Lois, Founder and Director of the White Wolf Sanctuary, would always describe the wolves to visitors as monogamous. While in wild groups this is not always the case, in low-density wild populations such as the wolf population on Ellesmere Island (where arctic wolves are endemic), mating for life is the norm. A breeding wolf may take another mate in higher density populations, but animals tend to be monogamous as long as three conditions are met:
1) Offspring are not reproductively mature,
2) Breeders are more attracted to each other than they are to offspring,
3) Courtship between siblings is interrupted.
Incest is not common in wild wolves, especially when mates other than close relatives are available. The wolves at the White Wolf Sanctuary would sometimes be kept in related pairs – for example, Modoc and Sakarri, Tehalin and Nike, where both pairs are brother and sister. Unlike dogs, though, true wolves only breed once a year – thus pairs would be separated for about a week during February when they would naturally breed in the wild. During the rest of the year the animals could be kept in related pairs with no risk of breeding with each other.
Wild female wolves don’t ovulate until their second, third or fourth winter, thus are usually 2-5 years of age when delivering their first litter of pups. The ability to reproduce may be hampered by nutritional or other stress, or social reasons (i.e. living in a pack that already has a breeding female).
Ovulation occurs in response to a range of natural cues. For example, in autumn as temperatures become cooler males will experience a rise in testosterone, and estrogen levels in females will increase: this primes the reproductive organs. These seasonal changes in reproductive hormones are correlated with peaks of reproductive behaviour. What follows is the standard reproductive cycle; proestrus, oestrus (heat), metoestrus (pregnancy or pseudopregnancy), and anoestrus after pups are born and cared for. The duration of each phase varies among individuals and may depend on different factors such as age, experience and body condition.
Proestrus: This is the period directly before oestrus, and in females a bloody vaginal discharge can be seen, coinciding with a continuing rise of estrogen levels. Behaviour-wise, females will show more attention to their mate, often prancing, nuzzling, body-rubbing and pawing him. Males will show more of an interest in scents in the urine of their mates.
Oestrus: Also known as ‘heat’, this phase is when female canids are receptive to mating. In experienced pairs oestrus tends to last less than a week, but inexperienced mated pairs may observe oestrus for over two weeks.
Metoestrus: The phase of sexual inactivity following oestrus where progesterone levels reach a peak – i.e. pregnancy. Metoestrus females who are not pregnant are said to be experiencing ‘pseudopregnancy’: they may still show behavioural and physical signs associated with actual pregnancy, e.g. loss of belly hair, small growth of mammary tissue, den construction behaviour and pup care.
In other species, once impregnating a female the male may then find another to mate with. However, because female wolves are only sexually receptive for a short amount of time, the success for a male wolf to find another mate is unlikely. Thus, it is of no negative consequence or loss for a male to remain with his current mate. He will instead assist in pup care – either directly (by delivering food to new pups) or indirectly (through den preparation, pup defense, and delivering food to the breeding female).
Anoestrus: A period of complete sexual inactivity before the next proestrus phase.
Gestation in wolves is 61-64 days. With wolves copulating in winter, pups are born early enough in spring that it coincides with a birth pulse of herbivores (relatively easy prey for wolf parents to catch), and late enough to escape the worst of winter weather. When pups are born, they are extremely dependant on their carers. Their eyes are closed, their legs are small and uncoordinated, and their capabilities do not stretch much further than being able to feed and knead their mother’s belly. They can also react to a range of stimuli such as temperature and pain; they can direct themselves towards a heat source, cry with pain and whimper when cold or hungry. This is the ‘neonatal’ period. Like kittens, they also require stimulation to defecate and urinate; i.e. their mother licking their hindquarters. Mothers also keep the den clean where the pups will stay until they are a few weeks old.
Dens are dug away from the peripheral edges of territories where hostile encounters with neighbouring packs are most likely. They are generally built near water and areas with adequate shelter, such as under a tree with a sturdy root system. Wolf pack members of both sexes and social status may assist with den construction.
After the neonatal period, the next phase of a pup’s life is sometimes known as the ‘transition’ period. This is the phase at which their development is most rapid. Their eyes open at 12-14 days, and they are able to stand at walk. They naturally explore, at first the inner den, and then around its entrance where they begin to eliminate instead of inside the den. This exploration defines their main movements for the first 8 weeks with their mother still moving them between dens if she sees fit. From 8 to 20 weeks the pups inhabit an area above the ground that includes the den, a site (often known as a ‘nest’) where they huddle together, a network of trails to explore and various play areas. These general areas are known as ‘homesites’. Play is an extremely important of pup development. Each is born with the innate response to chase and capture small moving animals – such behaviours are the introduction to hunting techniques.
They also learn a great deal about appropriate social interactions, they learn to recognise each individual pack member and also how to use different vocalisations for different situations. They begin to form a ‘following’ behaviour, whereby if a pup sees an adult wolf moving somewhere in a purposeful manner, or if their mother suddenly interrupts a feeding session and moves away, they will follow. This behaviour eventually develops to pups recognising that adults will lead them to a carcass, but not until they are much more mobile.
At about five weeks of age pups have fully developed sensory systems and their gastric systems are developed enough to allow them to digest solid food. However, at this stage they still lack the bite strength required to adequately chew large pieces of meat, thus milk remains a nutritional alternative. Adults also regurgitate food to pups. Pups are able to prompt regurgitation by poking their muzzles around an adult pack member’s mouth – this behaviour is known as “licking-up”. Licking-up automatically cause an adult with a full belly to regurgitate food. Pups also learn to follow these adults, and thus are directed to carcasses.
Pups learn to cache food from an early age and in times of food surplus will store extra food for times when they are hungry or on a day when little is delivered from adults.
At 3 months of age, pups remain less at homesites on their own and spend more time on expeditions with pack members.
Between 4 and 10 months of age juvenile wolves are mobile enough to join adults on hunts even though they have not attained full body size. They learn hunting techniques by shadowing other pack members. Complex steps such as where to find prey, how to kill and how to avoid risks need to be learnt.
The wolf pack is a (usually) family group that moves within an exclusive home range and is hostile to strangers from neighbouring packs. Through a complex range of cohesive and conflictive behaviours (where cohesive behaviours bring wolves closer together, and conflictive behaviours drive them away from sharing within a family) they maintain a dominance hierarchy and a varying population number.
Although the basic family ties in a pack promote cohesion between individuals, each wolf must ensure its own survival first – otherwise it will be of no use to relatives. Remember that it is each wolf’s “goal” to reproduce; this is one defining factor of an animal’s interactions with pack members.
A linear dominance hierarchy is the most common way of describing conflict behaviour in a wolf pack.
Alpha male -> alpha female -> beta -> gamma -> omega.
Where: The “alpha” wolf is the individual that wins fights over all others. The “beta” loses fights with the alpha but wins over all others, and so on, down to the “omega” wolf that is most likely to lose any fight. This model used to be the basis for basic understanding of wolf relationships, but researchers are now turning away from the “alpha” theory, and more suggesting that breeding animals in a pack are not necessarily the most dominant or aggressive; they just happen to have filled the breeding individual spaces. The reality is also that in most wolf packs family dynamics are more complex than a linear hierarchy, and can often change. Factors such as sex, age, individual temperament, conflict cause and context, nutritional availability and social experience are examples of a range of values that may be difficult to scientifically measure alone, not to mention all together. The two main dynamic factors that affect relationships are competition for food, and sexual maturation of offspring. As discussed previously, in times of food shortage higher levels of aggression are seen between pack members and these are times where yearlings or offspring from previous litters tend to disperse from packs.
At the White Wolf Sanctuary, Odot was initially recognised as the “alpha” male when all individuals ran in a single pack. Although they had since been separated into pairs, he always held a dominant stature – wolves at fencelines would often back down from him at just a stare, his tail was always held high and he always walked with purpose. His interactions with Tamahawk (his paired mate) were hilarious; although she was a very small wolf, she would still life her leg to urinate (as a more dominant wolf would), and at times when whole roadkill was available she would pick up massive limbs from carcasses and throw them into the air around her, demonstrating her strength. She seemed to be the only one who would actually stand up against him – this often resulted in very loud arguments of conflict.
It was also obvious that the other young members of the Sanctuary were becoming increasingly mature and would vie for dominance themselves. Even Modoc, who was often quiet, would stick his tail up and wolf-bark at the fence against his brother and sister. It was very easy to see how in the wild there would be great opportunity for situations of conflict, until lower-ranking wolves would accept their stature and eventually disperse.
For this and other information see:
Behavior, Ecology and Conservation
Edited by L. David Mech and Luigi Boitani