Wild boar habits, behavior, and reproduction

Morphology and Identification of Wild Boars

The wild boar is an ancestor of the domestic pig and is similar in build to the domestic pig, with a stocky body, short neck, thin legs, and a short tail ending in a tuft of black hair. It is covered with characteristic stiff hairs (called "setae"), which are usually dirty brown; some individuals are almost black in color, while older individuals are distinctly gray.

Youngsters are called "rayones" because their fur is yellow-brown with 11 lighter stripes running lengthwise (5 on each side and 1 on the back); this color begins to disappear at three to four months of age.

Males are significantly larger than females; in addition, the latter have a pointed snout and smaller canines, while males have a broader and larger head, and canines (called "fangs", "defenses" or "blades") are relatively large and curved upwards.

The size of wild boars decreases in the west and south of Eurasia; thus, in the USSR, specimens weighing more than 300 kg have been reported, in Poland - more than 200 kg, while in France they rarely exceed 150 kg, and in Spain - males weighing more than 120 kg are rare. In the province of Burgos, the average head-body length of males and females was 139 cm and 126 cm respectively, with tail lengths of 20 cm and 18 cm; the average weight of 28 males and 22 females over three years old was 88 kg and 62 kg respectively, with the largest of 197 weighing 128 kg. However, in Doñana (Huelva), the average weight of males and females was 54 kg and 44 kg respectively. The maximum weights were 80 kg and 63 kg respectively.

Wild boar tracks:

Wild boars often leave a large number of clear tracks to indicate their presence. These tracks are very characteristic: they mark the two main hooves, and the two secondary hooves behind, which are almost always clearly marked. Other ungulates, especially deer, occasionally leave their hind hoof tracks on very soft ground, but never as clearly as wild boars. The distance between two consecutive marks of the same foot is 30-40 cm (50-60 cm for deer). The droppings are black, shiny when fresh, shaped like blood sausage, 4-5 cm in diameter, and consist of numerous round and flat elements (like small chestnuts) that decompose when dry. The wild boars roll in the mud, making "banias" burrows, which measure 1.5 x 0.7 m (sometimes larger), very distinctive and conspicuous, and their tracks occur in large numbers; next to the bathtub there is usually a large tree, on which they rub their bodies, so that the trunk appears bare, covered with mud, and with bristles clinging to it. The wild boars rummage through the grass, leaving numerous furrows in their path, which are often the most obvious sign of their presence. animals-do-badgers-eat.html">Badgers sometimes leave similar tracks, although these are usually smaller and deeper.

 

"Beds" are dug oval sites, sometimes filled with herbs and vegetation gathered from the surrounding area; they are usually grown in impenetrable thickets and face south. They are very similar to bear beds and can be distinguished by the characteristic hairs.

Feeding of Wild Boars

Wild boars are true omnivores and probably have one of the widest diets of any animal. A brief list of the food of the Spanish wild boar includes acorns (by far the most common), beech nuts, chestnuts, potatoes, chestnuts, beetroot, wheat, barley, corn, apples, pine nuts, olives, grass, mushrooms, worms, insects, scorpions, frogs, toads, fish remains, lizards, snakes, eggs and chicks of various birds, adult birds, young rabbits, rodents, moles, deer and fallow venison, etc. In general, it can be said that their diet is much richer in plants than animals, and they tend to specialize in one food each night. Most of their food is located underground and is obtained by searching for food with their noses, thanks to their highly developed sense of smell. Two studies carried out in Doñana have yielded very similar results. According to them, the bulbs of the snail (Scirpus maritimus) provide 60% of the annual diet; second place is other bulbs, tubers, root plants and grasses - codfish (Cynodon dactylon). Among the animals eaten, one amphibian stands out, the Gallipato rabbit (Pleurodeles waltl), but animals of all groups appear, including rabbits and carrion of ungulates. In the southwestern Pyrenees, the analysis of 239 stomachs in autumn and winter showed that their diet was almost vegetarian, mainly based on beech nuts, oak and holm oak acorns, hawthorn, rose hips, etc.; animal food was scarce and mainly composed of invertebrates.

Behavior of wild boars

Data on habitat use by wild boars in Spain are scarce. The social unit is a matrilineal group composed of one or more females and their offspring. This group is called a herd, and its members share a common foraging area, which always includes dense bushes for sleeping during the day, a few swamps and areas with abundant food. In a mark-recapture study in France, 90% of the animals were killed within 5 km of the marking site, indicating that they have a distinctly sedentary lifestyle (home ranges of up to 60 km2 have been measured in this country over the course of a year). They can share this area with other herds, although they generally avoid being in the same area at the same time. When this happens, they may ignore each other or attack each other. Males are solitary and have large home ranges covering multiple herds. They lead less stable lives than social animals. In France, one male rhino that was radio-tracked for a year had a home range of 150 km2. Some individuals are known to travel long distances. A young female rhino tagged in France traveled 50 km in a straight line in just over three weeks, but never traveled more than 7 km on each leg. A male elephant is known to have died 250 km from where it was tagged, less than a month later.

The size of the area covered each night also depends on the concentration of food and the distance between the feeding area and the sleeping area. Three males of the same age lived on 45, 70 and 112 hectares of land respectively, and travelled distances between 2 and 15 kilometres.

In most of Spain, wild boars are nocturnal. However, in areas where they are not persecuted, although they still show a clear tendency to crepuscular and nocturnal activity, they can also be observed during the day, as is the case in the Doñana National Park. It turns out that in France, people spend an average of fourteen hours a day in bed. In Doñana, the researchers studied the percentage of time they spent on each activity: on average, they spent 59% of their time eating, 27% moving, 8% grooming, 4% surveillance, 2% sexual interactions, and a very small percentage (0.1%) in aggressive interactions with other wild boars.

Time spent eating varied between sexes and age groups: females spent significantly more time eating (60% to 67%) than young males (50%) and adult males (29%); however, they spent more time commuting. These differences can be explained by the reproductive system: since males only interact with females during mating and do not participate in reproduction, their reproductive success depends on his ability to contact and fertilize females, and therefore on the time he spends on movement, marking and surveillance. Conversely, the reproductive success of females increases as their ability to eat improves. The young are the ones who spend the most time playing aggressive games, which mark the beginning of the hierarchy. The social unit is the matrilineal group or herd, consisting of one or more females and their offspring, sometimes the result of consecutive births. Adult males are usually solitary, although they are sometimes accompanied by subadult males, who are referred to as "squires" in hunting literature. The composition of the herd changes continuously throughout the year due to rutting, birthing, and hunting. During the rutting period, young males (8-9 months old) are expelled from the matrilineal group by adult males; they form unstable and erratic groups until they begin their ultimately solitary lives. During the birthing period, females isolate themselves until two or three weeks later when they rebuild the herd. Ultimately, hunting introduces unpredictable changes to the herd. In a study conducted in Doñana, based on the observation of more than seven hundred wild boars, 39% were solitary adults, 32% were in matrilineal groups, 13% were subadults (alone or in groups), 9% were in association with subadults and 7% were in association with adults (almost always a male with a female). Large herds are formed by the gathering of several females and their offspring. The average number of scratches when chasing a female animal is close to five. The largest herd consists of sixteen animals.

The density of wild boars is much higher than that of other ungulates of similar size, such as roe deer or red deer. In favorable areas of the province of Burgos, the average density is 4 wild boars per square kilometer; in the Riaño National Hunting Reserve (León), it is 2.84 per square kilometer. In the province of Burgos, mortality in the first months after birth is estimated at 17%. For individuals over six months of age, life expectancy is only twenty-seven months. Mortality in the first two years is 81%; however, survival rates are much higher beyond this age. In the hunted population of the Monfraguí Natural Park (Cáceres), the average age of males and females killed was 21.9 and 24.9 months, respectively; 71% of males and 64% of females were under two years of age. The oldest males and females were 7.2 and 8.5 years old, respectively. The lifespan of this species in the wild is nine to ten years, although they can reach twelve or thirteen years. These figures are very similar to those of other European populations that are subject to severe hunting pressure, which is by far the main cause of mortality. In Burgos, two male elephants, aged three and five, became seriously ill due to infections in wounds received during mating. Another 2-year-old male elephant had severe injuries to his groin and hip, presumably caused by wolves, which are likely the only natural predators of adult elephants.

Population parameters for wild boars fit the r-strategy, with high reproductive rates (enabling them to withstand severe hunting pressure) and strong colonization abilities. When wild boars expanded into what was then Old Castile in the late 1960s, the rate of expansion into new territory was estimated at about 24 km per year.

Reproduction in wild boars

In a study conducted in Burgos, the elephant rutting season occurs between October and January, peaking in November, and can be preceded by intense fighting between males, each guarding one or more females from a herd.

Gestation lasts about four months; babies are born between January and April (most - 60% - are born in March).If conditions are favorable, the second litter may be born in the autumn. This is rare in Burgos, but in Doñana, 10% to 20% of the herds observed in November and December have scratches. The litter size is related to the weight of the mother, which in turn depends on the age of the female and the food supply of the year. In France, females weighing 30-40 kg give birth to an average of 2.5 litters; those weighing 40-50 kg give birth to 4.25 litters; those weighing 50-60 kg give birth to 5.4-5.6 litters. In years with good food harvests, one more litter is born on average than in normal years. Since the weight of wild boars decreases with altitude, the average litter size follows the same trend; thus, in Austria, the average female carries 5.8 litters, in France 4.8, in the Spanish Pyrenees 3.3, in Burgos 4.3, and in Monfragué (Cáceres) 4.2. The percentage of pregnant females also depends on their weight and, therefore, on their age: thus, in Burgos, the pregnancy rate is 33% for females under one year old, 83% for those between one and two years old and 91% for those over two years old, figures that correspond to the results of other European studies, where these percentages also increase in years of abundant food supply.

Wild boars produce milk only from the teats of their young, and each striped boar always suckles from the same teat. The front teats secrete more milk, so the rays that eat them grow faster and are less vulnerable to predators or food shortages.

animal tags： wild boar