopsis effusa appears to have been the organism to provide all the right conditions.


Full Screen Image – Hair Ice ©Nick Sidle

For someone thinking as a scientist, this sort of discovery makes a beautiful natural phenomenon, even more a wonder of the forests. If for you complex organic compounds get in the way of appreciating a fleeting, unusual and exquisite event in the wild, then there is still the alternative name of ‘Snow Fairy’.


Gallery – Glen Convinth


Fungus – Exidiopsis effusa