In the midst of autumn, on the side of a busy bicycle and pedestrian path, you can still find some animals brave enough to survive in these pockets of urbanised wilderness.
Wood mice are some of our commonest mammals in the UK, and with their large ears and eyes, and long tail, they are easily recognisable. They are our commonest mouse species, and form an essential part of many predators' diets – in fact, Tawny Owls won’t breed if wood mice numbers are too low.
Typically nocturnal, wood mice will venture out in the day when searching for food, and this juvenile mouse is busy feasting on fallen blackberries, providing an important mechanism of seed dispersal for the blackberry bush, as well as sustaining itself. Often wood mice will cache food in underground burrows, where they come back to it later in winter months or when food is short.
Interestingly, wood mice tend to leave the flesh of fruit and eat only the pips. This juvenile mouse is carefully manipulating the blackberry, opening out the flesh and pulling out the small seeds, which the mouse loves.
This mouse’s small fingers grasp the blackberry tightly – but when the mouse is fully grown and sexually mature, the length of the phalange bones in her fingers will vary depending on whether she is male or female, an example of sexual dimorphism. This sexual dimorphism in digits has been recorded in many mammals, including humans, but was only relatively recently discovered to exist in wood mice.
Our juvenile mouse is not yet fully grown, as adults are typically between 8 to 10cm, with a tail of between 7 and 9cm! This mouse will continue to grow throughout the rest of autumn, before nesting communally with other mice underground. A group of mice is known as a mischief!
Although young, this wood mouse may actually breed before the end of the year if there is enough food around to supply her and her offspring with during winter, although litters in autumn and winter are normally a lot smaller than those born in spring and summer.
After her feast of blackberries, our wood mouse cleans herself, before returning to the undergrowth by the side of the pavement, hidden from the urban world once more.
References and Further Reading
Leoni B, Canova L, Saino N. (2005) “Sexual dimorphism in metapodial and phalanges length ratios in the wood mouse”, The Anatomical Record: Volume 286A, Issue 2, pp. 995-961
Sunyer P, Munoz A, Bonal R, Espelta J. M. (2013) “The ecology of seed dispersal by small rodents: a role for predator and conspecific scents”, Functional Ecology: Volume 27, Issue 6
The Mammal Society (2020) Species – Wood Mouse, Available: https://www.mammal.org.uk/species-hub/full-species-hub/discover-mammals/species-wood-mouse/ [Accessed: 17/10/20]
The Wildlife Trusts (2020)1 Wood Mouse, Available: https://www.wildlifetrusts.org/wildlife-explorer/mammals/wood-mouse [Accessed: 17/10/20]