The Red Squirrel: The Great Acrobat of the Iberian Forest
By Jose Luis Gallego, environmental communicator (@ecogallego)
Restless, lively, and very curious about engaging with humans, the red squirrel (Sciurus vulgaris) is a tree-dwelling rodent that is unmistakable in appearance. With its long, bushy tail, ear tufts, and large hindquarters, the red squirrel is easy to identify. We’re also talking about one of the most abundant and ubiquitous of all wild mammals, making it very likely that we’ll encounter a squirrel whenever we’re walking in a woodsy area, be it a mountain forest or a city park.
A red squirrel in a tree. Photograpy: Ana Mínguez
Spotting a red squirrel is easy—we just have to take a moment to scan the tree canopy, and chances are we’ll catch sight of one as it leaps from branch to branch. The squirrel is undoubtedly one of the great acrobats of the Iberian forest. Endowed with powerful muscles, the squirrel can leap through thin air, covering distances of more than a metre, while accomplishing all kinds of aerial somersaults. They have very well-developed and dexterous hands with long nails that offer an excellent grip in just about any situation. The chases that male squirrels engage in during the mating season are particularly spectacular.
Squirrels mainly eat green and mature pine cones, grains, seeds, hazelnuts, and other forest fruits. They have a habit of hiding food—which they either store in holes dug into the ground or in tree hollows—as reserves for times of scarcity. When in need, squirrels locate these “pantries” using their sense of smell. During the summer, they spend much of the day napping in their hideouts and, contrary to popular belief, they do not hibernate. They have two litters a year (in March and August), and females can give birth to as many as four kits per litter. The red squirrel measures around 20 to 25 cm in length, weighs approximately 250 gr, and the tail can be as long as the animal’s entire body.
Exclusively at home in woodlands and essentially a tree-dweller, the red squirrel has adapted to life in the forest, whether coniferous or broadleaved, better than any other mammal. It lives throughout the Iberian peninsula and includes various subspecies associated to specific areas of distribution which can largely be identified by the colour of their coat.
A red squirrel. Photograpy: Ana Mínguez
Red squirrels mainly survive on a diet of green and mature pine cones, grains, seeds, hazelnuts, walnuts (which they manage to crack with their powerful jaws and sharp teeth), and other forest fruit. As I said, they have an astonishing ability to hide food in holes that they dig in the ground, a squirrel “pantry” of sorts. When winter sets in, and snow and ice make survival a struggle in mountainous areas, squirrels will find their food stores by using their sense of smell. They discard the empty hazelnut shells, cracked walnuts, and chewed pine cones on the forest floor, making this one of the best clues if we’re on the lookout for squirrels.
Given their incredible agility, squirrels are a challenging prey for their main predators, including the pine or beech marten, genet, Eurasian eagle-owl, and other diurnal birds of prey. Even so, squirrels have developed a sophisticated system to escape their enemies and avoid an attack. In most cases, the predator will go for the bushy tail, which the squirrel displays extravagantly as a lure—only to release it when attacked, much like lizards do, leaving the surprised pine marten or tawny owl clinging to the tail while the squirrel scampers away. A few days later, a new tail will have grown in its place.
Squirrels spend most of their lives in the trees. They become active at dawn and are exclusively diurnal creatures. During the summer, they spend much of the day in their hideouts, which are often abandoned woodpecker nests, to avoid the heat.
A red squirrel on the ground. Photograpy: Ana Mínguez
The abundance or scarcity of food in the forest determines when the breeding period of our protagonist begins, usually between late January and mid-April. Squirrels build their nests—called dreys—with intertwined bundles of dry leaves, tucked between two branches. Gestation lasts approximately a month and a half, and after they’re born, kits stay in the nest from May to July, keepìng close to their parents until they reach sexual maturity.
Among the red squirrels’ main foes is the stray cat, which often hunts them in city parks and the woods around villages. However, in recent years, the greatest threat to this indigenous species is the presence of an invasive species, which competes with the red squirrel, driving it from its territories: the grey squirrel (Sciurus carolinensis).
This exotic species arrived in Europe from the United States, most likely as a stowaway on a ship or after escaping from a terrarium. The grey squirrel has adapted perfectly to our forest ecosystems, thereby altering their balance. Compared to the indigenous species, the grey squirrel is larger, has a more varied diet, and has two litters every year. In addition, it can transmit a disease that is fatal to red squirrels. Given these circumstances, populations of the European species are dwindling in many parts of the continent, such as the UK.
The problem is so severe that the International Union for the Conservation of Nature (IUCN) has included the grey squirrel on the list of the one hundred invasive species most harmful to the biodiversity of the planet. Some countries, including the UK, Ireland, Italy, France, Switzerland, and Germany, are implementing campaigns to control this biological invader and prevent its expansion. The situation is just as serious in Spain, where the red squirrel is showing increasing signs of being displaced by the growing numbers of its grey counterpart.