Friday, October 24, 2008

Salmons for Grizzly Bears? Wolves love Salmons too.

It is very easy to think that major consumers of tetrapods are either us, humans and grizzly bears. Chris T Darimont, Paul C Paquet, and Thomas E Reimchen from British Columbia recently added one more species, Canis lupus, to the list.

According to the research done by Darimont, Paquet, and Reimchen, Canis lupus, Commonly known as wolves, preferred salmons over deers if the two preys were available at the same time.

The study was done in eight groups of wolves living along the central coastline of British Columbia for three seasons in four year periods. Researchers analyzed contents of wolf feces and hairs. Comparing feces contents to what nutrients are available from which preys, Researchers determined the change in dietary behaviors of the wolves.

From the winter through the summer, 80%~90% of wolves were found to consume deers; however, 40%~70% of wolves hunted salmons during the fall. During the periods of the research, deer availability did not vary from one wolf group to the others. And as one may know already, salmons were available to wolves only in the autumn. Scientists could conclude using these data that salmon eating behavior depends on salmon availability rather than on deer availability.

The researchers suggested that this study may help explaining the cause of declining numbers of salmons.

Research Article from BioMed Central
Spawning salmon disrupt trophic coupling between wolves and
ungulate prey in coastal British Columbia

Posted by: Yi, Jeongsang (6)

Update (10/28):

According to the research done by Darimont, Paquet, and Reimchen, Canis lupus, commonly known as wolves, preferred salmons over deers if the two preys were available at the same time. The wolves live in the central coastline of British Columbia, and hunt deers for the major food source except in the fall.

The researchers suggested the reason for this salmon eating behaviors using the research done by Szepanski et al.; this behavior appeared as availability of deers became lower in shore side rather than in islands. Darimont, Paquet et al. hypothesized the salmon eating behavior depends on availability of the preferred food sources.

Unfortunately, the method of salmon catching is not observed. It is not found out whether wolves eat leftovers from what bears had, or catch in a group. But the researchers suggested that this study may help explaining the cause of declining numbers of salmons observed over years.

Posted by: Yi, Jeongsang (6)


At 7:01 PM, Blogger PWH said...

I wonder if this is because it requires less energy for the wolf to hunt the salmon rather then the deer. Or maybe salmon just taste better:)

At 7:05 PM, Blogger PWH said...

I wonder if this is because it requires less energy for the wolf to hunt the salmon rather then the deer. Or maybe salmon just taste better:)

Jennifer Smith (6)

At 8:41 PM, Anonymous Anonymous said...

Interesting. I'm curious as to whether they just eat the salmon in the fall because they are plentiful and because each fish takes less energy to catch, and they can catch a fish on their own, rather than in a pack. You mentioned that the researchers believed this may be the reason the fish are declining, but did they mention whether or not they have been doing this for hundreds of years or longer than the study. If this was typical behavior of them, why would they all of a sudden decline. Maybe it's part of the reason. Interesting.

Katie Cole

At 9:57 AM, Blogger PWH said...

This really surprised me. I had no idea that wolves even ate salmon. I wonder why they prefer to eat salmon over deer, is it because there are more salmon so it is any easy catch? Also, I am assuming that they probably have to eat more salmon than they would deer so all in all wouldn't it even out to spending around the same amount of time to catch either of them?

-Tara Quist

At 5:03 PM, Anonymous Anonymous said...

I think the salmon would be full of protein, fats and omega-3 which might be good to stock up on before the winter. I think it would be interesting to look at the interactions between the bears and the wolves. As both predators have to go to the same stream or river to catch the salmon, they are bound to confront each other and maybe even fight for the resource. I also wonder about how the wolves catch the salmon, if they just go at it independently or work in a pack to somehow catch the fish. Are salmon a main part of a bears diet? If it is I would think the bears would be more defensive about their food then the wolves would be, as the wolves still have deer to eat. I, personally, would much rather eat salmon then deer.

Rachel Carboni

At 10:42 PM, Anonymous Anonymous said...

I wonder why salmon? Do the wolves hunt salmon in their packs like deer? Or is it more individually based. Maybe consuming one salmon entirely to themselves is more nutritious than sharing a deer carcus with the pack

Mia DiFabbio

At 10:42 PM, Blogger PWH said...

I wonder what it is that drives animals to specific food. Like as humans we are attracted to specific food by sight, taste, and/or smell. I find it funny that wolves have a preference for these two specific sources of food. Like dogs seem to just eat whatever they can find that has an odor to it. So, this article has me wondering as to what it is exactly about deer and salmon that they attract wolves? Can they recognize that they ate it before and it tasted good?

Chantal Gomes

At 2:37 PM, Anonymous Anonymous said...

It seems like it would take a lot of wolves to cause the salmon numbers to decline. Are wolf populations doing that well? The only case studies I ever hear don't seem to indicate they are doing quite that well. Finding out how the wolves predate the salmon may in-turn allow us to see what if any changes are occurring in the pack's social behaviors.

Allan Eldridge

At 2:43 PM, Anonymous Anonymous said...

Interesting that wolves would hunt salmon. It is another food source to them that is readily available in certain parts of the year. Are they one of the larger causes of the decline of the salmon population? I don't think it would, global warming seems to be the bigger cause of the salmon population. Looks like there is gonna be a bigger competiton for salmon.

Duy Nguyen

At 4:31 PM, Anonymous Anonymous said...

Very interesting article. It is kind of bizzare because I thought that wolves are normally not associated with fish consuming. So the wolf's preference is dependent on the salmon's availability? So they actually prefer salmon over deer? Is salmon more beneficial (i.e. nutritious) than deer meat? How has this developed? When did the wolf realize that salmon is better?

Hanbing Guo

At 5:30 PM, Anonymous Anonymous said...

Very interesting. I wonder wha the motives are for the wolves perfering salmon. I wonder if this preferance holds true for all species of wolves? Maybe it is cleaner to eat salmon than deer too. They might beable to eat all the meat easier.

Alex Pavidapha

At 5:35 PM, Anonymous Anonymous said...

Why does this imply that wolves prefer salmon? It is stated that the amount of deer that are eaten doesn't change so why should the change in salmon eating constitute a preference for salmon? On a side note, the plural form of deer is deer and the plural form of salmon is salmon.

Alex Jackson

At 6:00 PM, Blogger PWH said...

I know wolves are pack hunters and use tactics to take down their prey, mainly deer. Im curious if they hunt the salmon in packs or they just do it individually. Additionally I would assume that salmon take much less energy to catch then a 200-300 lb deer. At the same time however a salmon can probably only feed 1 wolf as oppose to the whole pack like a deer has the capability to do. I wonder why they make that transition across seasons.

Patrick Salome

At 6:35 PM, Anonymous Anonymous said...

This is really interesting... Maybe one wolf had salmon once and it was a much better nutricious supplement then deer... and the other wolfes then learned that eating salmon increased their chance of survival... Or maybe wolfes realized that there was a high number of salmon in their environment and decided that it was more advantageous to change their diets from deer to salmon.

Brena Sena

At 6:53 PM, Blogger Dan said...

Are there any specific reason that makes wolves have such a liking to the salmon during the fall or is it simply just another food source.

~Dan Hong

At 7:54 PM, Blogger PWH said...

This comment has been removed by the author.

At 7:56 PM, Blogger PWH said...

Is there any specific nutritional reason the wolves are doing this in the fall? Are deer harder to come by in the fall? I would never have thought that wolves actually hunt salmon. It would be interesting to witness wolves in the act of hunting the fish.

Rob Lubenow

At 8:03 PM, Blogger PWH said...

Do you know how the wolves hunted the salmon? Is their hunting mechanism similar to bears? Do you think that their preference for fish has to do with a lower risk in injury? I mean, there less of achance of getting hurt hunting salmon than hunting a deer? Do you know if they would do this in groups (packs) or alone? And do you think that the salmon could have been shared by the wolves and therefore, salmon remains ended up in their feces? Also, was the study only done with wolves on the British columbia coastline? Or were wolves in other areas studied as well, sort of as a control? Thanks for your post.

-Amanda Sceusa

At 8:27 PM, Anonymous Anonymous said...

I'm surprised that wolves would prefer salmons over deers, since there are more meat in deers. Is the reason because capturing deers require more energy?

- David Huynh

At 8:58 PM, Anonymous Anonymous said...

Is it easier to catch salmon? If so, this would be less energy because they wouldn't have to run around and chase the deer (and even split the catch with the pack). Even better would be if the salmon were more abundant then. Do you think they stay with their packs when they do this? This seems like a task for only one to do. Maybe the fish have more energy in them, and maybe they taste better (if the wolves have a good sense of taste that is)? This is a really good find. Good job!

-Alyson Paige

At 10:32 PM, Anonymous Anonymous said...

This is surprising because I've never heard of wolves eating fish. Then again, bears eat salmon and fish often and that is a well known fact so why couldn't other large animals hunt fish? They are very good for people and animals alike so it is a nutritional benefit to add salmon to ones diet. I wonder if they enjoy salmon more or if it is strictly because of energy. Also, what other animals commonly feed on salmon? That would be interesting to learn.

-Julie Riley

At 10:37 PM, Blogger PWH said...

I would think that the salmon would provide such nutrients at fish oil and fatty acids, such things that deer could not provide. I would think that wolves hunting salmon would be incredible inefficient because that have to use only their jaws to catch the salmon and not their paws so I find it hard to believe that wolves are a contributing factor in the decline in salmon populations. I am interested in their hunting style, I know that wolves rely on packs to take down game, did they use pack mentality to herd the salmon into shallower water?

-Joe Alonzo

At 11:59 PM, Anonymous Anonymous said...

It is easy to assume that a wolf would rather eat a fish over a deer for reasons such as it being more available, or easier to find. However, could it be that the vitamins in it are more fitting to protect it and help it survive over the winter?

Ahmed Sandakli

At 12:16 AM, Blogger PWH said...

very interesting..who would of thought wolves preferred salmon over deer. I wonder if it has anything to do with the fact that salmon is only available during the fall season whereas they eat deer for the rest of the year. It sort of could explain why salmon populations are decreasing as a result of only being available during one season.

-Joanne Philippeaux

At 2:11 PM, Blogger PWH said...

Wolves eat salmon. It is interesting. I thought wolves would prefer to eat meats not fish. Do you know why wolves eat salmon in fall? Is it for nutrition balance or not? I just wonder what makes them to choose a salmon than deer. This is very interesting article.

So Jin Lee

At 3:31 PM, Anonymous Anonymous said...

I wonder how the wolf physically hunts the salmon. When we fish we use either bait and a hook (or a spear that was used in the earlier days) or a net, all of which wolves physically can't make or use. On top of that, for a wolf to hunt a salmon using his mouth alone he must be able to see effectively through the water and have the co-ordination to bring his mouth to the right place, all while maintaining his stability in the water. This brings me to question how much the fact that the wolves were somehow offered the two foods affects the results.

Noam Pelleg


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