“Wolves may not be close to us taxonomically, but ecologically their behaviour in a social structure is remarkably close to that of humans. That’s why we domesticated dogs – they are very similar to us.” By Kershenbaum (Anon., 2016).
The wolf is well known to be the consequence and cause of kill rates, like wolfs other large mammalian predators are highly adaptable and learned to avoid human activity, and inhabit environments where their prey breeds once a year, therefore it is necessary to understand how the kill rates vary from each year to know their predation and since their habitats are temperate in climate, the environment is covered in snow making the kill sites easily detected (Ausband, et al., 2010)(Metz, et al., 2011).
Prey
The elk which is one of the natural prey for wolves move closer to the tree line in their presence, the female elk increase vigilance behaviour rather than males, making wolves pick males to be their prey in the winter due to the worse body condition than cows (Winnie and Creel, 2007).
Evolution
Eastern North America, was historically inhabited by wolves such as eastern timber wolfs (Canis lupus lycaon) which is a subspecies of grey wolfs (Canis lupus) in the north, and in the south, by the red wolfs (Canis rufus) both are taxonomically distinct from coyotes (Canis lantras), despite the difference, hybridisation between timber wolfs and coyotes has been identified and for that reason has been suggested that the red wolf is a result of the intensive breading between Canis lupus and Canis latrans (Wilson, et al., 2003).
Mitochondrial DNA sequence of a population of Canis lupus lycaon from the 1960s and captive Canis Rufus was analysed and compared with Canis latrans DNA and it was suggested that the Canis lupus lycaon had diverged from Canis lantras 150 to 300 thousand years ago, on the other hand, Canis lupus evolved in Eurasia and went to North America 300 thousand years ago and it has 1 to 2 million years divergence from Canis latrans (Wilson, et al., 2003).
The analyses of the two Canis lupus lycaon specimens from the 1960s which were killed 40 years prior of supposed Canis latrans arrival to the area, were determined to have a sequence of genes that compared with the Canis latrans showed consistent patterns rather than in comparison with the Canis lupus, this can be explained by the hybridization of Canis latrans with Canis lupus lycaon due to the similarity of the genes or another possible explanation would be the presence of a common ancestor (Wilson, et al., 2003). Both Canis lupus lycaon and Canis rufus present a presence of a wolf that is not Canis lupus origin, this shows emerging evidence that the Canis lupus and Canis lupus lycaon can hybridize, therefore these eastern species have evolved from a wolf with an independent evolutionary history from the Canis lupus (Wilson, et al., 2003).
Environment and the wolf
Foraging may vary from seasons and it is an important aspect in social carnivores kill count estimation, in previous studies shown that the larger the pack is, the lower will be the amount of food available per wolf, during the summer and winter (Metz, et al., 2011).
During the summer the majority of wolves acquire an excess of biomass than needed on average of 4.5 kg/wolf/day, which is 25% greater than the biomass needed to meet their energetic requirements 3.6kg/wolf/day, despite the biomass excess in the summer wolfs lose weight, a possible reason would be that wolves lose much of what they need to scavengers like bears which play an important role of scavenging during the summer, for this reason, the wolfs in Yellowstone park would consume biomass near their minimum requirement (Metz, et al., 2011).
While looking for food, wolfs pack with pups that are too small to travel will be relocated to sites other than the dens, until the adults return, this sites will change over the several of weeks during summer, in particular, North America wolfs normally use meadows for this sites due to the hypothesis that pups would have prey that could consume such as small mammals and insect, but also the tall grass would provide shelter preventing potential predators from finding them and nearby water source would help digestion of the high protein diet (Ausband, et al., 2010).
Being a social carnivore, howling plays an important part in communication between the alpha pair and the rest of the pack, and if the alpha pair is removed the howling would increase in response to the stress, therefore howling may not necessarily indicate an emotional response to changes in the environment (Mazzini, et al., 2013).
Conservation
The hybridisation of wolfs and coyotes brings a new meaning to the conservation of these species, on which species of wolf should be reintroduced to the habitat, which according to the studies the timber wolf is suitable for the reintroduction to the states (Wilson, et al., 2003).
A common way of monitoring wolfs is the use of GPS collars due to the large territory they inhabit being remote and inaccessible in its majority, and it is used to estimate kill rates but wolf per capita kills are calculated by the number of prey killed by the pack, therefore only one member of the pack needs to have the GPS collar to detect the kill sites, which are already used in Idaho for Canis lupus monitoring, although it has some disadvantages that need to take in consideration, although it lives in groups in some occasions wolves separate from the pack to forage, especially in the summer, also if packs size increases it makes it less cohesive but also is an expensive method of tracking the number of wolves, making collars limited. (Metz, et al., 2011)(Ausband, et al., 2010).
During the winter, the monitor techniques can become more efficient due to the animal congregation due to elk populations during winter, proposing another conservation technique, aerial track, this technology would only be a benefit in the snow-covered ground during winter, but in snow conditions can be inconsistent and the habitats might not be in open spaces, therefore the GPS collars would be the best way to predict the predation levels although since it is an estimate is uncertain until what point the metabolic needs were meet (Metz, et al., 2011)(Ausband, et al., 2010).
By analysing the howls of a pack of wolfs its possible to identify the species, for example, Canis lupus lycaon have a heavy with low flat howls on the contrary red wolfs have a more high looping vocal tone, therefore each species has its identifiable howl which could better track wild wolf populations (Anon., 2016).
Wolfs are an important part of the ecosystem due to its impact on the elk population in North America and provide resources to other organisms such as bears and despite the hybridisation with Canis lantras, the numbers of wolf populations are establishing with the reintroduction and management of these species.
References
Anonymous, 2016. Wolf Species Have “Howling Dialects”. 53(8)
Ausband, D.E., Mitchell, M.S., Doherty, K., Zager, P., Mack, C.M., 2010. Surveying Predicted Rendezvous Sites to Monitor Gray Wolf Populations. 74(5), pp. 1043-1049
Vienne, D.D, 2016. Lifemap - Tree of Life. 20/04 Available at: https://play.google.com/store/apps/details?id=fr.univ_lyon1.lifemapcom&hl=en_GB [Acessed 21/06/2020]
Mazzini, F., Towsend, S.W., Viranyi, Z., Range, F., 2013. Wolf Howling Is Relationship Quality Rather Than Underlying Emotional Stress. 23(17)
Metz, M.C., Vucetich, J.A., Smith, D.W., Stahler, D.R., Peterson, R.O., 2011. Effect of Sociality and Season on Gray wolf (Canis lupus) Foraging Behavior: Implications for Estimating Summer Kill Rate. 6(3).
Wilson, P.J., Grewal, S., McFadden, T., Chambers, R.C., White, B.N., 2003. Mitochondrial DNA extracted from eastern North American wolves killed in the 1800s is not of gray wolf origin. 81(5)
Winnie, J., Creel, S., 2007. Sex-specific behavioural responses of elk to spatial and temporal variation in the threat of wolf. Elsevier, [e-journal] 73(1). Abstract only. Available through: ARU library website: http://library.aru.ac.uk [Accessed on 20/06/2020]