Conservation and management of wolves in Croatia

biology of wolves

Scientific classification

Spread, condition and number of wolves in the world

Outer appearance, physical features

Wolf's way of life

Reproduction of wolves

Wolf's habitat and diet


Scientific classification

		The grey wolf (Canis lupus) is a mammal of the order Carnivora and the dog family Canidae. Besides the grey wolf there are two more free-living types of wolf known - the red wolf (C. rufus) and the Abyssinian wolf (C. simensis). The red wolf used to inhabit the southeast part of the USA, but his natural populations were most likely exterminated by the 1980s. The Abyssinian wolf considered the jackal until recently, numbers about 550 specimens at the moment, mostly inhabiting the Bale National Park in the mountainous regions of the Southeast Ethiopia (Route and Aylsworth, 1999).


	All dog breeds were created by domesticating wolves, in a process that started some 100,000 years ago, although some mixing with the wolf was recorded occasionally too (Vila and assoc., 1997) So nowadays the dog (C. lupus familiaris) and the wolf are considered to be the same species. The genus Canis includes also the coyote and two types of jackal who can all be crossbred. back to the top

Spread, condition and number of wolves in the world

The grey wolf historically inhabited each habitat of the Northern Hemisphere (from about 20°of northern geographical latitude up to the Pole) in which large even-toed mammals were to be found (Mech, 1995). The grey wolf belongs to the ecological niche of predators to large mammals of the Earth's Northern Hemisphere.
Besides the wolf this niche comprises also the mountain lion (Felis concolor) of the North America and the tiger (Panthera tigris) and the leopard (Panthera pardus) of Asia, but the wolf is the most valuable predator owing to his high density of population and considerably wider spread (Mech, 1970).

According to the data collected by Route and Aylsworth (1999) the grey wolf number in the world is currently estimated at some 150,000. This number of wolves lives in populations spreading through 41 countries worldwide in which the data on their number, population trends and the legal status were available (Table 1).

Table 1:
The grey wolf number, population trend and legal status in the world in 1999 (Route and Aylsworth, 1999).
For countries not listed there are no data available.

COUNTRY	NO. OF WOLVES	TREND	LEGAL STATUS
Albania	250	upward	unknown
Belarus	2000 - 2500	upward or stable	unprotected
Bosnia&Herzegovina	800	upward or stable	unprotected
Bangladesh	< 10	-	-
Bulgaria	800 - 1000	upward	some protected areas
Canada	55 000 - 65 000	stable, but varying	hunted, protected
Croatia*	100 - 150	stable, upward	protected
Czech Republic	< 20	upward	protected
Denamrk (Greenland)	50 - 75	likely downward	protected
Estonia	< 500	downward or stable	unknown
Finland	150	upward or stable	unknown
France	30 - 40	upward	protected
Germany	5 - 10	upward	protected
Greece	200 - 300	downward	unknown
Netherlands	0	exterminated	unknown
Hungary	< 50	stable	protected
India	1200 - 1500	downward	protected
Israel	150	stable	protected
Italy	400 - 450	upward	protected
Yugoslavia	500	unknown	unknown
Lithuania	900	stable	unprotected
Latvia	600	upward	unknown
Macedonia	> 1000	upward or stable	unprotected
Mexico	0	exterminated	endangered
Mongolia	30 000	stable	unprotected
Norway	5 - 10	upward or stable	protected
China	6000	stable	protected
Poland	1000 - 1100	upward	hunted, protected
Portugal	250 - 300	stable	protected
Romania	2500	stable or upward	hunted with restriction
Russia	30 000	stable but varying	unprotected
USA	9790 - 13 150	upward	hunted, protected
Saudi Arabia	600 - 700	stable	unprotected
Slovakia	350 - 400	downward	hunted, protected
Slovenia	50 - 100	stable	protected
Spain	2000	upward	hunted
Sweden	45 - 60	upward	protected
Switzerland	5	upward	protected
Ukraine	2000 - 3000	unknown	unknown

* Original data (50-100) corrected by new data (Kusak, not published).

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Outer appearance, physical features

			The grey wolf is the largest member of the dog family. The largest wolves live in the north (average weight = 41 kg - Alaska, Northwest Territory, Mech, 1970), whereas the representatives of more southern populations (India, Pakistan, Afghanistan) are half that size (Kumar, 1998). A full-grown wolf from the area of Croatia weighs 31 kg on average (Kusak, unpublished). From the top of the nose to the top of the tail wolves are 170 cm long on average (tail = 42 cm), with an average height of 70 cm measured on the ridge. The colour of the wolf's fur depends on the share of black, grey and brown covering hair. In Croatia wolves are always grey; the back and the tail have dark-grey colour turning into light-grey towards the belly and the legs. On the front side of the forearm there is usually a dark stripe, although certain specimens were found to have none (Kusak, unpublished).

	Various parts of the world are inhabited by wolves of a colour varying from white, through light-brown and reddish to grey and black (Mech, 1970). By his constitution the wolf is well-adapted to running, especially to a long-lasting trot. His rib cage is narrow, elbows retracted inwards and paws turned outwards. This enables the front and rear leg on one side to move in the same plane. He has four toes on the rear and five on the front legs, but steps never on the first toe of the front leg (big toe, inner side of the leg). His legs are comparatively longer than with other members of the dog family (Young, 1944) which contributes to the speed of moving over relatively long distances.

Since the wolf feeds almost exclusively on flesh, bones and other parts of bodies of animals he preys on, the build of his head facilitates catching and eating of the prey.

		The wolf's head is elongated forwards, it is 25 cm long and 14 cm wide on average. The brain volume is 150-170 cub. cm, exceeding the volume with the majority of dogs by at least 30 cub. cm. His massive jaws form a basis for strong masticatory muscles and 42 specialized teeth. The dental formula is I:3/3, C:1/1, P:4/4, M:2/3.The largest teeth are canines that serve for catching and killing the prey. With a full-grown wolf the spacing between the tops of upper canines is 45 mm and of lower canines 40 mm on average (Kusak, unpublished). For chewing and "cutting" of flesh and sinews the wolf mostly uses the fourth upper premolar and the first lower molar, acting as scissors, and for breaking the bones his strong molars. All wolf's senses, especially that of smell and hearing, are perfectly developed.

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Wolf's way of life

	In order to hunt a large prey predators must either be almost as large as their prey (for example, carnivores of the cat family) or can be smaller and hunt in packs (wolves, African wild dogs) which accounts for their evolutional success. Besides being able to catch a larger prey because they hunt in a group, they can also eat it up immediately and make full use of it. The group in which wolves live together is called a pack. The core of a pack consists of a reproductive pair and all other members of the packs, the young and their elder brothers, are the descendants of the same parents. The wolves travel, hunt, feed and rest in packs, which means they are together all the year round.


	In order to be able to carry out all of these activities successfully, the pack has a relatively complex social structure. The wolf pack is arranged in a hierarchical manner, with the pair of parents keeping the dominant position and other members of the pack building among themselves a relationship of superiority and subordination.The dominant wolf or she-wolf decides when the pack is going to hunt and where the lair will be situated, and the hierarchical structure is best seen when feeding on a prey: the subordinates eating after the superiors. Besides, a strong domination primarily in the female line makes the mating of subordinate members with each other or with one of the dominant wolves impossible. So only one she-wolf in a pack can have the young, which is one of the mechanisms to regulate the population size of this top predator. At the same time this prevents mating with kinship. The inability of mating and the lack of food force the subordinate wolves to leave the parent's pack and its territory. This happens mostly with young wolves at the age of two and three.

		In search of a new habitat and partner they leave for areas unknown to them, which is called dispersion. Wolves have a markedly territorial character; they mark the space they inhabit by urine, excrements, by scratching the soil and howling. By defending their living space from other wolves, they secure their prey. An alien wolf may enter the territory of a pack, but if found by the pack, he will almost surely be killed and sometimes eaten up. The same may happen to a dog entering the wolves' territory, because they will probably see him as an alien wolf.

Consequently, in wolf populations not affected by human activities as much as 65 to 70 per cent of the total wolf mortality are caused by other wolves. This is another mechanism for self-regulation of the wolf population.

If a wolf in dispersion succeeded in finding a space not inhabited by other wolf and containing enough prey, and if at least one young, not related wolf of opposite sex enters the same space, this will result in a new pack. After they come closer and socialize with one another, a new pair of wolves starts marking their new space with great intensity; they mate next winter and raise their first litter in spring (Mech, 1970; Mech and assoc., 1998).

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Reproduction of wolves

		The she-wolf is in heat once a year, in the period from the end of January till April, in northern parts later and in southern parts earlier. The heat lasts three weeks and the mating itself takes place in the third week. She is in cub for 63 days and bears the young in a lair that she has dug out earlier. If not disturbed in their lair, wolves can use it several years successively. The litter normally consists of 4 young who are blind and deaf until they are from 11 to 15 days old and suck until six to eight months of age when they start turning gradually to food brought to them by all other members of the pack.
	The place in which wolf-cubs live during growing up and to which full-grown wolves of the pack return every day is called a haunt. During summer wolf-cubs may be moved from one haunt to another a number of times. Until the first winter wolf-cubs reach the size of a full-grown wolf and start travelling with the pack. They are sexually mature at the age of 22 months after which they leave their pack (Mech, 1970; Garms. and Borm, 1981). back to the top

Wolf's habitat and diet

Wolves may live in any habitat that provides enough prey and shelter. To this very day wolves have managed to survive in hardly accessible areas and are therefore often seen as a symbol of wilderness. The wolf needs a shelter only to avoid humans, because he has no other enemies in nature. It turned out that wolves may live even very close to humans, in a cattle-raising area (Kusak, 2002), in a grain field or on the outskirts of a town.

This is possible if tolerated by humans and if the wolf mortality rate caused by man lies below the annual growth.

In such cases they can almost completely switch to feeding on domestic animals. So domestic animals (sheep, goat and to a lesser extent smaller cattle and dog) account for 84 per cent of the wolf's diet in the area of Dalmatia, as opposed to Gorski kotar where wild even-toed animals (doe, deer and wild boar to some extent) with their share of 77 per cent make the main wolf's prey.

The wolf's ecological niche is a "hunter of large mammals", meaning that his main prey are large cloven-hoofed mammals (Artiodactyla) and rarely those hoofed (Perissodactyla). The wolf will eat up any other animal he may catch too. It has long since been known that when hunting wolves choose the prey easier to catch at the particular moment (Mech, 1970; Frits and Mech, 1981), but this changes during the year (Mech and assoc., 1995). So in an ecosystem containing more types of prey they will hunt the type more readily available and therefore easily accessible, taking animals weakened by their age, illness and famine or the young (Ballard and assoc., 1981; Mech, 1970, 1998; Peterson, 1977). In this way wolves affect positively the health of the prey population and contribute to the stability of the entire ecosystem. Without predators the number of herbivores in unaffected ecosystems can increase to such an extent that it may result in the reduction of their nutritional basis (disturbance of forest restoration, even a complete defoliation up to creation of karst) which can ultimately lead to a considerable reduction in the number of herbivores themselves or their complete disappearance.

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