Mating Relations

Wolves tend to be monogamous. They mate for life and if one partner dies the surviving wolf will likely look for another mate. However, at the same time as raising one family, some male wolves will mate with a second female and help raise her family too. Whether a wolf raises a second family depends on taking advantage of mating opportunities and a plentiful supply of food to sustain another female and her cubs. When mates and food are sparse, males and females are more restrained. In addition, as in human relations, wolf pairs sometimes split up. Like human relationships, wolf mating arrangements are flexible within certain limits.

Sexual Maturity

Wolves in the wild tend to breed at some point after their second year. Many females probably do not begin to raise their first family until they are four or five, possibly a reflection of the difficulty of gaining a mate and a territory to settle on.

Breeding Monopoly & Multiple Litters  

Usually only the alpha wolves of a wolf pack breed (see Command & Control.      The alpha wolves monopolise the breeding by discouraging and obstructing the other adults: the alpha male restricts adult males and the alpha female restrains adult females. But a second female in the pack may also produce cubs in periods with plentiful food. She might be a daughter of the pack's alpha wolves and be mated by an unrelated male from outside the pack. Or she might be an unrelated incomer and pair with one of the alpha wolves' adult offspring. Either way her offspring are the alpha wolves' grandcubs. More rarely even three litters might be born to a pack in the same season.

However, the alpha wolves claim first choice of food for themselves and their cubs of the year when prey are hard to find. A female with an extra litter will then be unlikely to see her cubs survive.

Incest

Most adult offspring in a pack disperse (see Dispersal below), but others may remain with their pack well into sexual maturity. So this raises the question of incest and its deleterious consequences.

There seem to be opportunities for incest in a wolf pack. If a parent dies, might the vacant position be taken by one of the parent's offspring? Instead of dispersing, might a young adult challenge a parent and forcibly take the parent's place? The possibility also arises that two dispersing siblings might start a new pack together. Any of these options might be easier for a young wolf than to strike out alone in the hope of coming across a partner and finding a territory in the face of a hostile world.

Wolves are known to mate incestuously when they cannot meet new wolves. Incestuous matings occur when wolves are held in captivity. Wolves also mate incestuously where outbreeding is close to impossible on semi-isolated islands. The wolves on Minong (Isle Royale), in Lake Superior, have been closely observed for the last 50 years. Minong is only infrequently linked to the mainland by ice in some winters so its population of a few dozen wolves are isolated. Wolves on some Aleutian islands have also been observed in a similar position.

However, field studies find that alpha pairs are ordinarily unrelated and that their offspring rarely take their place. Given that the opportunities for incestuous relationships exist, yet are not usually taken up, it seems that wolves actively avoid incestuous relationships. The main behaviour by which wolves avoid incest appears to be dispersal (see below).

The Breeding Season

The mating season starts in the winter from about January and continues for roughly a month. Females come into oestrus at this time for five to ten days. Fertilised females produce cubs in the spring.

The time of breeding corresponds to the part of the year when hunting is easiest. Parents are therefore relatively well fed and in peak condition for the task of bringing up a family. Foetuses will be well nourished in the womb and cubs in the den may have ample food.

Onset of breeding activity relates to latitude. Wolves living geographically further north start breeding later than in southerly climes. Arctic wolves give birth as late as May to June. They also have fewer cubs on average than their more southerly neighbours.

Bonking & Birth

After the male ejaculates he turns around 180 degrees and faces away from his mate. But he cannot extract himself and the two remain joined in a copulatory lock for up to thirty minutes. The speculation is that this is nature's way for ensuring his sperm get a head start on their way along the fallopian tubes to fertilise the ova in the teeth of competition from other males who might sneak in a quick ejaculation. Copulatory locks are common in the canids.

Gestation lasts about 60 days. Five or six cubs are born on average, in early spring (April-May), but litter size can range up to eleven or so cubs. Their mother lactates eight to ten weeks. The cubs rely on her milk for their first month then are gradually weaned on regurgitated meat.

Pseudopregancy

A female in pseudopregnancy undergoes the same changes as in normal pregnancy, including preparation for milk production, but no foetuses develop because she has not been impregnated. Non-alpha adult females in captive wolf packs can be pseudopregnant each year. Therefore it is possible that wild-living female wolves also go through pseudopregnancies.

What is the point of pseudopregnancy? One or more pseudopregnant females in a pack might be advantageous for their mother, their pregnant alpha female. If she cannot suckle her cubs because she is sick, injured or dead, one of her adult daughters could take over suckling and the cubs would not starve. So pseudopregnancy might prepare adult daughters for surrogate motherhood. One venerable mother wolf was especially celebrated in the ancient world for her suckling propensities, being the stand-in mother of Romulus and Remus, the traditional founders of Rome.

Dens

Wolves give birth in the open when there is absolutely no cover. But being exposed to the elements their cubs are likely to die. So for the first six weeks after birth the cubs are usually reared in a den.

A den must be selected and prepared each breeding season to shelter the cubs and is commonly a hole in the ground, a cave or a crevice in rocks. But wolves make use of whatever they find in their environment, be it a hollow log, the roots of an up-turned tree or even an abandoned beaver lodge high and dry. Wolves dig their own den or take over a den from another species, expelling any resident foxes, coyotes, or other animal, and enlarge the den as necessary.

A wolf pack may occupy the same den each year, sometimes for several years in a row. Some wolf dens are known to be at least generations old and substantial rock dens may be occupied by wolves for centuries. Wolf dens can also be very transient. Wolves in the Arctic, if they are not lucky enough to find a more protected den, cannot dig in the ground because it is so frozen and have to make do by clawing out a shallow hollow.

More than one den may be used in the course of a breeding season. In that case the mother carries her cubs one at a time to the new den. If the cubs are older, she leads them with the whole pack travelling together in single file to their new site.

Cub Care

Cubs cannot maintain their body heat for their first three weeks of life, so their mother must stay with them in the den the whole time to keep them warm with her own body heat. This is why giving birth in a den tucked away from the elements is so important.

Having a mate is also essential for a nursing mother wolf. She cannot leave the den to hunt or her cubs may chill and die of hypothermia. So she is dependent for food on her mate and any other adult wolves in the pack. She stands little chance of raising her cubs alone should her mate die and there are no other pack helpers.

Wolves take great care of their cubs. Both parents share in the task of raising them. And their adult offspring who are still with the pack, the cubs' brothers and sisters, are devoted to the cubs, taking as much care of them as their parents do. All the wolves bring the cubs food from the hunt, play with them, guard them from danger and generally tend to them. When the cubs grow up they may also help care for the next generation their parents bear.

Cub Growth

Wolf cubs reach full size within 12 months of birth or at most after 24 months. This is accomplished by increasing their birth weight, roughly half a kilogram (a pound), about 60 times over. But at birth they can only squeak and are born blind and deaf. After two weeks their eyes open and after three to four weeks they begin to hear and their milk teeth break through their gums. They are physically strong for their size and can crawl about and struggle with each other for the best teats to suckle. Their large eyes and short muzzle on a soft round furry body arouse in humans feelings of cuteness and of kindness towards them, and probably does in wolves too.

In the cubs' fourth week their mother begins to venture out of the den to get food for herself. At about this time the cubs emerge from the den and begin weaning on regurgitated food brought back by the pack's adults from their hunts. When the returning adults approach the den, the cubs rush at them excitedly expecting food. Cubs can get a second helping from food-bearing wolves if they eagerly pester them by licking the adults' mouths, as this stimulates regurgitation.

By five weeks of age, when the adults set off on a hunt, the cubs scurry along behind them a little way before eventually giving up and returning home. At eight to nine weeks of age the cubs are fully weaned and weigh about 7-10 kg (15-20 lbs) - the weight of a large portly domestic cat. Their ears, snouts and bodies stretch out as the cubs begin to lose their rounded looks and resemble the adults more. The cubs are now old enough to accompany the grown-ups, although they are not yet ready to take part in hunts. Finally the whole pack abandons the den for a rendezvous site.

Rendezvous Sites

The juvenile cubs leave their den and follow the adults to the area where they are presently hunting and a temporary den is set up for the cubs there. This den is the wolves' so called rendezvous site. It is where the hunting wolves return from their trips to bring food for the waiting youngsters. It has the advantage of being closer to wherever the adults are hunting, which can be over 30 kilometres (20 miles) from the original den, so that returning to the cubs is easier. Sometimes the wolves on a hunt call the cubs to their kill if it is substantial, like a moose, rather than dismember and carry the pieces miles to the cubs. This place might then turn into a new rendezvous site.

The wolves typically make a rendezvous site where there is some cover, like a thicket, boulders or an opening in the ground, so long as it is big enough to accommodate all the cubs. One of the adults watches over the cubs at the site while the other adults are away hunting. The cubs explore their surrounds and the site gradually fills with their scats, chewed bones and worn down trails leading all around. At other times the cubs sleep or doze on top of each other to keep warm while waiting for the returning hunters.

When the adults set off on a hunt, the juveniles tag along as far as they can before giving up and going home. Eventually they manage to keep up with the adults all the way. This is when they start taking part on the hunt and abandon the rendezvous site. A late developing or sick cub, however, may be left behind. An adult will bring the cub food from time to time, but visits drop off as the pack hunts increasingly further away and the cub will die unless he can make good.

Dispersal

A pack cannot increase in size forever. And young adults need to find mates. So young wolves must disperse. It is through dispersing individuals finding mates that a wolf pack avoids inbreeding, how a wolf population maintains its genetic diversity by reshuffling its genes, and how wolves colonise new distant places.

Most offspring leave home before they are two years of age. A few might leave as young as nine months. Almost all are gone before they are three years old. The exception is if a parent dies or is displaced and an offspring takes over that position.

Dispersing wolves depart in all directions but leave their pack as solo adventurers. Several wolves in North America have been recorded moving anything from just a few kilometres (going just 'next door') up to 160 kilometres (100 miles) from their natal packs. But one wolf in Alaska logged 700 kilometres (435 miles) and another wolf in North America, who perhaps takes the record, covered 880 kilometres (550 miles). All these are straight-line distances. The wolves doubtless travelled at least twice as far taking into account twists, turns, ups and downs and backtracking.

Whether To Disperse

Whether a young wolf decides to stay or leave the pack depends on the interplay of several factors. An important determinant is wolf density and, related to it, the availability of vacant space for a territory. In a region saturated with wolves there will be no free space. Young wolves may make forays into the surrounds or make more sustained efforts but fail to get a foothold somewhere and return home. If accepted back they may postpone leaving home again until the situation changes.

Prey availability is another important element. When food is limited the parents insure their cubs of the year feed before their older offspring get their fill. Their grown offspring then have a strong stimulus to leave the pack and fend for themselves if they are to get enough food. This feeding order was well made by David Mech in his book The Wolves of Denali. He inspected the remains of four wolves trappers had caught. As they were trapped in the same part of his study area they were presumably from the same pack: an adult male, two cubs and a yearling. The former were well covered with fat but the yearling was scrawny.

Lone Wolves

What happens to dispersing wolves who cannot find a mate and territory? What happens to them if they do not return home? What happens to them if they return home but are rejected by their former pack? They become 'lone' wolves, not living in a pack but surviving on the edge of established wolf pack territories, waiting until conditions improve for them.

Lone wolves keep out of the way of resident packs, they risk being killed by them if they do not, while at the same time try to find enough food to live on. Many dispersing wolves are unsuccessful and simply die - like seeds scattered in the wind falling on stony ground. Lone wolves have low survival rates. In any wolf population some five to twenty percent of wolves are lone wolves.