In several wildlife books I have encountered statements by scientists who have observed wolves and who have analyzed wolf diet (e.g., scats) claiming that ravens are (almost) never caught and eaten by wolves.
It is surprising because ravens are frequent companions of wolves and some of the most influential scavengers of wolf kills.
In fact, ravens might have been so influential as to affect the group size selection in wolves (Vucetich, J.A. et al., 2004).
However, it would appear that wolves rarely end up killing ravens (even if they chase ravens off the carcasses).
For example, in his book ‘Last Wild Wolves: Ghosts of the Rainforest’ (2007), Ian McAllister references the Canadian biologist Chris Darimont’s work in British Columbia as well as the American biologist L. David Mech’s work in Alaska, ‘Chris Darrimont’s dietary study analysed more than 3,300 scats collected from the outer coast, from islands like this one and up into the Coast Mountain, and the results show that a wide variety of birds, such as sandhill cranes, Canada geese, ducks, and herons are prey for wolves. But, surprisingly, not a single trace of raven has been found in wolf scat. Mech’s analysis of thousands of scats in Alaska from previous studies revealed the same’ (pp. 110).
Absence in scats does not necessarily represent absence in kills.
For example, as wolves would typically interact with ravens over the carcasses of more or less recently killed prey (or carcasses scavenged by wolves themselves), wolves might kill ravens in order to limit competition but they might not consume the killed ravens because it is not profitable and better meat is available.
However, during winter, any meat would probably become utilized by the wolves, and it would appear that observations of wild wolves killing ravens are scanty at best.
In the wild, the raven does not constitute a significant food resource, and thereby it might not pay off to invest energy in killing the raven and the wolves thereby stop at simply driving the birds away (minimum effort).
Meanwhile, I have seen at least several livestream videos in captive wolf facilities (e.g., International Wolf Center, Wolf Conservation Center etc.) where wolves have played with ravens, chased ravens, otherwise interacted with ravens and also where wolves have killed ravens.
I began wondering whether it might hold true that captive wolves have specialized in killing ravens.
Personally, I do not see why ravens in these conditions would be greatly more vulnerable to wolf predation than ravens out in the wild (from the perspective of environmental layout).
It might seem at first that wolves in the captive facilities have more energy to spend and as these wolves do not have to be as concerned over ‘the profitability’ of their actions (and interactions), wolves might have developed a raven-killing strategy in order to exercise their hunting instincts.
I believe it is important for animals not to lose the instincts that their ancestors have worked very hard to evolve in order to pass on to the future generations, and it is possible that wolves who cannot hunt, must somehow express these behaviours because it is not merely a mindset but a responsibility (granted that none of these wolves have probably given up the hope they might reproduce someday).
It would not be unfeasible that wolves in captivity attempted to redirect their wild skills and traits into other channels such as killing prey that would not be killed in the wild due to the poor return it provides in terms of nutrition.
The raven might be vulnerable not because of some environmental conditions but because the ravens might not have adapted to wolves actually attempting to kill them.
Ravens might have evolved responses to wolves who are, at the time, feeding or who already have fed and whose interest is to keep the ravens at bay and not to cross the threshold between a chase and a more intense pursuit.
Thus, ravens might not be prepared to meet a wolf who has, in its turn, developed new behaviours that surpass the ancient interactions.
Still, these ravens (especially, residents) would have had an opportunity to observe the wolves over time and to realize that these wolves somewhat differ from their wild peers.
Ravens have been watching wolves hunt for at least a million of years (possibly, three).
I find it difficult to assume that ravens would not have figured out wolf hunting strategies (e.g., body cues) even if they formerly used to apply to prey other than ravens.
My personal supposition as to why wolves kill ravens in captivity is a bit different.
I believe that those are not hunting instincts exclusively that wolves have a need to hone.
I believe that wolves have a natural sense of curiosity and as they find they have plenty of time on their hands, they might feel the need to satisfy that curiosity through exploration and play.
This could explain why I have observed more cases of wolves killing ravens in the International Wolf Center webcams compared to Wolf Conservation Center livestream.
The IWF hosts a captive pack which does not reproduce while the wolves at the WCC frequently comprise family units.
Wolves who are actively raising pups and managing a family dynamic might have less need (and time) to engage in recreational and educational activities.
Perhaps these wolves that are killing are not seeking to hunt the raven.
Perhaps they wish to study the raven or to play with it.
But, as the ravens (and other species) are familiar with wolves as hunters and less familiar with wolves as playmates or researchers, the ravens might become confounded and unable to read the non-predatory but still pursuit-like and close-contact-establishing behaviours of the captive wolves.
It has been stated that ravens do sometimes play with wolves also in the wild (especially, with pups).
However, it is possible that these interactions are limited in scope and that they mimick the predatory behaviour because, for example, pups, at the time, would be acquiring their skills as future hunters and, for a pup, it might be difficult to separate between hunting- and non-hunting-based play.
When wolves approach ravens to play and when wolves use behaviours that fall outside of the predatory routine, the ravens might become subject to injury or shock because they have been confused by the cues that the wolf is manifesting and that are, according to ravens – the close companions of the hunting wolf – ‘quite unwolfish’.
My assumption leads to another hypothesis which is that wolves do not use the same behaviours during play as they use during hunting (even if they are playing with potential prey).
When seeking contact with ravens, wolves might be using body language that is normally restricted to communication with other wolves or with non-animate objects.
Or perhaps there is a third type of body language that these captive wolves have evolved to interact with the world that has become energetically accessible for their intellectual pursuit.
Hunting routines often become embedded in play among wolves themselves, and it is, of course, possible that even if the wolf is not trying to hunt the raven but to simply play with it, through these hunting-play sequences, the play, unfortunately, turns into a killing.
However, I think that captive wolves are approaching the ravens in attempt to interact in a manner that does not resemble hunting (in the wolf’s mind) but that serve as an invitation to play together and to explore together.
And it is through these novel behaviours, wolves become misunderstood by the ravens who expect wolves to behave in a hunting manner to which the ravens know how to respond.
As the wolves exhibit behaviour that is not a hunting behaviour, nor it is based upon hunting, the ravens might become entirely perplexed and perhaps too scared or too aggressive to interact without hurting the wolf or hurting themselves, i.e., without escalating the interaction into an actual conflict.
My theory is that captive wolves develop intellectual pursuits that they no longer base in typical wild wolf behaviours and that are not predatory in nature, nor they mimick predation (as play).
Through these novel behaviours, wolves startle and confuse their interactive partners who misperceive the wolf’s intent without being able to respond to it (as such a response is not yet made available within the scope of their ancient relationship).
By trying not to hunt the raven, the captive wolf might have turned a proficient raven hunter.
HERE is an Explore Live Nature Cams video of a captive wolf (IWC) snatching a raven our the air, and THIS is a video recorded by IWC livecame watcher DebI where several efforts by a captive wolf to interact with ravens can be observed.
References
McAllister, I. (2007). The last wild wolves: ghosts of the rain forest . University of California Press.
Vucetich, J.A. et al. Raven scavenging favours group foraging in wolves, Animal Behaviour, Volume 67, Issue 6, 2004, pp. 1117-1126, ISSN 0003-3472, https://doi.org/10.1016/j.anbehav.2003.06.018
Notes by Ieva 