The wolf (Canis lupus) is the largest representative of the Canidae family. Its muzzle is pointed, eyes slanting and its ears relatively large and upright. The coat is yellowish-brown with a grey hue, in winter predominantly grey. Unlike dogs, it has a 10 cm long and 2 cm wide black stripe on the forearm. The dog and the wolf crossbreed successfully. Some large breeds of dogs may look very similar to wolves, but dogs never have such strong molars.
Wolves live in packs with a strictly defined hierarchy. The minimum territory required by an individual wolf to survive is said to be 25 km2. Seasonal prevalence depends on prey migration. If possible, wolves move through easily transitional territory, which is why in Slovenia their tracks are common on forest (truck or tractor) trails. When searching for food, they can travel 40–70 km at once and it is known that they can walk the distance of 160 km in one night. The wolf is a predator of large ungulates, which it exhausts during the long chase. With such hunting, it catches especially the animals in poor physical condition. That is why the wolf is an extremely important selector of large ungulates. In Slovenia, the wolf mainly preys on deer, also feeds on carrion, and occasionally attacks all sorts of domestic animals (dogs, horses, cattle, sheep and goats). Mating takes place from December to March. The female wolf is pregnant for 62–64 days and the puppies are whelped in the den. In Slovenia, most wolves are whelped in April. The litter usually consists of 5–8 puppies that are blind at birth and have short, dark hair. The puppies start leaving the den after eight weeks and they reach sexual maturity at 22 months. The population is dominated by males. 40–50% of wolves perish within the first year of their life. Their lifespan is 12–16 years. They have virtually no natural enemies, while there are known cases of cannibalism. The wolf can also become infected with rabies. It is not dangerous to man.
In Slovenia, wolves are most commonly found in beech and fir forests, which cover extensive mountainous areas of the Dinaric Karst. The wolf is now more or less exterminated in Europe and is only found in remote areas.
The bear (Ursus arctos) is the largest representative of the Carnivora. Its body is strong and stout. It uses the entire sole when walking. The eyes are small, the ears short and rounded and the tail also short and hidden in the fur. The colour is generally brown but quite variable. Males are larger and stronger than females. The heaviest hunted males weighed more than 300 kg.
The bear is primarily a nocturnal animal, although we often see it during the daytime as well. It moves in gait or canter. Although seemingly clumsy and slow, it can run very fast. It is a good swimmer, while younger (and lighter) animals also climb well. Its eyesight is weak, while its hearing and smell are well developed. It rests in underground cavities, plenty of which can be found in our Dinaric Karst. The bear is not very picky about the den. Sometimes a shelter under a fallen tree or a dense stand of young trees is sufficient. It sleeps through the winter, but this is not a true winter sleep (hibernation). The bear often leaves the den during the winter. It is omnivorous: it feeds on fungi, forest fruits, subterranean parts of plants and their green parts, invertebrates, rodents and carrion. It can only catch adult ungulates in high snow. It also occasionally preys on domestic animals. The bears mate from April to June. During this time, the female bear is in season 2 to 3 times. Its pregnancy lasts 7–9 months. It usually whelps every other year. In the winter (December–February), one to four cubs are whelped, usually in the den. Because the bear whelps during the “winter sleep” when it does not feed, the cubs are surprisingly small at birth, weighing around 700 g. They reach sexual maturity between the ages of 2.5 and 4 years, with a life expectancy of 30–40 years. In Slovenia, the bear has almost no natural enemies.
The bear inhabits deciduous, coniferous and mixed forests in lowlands and mountains. In Slovenia, it most commonly lives in the beech-fir forests of the Dinaric highland Karst. The choice of habitat is highly influenced by humans. In Slovenia, the best conditions are found at an altitude of 400–1200 m.
The lynx (Lynx lynx) is a representative of the Felidae family. It has a short and wide head, tufted ears, tall legs and a short tail. The reddish-grey back is strewn with brown freckles. The end of the tail is black and the belly whitish. On the cheeks, the hair is extended into a “beard”. In Slovenia, the lynx male weighs 18 to 25 kg on average, while the female weighs slightly less.
Except during the mating period, it is solitary. Its habitat is 10–60,000 ha. The lynx is a highly specialized predator that hunts from ambush. When hunting, it relies on sight and hearing. In the area of Kočevsko, its prey includes deer, fallow deer, wild boar, chamois, badger, rabbit, wildcat and of the domestic animals dog, cat and sheep. Mating starts in February or March. After 70–74 days of pregnancy, the female lynx whelps 2–3 cubs. The lynx’s lifespan is 14–17 years. It has no natural enemies but retreats to the wolf.
It inhabits extensive lowland and mountain forests with an abundance of old as well as fallen trees. In Slovenia, it lives especially in the area of the Dinaric beech and fir forest. The lynx was re-settled in Slovenia in 1973 when three lynx couples caught in Slovakia were released in Kočevski rog. In 2019, there were new animal settlements, as the lynx population in Slovenia dropped significantly for a variety of reasons.
The jackal (Canis aureus) is a representative of the Canidae family. It is as large as a medium-sized dog. From its snout to the tip of its tail, we measure between 120 and 125 centimetres. Its body weight ranges from 10 to 13 kilograms, in males up to 15 kilograms. The colour of the coat is not uniform, as it comes in reddish, black, gold brown and silver shades. It walks on its toes so an imprint of the paw pads is well visible on a soft surface. A characteristic of the jackal, which also distinguishes it from other Carnivora, is that its pads are grown together between the 3rd and 4th fingers. The footprint is thus in the shape of a heart. The paw itself, which leaves the footprint, is around 5–6 centimetres long and 3–4 centimetres wide.
The diet of jackals is highly dependent on the supply in nature. The species is opportunistic and not very picky about food. It feeds mainly on rodents, small mammals, invertebrates, amphibians, reptiles, birds and also carrion. It also eats a variety of fruits and seeds. In Serbia, research has shown that it mainly feeds on slaughterhouse waste. With their diet, jackals perform an important task as they prey on the pests of agricultural areas and remove the dumped slaughterhouse waste near human habitats.
Jackals live in packs led by a dominant male and a dominant female that mate with each other. The pack also consists of their cubs and possibly the cubs from the previous litter. The couple are loyal until the death of one of them. The possibility of insemination of the female is 6–8 days a year. Mating in Europe takes place between January and March. After insemination, the female is pregnant for about 63 days. The female whelps from 2 to 10 blind cubs in the den and nurses them for 8–10 weeks. When the cubs are 3 weeks old, they leave the den for the first time and start exploring the surrounding area. The cubs reach sexual maturity at 11 months. They can then leave their parents or stay for another year and help raise the next generation. The survival of the new generation is greater in the pack, where other animals help raising the young.
The fox (Vulpes vulpes) is a member of the Canidae family and inhabits forests, arable land and suburban environments. It is best suited to a mosaic intertwinement of small forests and open terrain. The fox is increasingly adjusting to life near cities. It has a slender body on relatively short legs. The tail is very long. Its back is usually reddish-brown and the belly off-white. Grey hues are more pronounced in the winter hair. The back of the ears is always black and the tip of the tail is white. Males are larger than females. An adult male fox weighs up to 10 kg.
The fox is primarily a nocturnal animal, however, especially in autumn and winter, it can also be seen during the daytime. It rests in a lair, which it digs itself, or occupies an abandoned badger’s sett. Although the fox has short legs, it runs swiftly and makes long (3–4 m) jumps. It is a pretty good swimmer and can also climb less steep trunks. Its habitat ranges from 2.5 to 15 km2. The fox is an opportunist and an omnivore in its diet. Its food mostly consists of rodents (up to 90%), but it also hunts rabbits, birds, fish, frogs, crustaceans, snails, insects and their larvae and eats carrion and fruits. It mates from January to March and the pregnancy lasts 52–53 days. There are usually 4–7 cubs in the litter that are without hair and blind, weighing 60–150 g at birth. The cubs start leaving the lair when they are 4–5 weeks old and by the age of five months, they are already independent. The lifespan of foxes is up to twelve years. Males are more numerous in the population. Fox’s natural enemies are the wolf, the lynx and the golden eagle, while the goshawk and the Eurasian eagle-owl are also a threat to the cubs. The fox is the main carrier of rabies. It can also infect other mammals and humans with this deadly viral disease. In Slovenia, the vaccination of foxes against rabies is carried out by airplanes dropping baits into the forests.
The beautiful demoiselle (Calopteryx virgo) is a dragonfly inhabiting clean, oxygen-rich watercourses with denser waterside vegetation that provides more shade. The typical habitat of this species are natural forest streams (Kobilji curek), where they fly from May to late September. In Slovenian, it is named after the dark blue metallic colour of the wings that glitter in the sun. Its body is nearly 5 cm long and its wingspan measures 6 cm.
The male courts the female – which is a rarity for dragonflies – by dancing and showing off its beautiful colours. It persistently drives away competitors and defends its territory. After mating, the female lays the eggs on the waterside parts of the plants. The larvae hatch from them, which live about a year in the stream and do not resemble the adult animals in the slightest. They are predators and eat other aquatic larvae, tadpoles, as well as small fish. After moulting for a couple of times, the larvae crawl from the water to the waterside vegetation and transform into an adult dragonfly. The latter only live for about a month and they hunt insects in flight, such as mosquitoes and midges.
The Eurasian wren is one of the smallest Slovenian birds, measuring only 10 cm from its beak to its tail. It weighs about 10 g, which is as much as two bags of sugar that comes with coffee. It can be recognized by its highly raised tail. Due to the different shades of brown over its body, it is quite unnoticeable. It has stripes along the wings, the line above its eyes is light brownish-white and the brown stripe also continues over the eyes. The beak, which is brown in colour, is short, thin and slightly bent. The legs are brown and of medium length. It can be observed all year long since it does not leave us in the winter. When it is cold, several Eurasian wrens squeeze together in the holes to keep warm and lose less heat than if they were fighting the cold individually.
These birds prefer to live by the streams (as in the valley of Kobilji curek), sneaking between the roots in moist forests and utilizing the shelter provided by hedges in settlements. In the spring, the male makes several round nests between the roots of waterside trees from mosses, lichens and grass. The female then chooses one for laying the eggs. One male can also have several females at once. They only nest once a year.
Despite its small size, the Eurasian wren is a good singer with an extremely strong voice. Its proximity is usually detected only by its typical calls and loud singing. It sings with repeated tick-tick or clink when in danger, while normally and during mating, it chirps surprisingly loudly.
The bats from the genus Plecotus have distinctively long ears, but when they are resting, they fold them under their wings. They feed mainly on nocturnal butterflies, flies, small turtles, but also caterpillars and spiders that they catch directly from twigs and leaves.
Their typical habitat is deciduous mixed forests. Long-eared bats mostly do not migrate; nevertheless, the furthest recorded migrations are those between summer and winter shelters, several tens of kilometres away. Summer maternity colonies are mostly formed in tree trunks or attics of churches and buildings, while caves, cellars and tunnels most often serve as winter shelters.
The Ural owl resides in mixed forests of mountain areas. Although owls of darker shades exist, this large owl’s feather adapts to the environment, becoming lighter due to the presence of snow. It was named the Ural owl because its tail is longer than the tail of other owl species. The fringed edges and huge surface of their wings allow for slow swinging, making the flight almost inaudible, and these owls a top predator that feeds on rodents and smaller birds. Bones, hair and other undigested remains are thrown out in the form of mucus.
The dormouse is a real sleepyhead! It spends more than six months in winter sleep, much longer than other mammals. When it finally wakes up in the spring, it first checks the buds such as beech or acorn, which will later produce fruits, for them the most delicious food. If there are not enough buds, they will return to their hiding place and continue to sleep until the next spring. The Romans hunted and prepared dormice in various ways, considering it a real delicacy.
As early as in 1689, Janez Vajkard Valvasor wrote about the dragon offspring that he spotted in the bursting spring of Lintvern (near Vrhnika). He did not know what sort of animals these were and he described them as: “Probably a sort of lizard or an underground worm that can be found elsewhere as well.” Even then, he was aware that under the Earth’s surface there was something highly mysterious and hidden – the underground cave world. About a hundred years later, there was a battle for its description and prestige, in which Joseph Nicolai Laurenti won over Giovanni Antonio Scopolio. Thus, the human fish acquired its Latin name and became the first cave animal in the world to be scientifically described. Scopoli later correctly classified it among amphibians and not among fish, as the Slovenian name could mislead him. In 1801, it was presented to the scientists of that time in London and became world famous. Researchers were able to find the animals in the caves in the Dinaric Karst in Slovenia, Italy, Croatia, Bosnia and Herzegovina and Montenegro. The specimens were being sent from Slovenia all over the world; they were even experimentally inhabited in two European caves, where they supposedly live even today.
The story of the cave beetle Leptodirus hochenwartii is a bit younger but no less interesting. In 1831, a cave guide, Luka Čeč, discovered it in the Postojna Cave. He took it to Count Hochenwart, who showed it to Ferdinand Schmidt, an amateur entomologist who lived in Ljubljana and studied insects because he missed having his own garden. He described the beetle, gave it a Latin and a Slovenian name – “drobnovratnik”. This was the first described cave insect in the world. Since this animal was missing a part of the body, Schmidt offered the prize to the one who brought him a whole beetle. 16 long years after that, he found it himself. During his search, he discovered and described a wide array of other cave animals, showing the scientists an entirely new world below us. The Postojna Cave thus became the cradle of world speleobiology, that is, the biology of cave animals.
Did you know that not all bears go into their dens in the winter? It all depends on the food supply in the autumn (when the bear accumulates fat) and in the winter (when there is markedly less food). If a bear is accustomed to food sources close to humans (composts, garbage cans, wild landfills, meat from the slaughter), it will not go into hibernation but will be visiting a village.
Did you know that the roots of a tree extend beyond its treetop? In the forest, the roots of the trees touch and intertwine, protecting the forest ground from slipping and erosion.
Did you know that bark beetles are polygamists? The male hollows out a cubbyhole in the spruce tree and invites the females into it. Usually, 2 or 3 respond. After fertilisation, they each dig their own tunnel away from the cubbyhole and lay eggs in the walls of the tunnel.
Did you know that not all flowers have colourful blossoms? Along the Ajdovski zid wall, in the Kobilji curek stream and in Lanišče, we may observe a flowering henbane bell in April, which has black-purple, brown blossoms. The plant is poisonous.
Did you know that newts and fire-bellied toads have warning colours only on their bellies? In case of danger, a fire-bellied toad throws itself on the back, arches its garish belly and plays dead. Predators think the animal is dead and bloated, thus inedible.
NEWTS AND FIRE-BELLIED TOADS
Did you know that unroofed caves are created because their ceilings become thinner and then collapse? One day this will happen to the Postojna Cave and it will look like a cave by the Roman wall in Vrhnika.