Winter Wolf Syndrome…

Is it real? What does it even mean? When and why does it happen?

Is “Winter Wolf Syndrome” real?

The short answer is: For the most part, No. It’s absolutely normal for seasonally reproducing species to become, in general, grouchier and more reactive than usual leading up to and during their breeding season.

Being grouchy and more reactive during breeding season is NOT the same as a wolf or high content wolfdog with mental or emotional trauma, or legitimate behavioral abnormalities, who is fully committed to trying to severely maim or kill anyone or anything that upsets them. That type of behavior is very rare and is not normal.

The long answer: “Winter Wolf Syndrome” is a made-up concept. It is not a medical or scientific term in any way. The hormonal and behavioral changes that wolves and higher content wolfdogs experience and express leading up to and during breeding season is a natural, normal biological process that wolfdog owners must understand and be prepared for.

The term “Winter Wolf Syndrome” originated with the story of a pure wolf named Two Feathers, way back when owning pure wolves was largely legal in the USA about 30-40 years ago. This wolf was a VERY confident and pushy animal, even outside of breeding season. Once he sexually matured and became even more assertive and grouchy during the breeding season, his owners severely mishandled and mismanaged him out of frustration and anger, even going so far as to shout at him and hit his fence. This antagonization only made matters worse, quickly resulting in an animal who would charge and attack the fence with lethal intentions towards his owners and other humans. His owners’ mismanagement of their animal ultimately destroyed Two Feathers’ trust in humans and created an animal who was legitimately dangerous to interact with. His siblings, who were raised and treated with the respect they needed and deserved, never had this issue and were well known for their good temperaments.

The online wolfdog community has been using the term “Winter Wolf Syndrome” as a kind of buzzword for years to (mistakenly) refer to any wolfdog - of any content - who seems to become even slightly grouchy during the breeding season. Winter Wolf Syndrome really only refers to high contents (85-99% Gray Wolf) or pure wolves who:

  1. Seasonally reproduce and experience a massive surge of sex hormones leading up to and during breeding season;

  2. Are extremely confident, pushy, or rude animals who have learned that they are able to use intimidation or force to get what they want, even during non-breeding months;

  3. Have emotional and/or mental trauma or legitimate behavioral abnormalities which result in the animal becoming extremely overly-reactive during breeding season;

  4. Become so agitated and reactive leading up to and during breeding season that they resort to attempting to severely maim or kill anyone or anything that upsets them.

Wolf Reproduction

Although most breeds of domestic dogs are able to reproduce year round, with males producing sperm 365 days a year, and females often going through estrus (having a heat) two or more times a year at any time in the year, fertility works quite a bit differently in wolves and higher percentage wolfdogs.

In wolves, both males and females are only fertile during a specific time, with mating taking place between the months of January through March. This season of fertility is controlled by photoperiodism, or the physiological reaction that an animal has to the amount of sunlight received through their eyes, which is controlled by the seasonal fluctuations in light and dark periods that the earth experiences each year.

Outside of breeding season, during the long days and short nights of summer through fall, male wolves do not produce sperm and their testes shrink to the size of small grapes. Their testosterone levels are extremely low, around 10 ng/dl (nanograms per deciliter). As the days shorten and nights get longer, male wolves begin to produce increased amounts of LH (luteinizing hormone) and testosterone. This triggers spermatogenesis to begin and the testes increase in size to roughly the size of a golf ball. Peak testosterone levels, which occur between December through March, can reach up to 560 ng/dl, which represents a 5,500% increase in testosterone levels between non-breeding vs breeding months! (Ever heard of roid rage? Maybe this can help bring a male wolf’s seasonal grouchies into better perspective!)

Female wolves only experience one estrus cycle per year. Wild female wolves typically do not experience their first estrus until they are 22 months of age or later, although captive bred wolves have been documented as having their first estrus as early as 10 months (during their first winter). To contrast, most domesticated dogs can experience their first estrus cycle as early as 6 months of age, and can have 2 or more estrus cycles per year, at any time of the year.

The estrus cycle for female canids consists of four stages, Proestrus, Estrus, Metestrus, and Anestrus. Female wolves experience a longer Proestrus period compared to domestic dogs (about double the length), which can range from 15 days up to 60 days. This stage of the estrus cycle is when female wolves begin to secrete sexual hormones to signal males that they are nearing peak fertility, and they begin to display courtship behaviors. Estrus is when the female ovulates, due to elevating progesterone levels and an LH surge that triggers the release and ripening of eggs for the purpose of fertilization. She is receptive to breeding during this time. This stage can last anywhere from 9 to 15 days in wolves. Metestrus (also known as Diestrus) is the period after the female ovulates, and lasts for the duration of a normal pregnancy (56 to 68 days). Both pregnant and non-pregnant wolves experience the same elevated progesterone levels and gradual increase in prolactin levels during this stage. Anestrus is the period of time when the female wolf is non-fertile, which lasts from June to December.

Both male and female wolves experience elevated levels of prolactin for several months following breeding season. This hormone is highly influential in eliciting parental behaviors in all wolves in a pack, which help them to be accepting of, and willing to help raise, any puppies born to the pack each spring.

Wolfdog Reproduction

Wolfdogs in general can exhibit a wide range of reproductive capabilities and behaviors, but in general, the higher the percentage of wolf, the more likely the wolfdog is to follow the same breeding cycle as pure wolves. High content wolfdogs, as a rule, tend to follow almost exactly the same breeding cycle as pure wolves, with breeding taking place between January to March, and litters being whelped between March to May. Wolfdogs with heavy Arctic Wolf (Canis lupus arctos) influence in their pedigree may whelp as late as June, due to the later spring that the arctic circle experiences, compared to more southern wolf habitats. There has been the very rare occurrence of verified high content wolfdogs (85% to 99% Gray Wolf) reproducing outside of the normal breeding season, but these instances are unusual and irregular.

Mid to Upper Mid content wolfdogs may also reproduce seasonally, but their timing may be “off” by several months compared to pure wolves. There are many mid contents who will experience peak fertility in late summer or early fall, to have late fall or early winter litters. There are also quite a few mid content wolfdogs who follow the reproductive timing of the domestic dog breeds they are mixed with, with males remaining fertile year-round and females able to have heats at any month of the year and/or more than one heat per year.

Low contents are most likely going to follow the reproductive timing of domestic dogs, with males being fertile year-round and females able to have heats at any month of the year and/or more than one heat per year. There are some low content females who are still monestrous (only having one heat per year), but this heat may occur at any month of the year.

Owners of wolfdogs should be particularly careful to monitor their animals and watch for signs of their dog being capable/receptive of breeding. Responsible owners will keep their intact wolfdogs separated during a female’s estrus cycle, to prevent unwanted or unplanned litters. Sterilization of wolfdogs is generally recommended for several reasons. Primarily, to prevent accidental or irresponsible breeding from occurring. Spayed and neutered animals cannot produce unwanted or unplanned litters. Secondarily, however, spaying or neutering may also serve to reduce some of the hormonal fluctuations that a wolfdog experiences around their fertile periods, and may help to prevent undesirable sexually-related behaviors. Please note that there are quite a few spayed/neutered mid and high content wolfdogs who DO still experience enough hormonal fluctuation during breeding season to affect their behaviors. Spaying and neutering is not a guarantee for preventing seasonal grouchies, but may lessen it significantly.