Orca shark interactions

[theropod]

Yes, FKW are lower in trophic systems than GWS since they target mostly fairly smaller preys.

I said:

I already wrote, the fish prey of false killer whales broadly overlaps the mammalian prey of adult great white sharks in terms of size, and they prey on dolphins too, just like great whites.

The cookiecutter is a parasite even targetring adult baleen whales, not comparable at all.

That’s the point, it is not comparable at all, and still according to your logic it’s higher in the trophic system, since it frequently targets mammals.

I already wrote too that Mako sharks (and Longimanus) also target on these fast big fishes and on dolphins.

Yes, occasionally, but no sperm or humpback whales.

C. leucas and G. cuvier too target dolphins. Does that means these sharks are at the same trophic systems than C. carcharias ? I guess not.

G. cuvier certainly overlaps, but it appears to be smaller on average, and save for one not really that relevant account of semi-scavenging on a dying blue whale I’m not aware of it taking prey as large as False killer whales or Great whites do.

As regards mako shark predation on dolphins, here you have an interesting quote:

heithaus 2001 said:

Suspected predators on cetaceans include the short®n
mako shark Isurus oxyrinchus, Paci®c sleeper shark
Somniosus paci®cus and Greenland (sleeper) shark
Somniosus microcephalus (Table 2). An adult common
dolphin Delphinus delphis was found stranded alive with
fresh mako shark bite wounds, but the dolphin was
highly parasitized by liver ̄ukes and had trematodes in
its brain (Ridgway & Dailey, 1972). As this dolphin may
have been incapacitated at the time of the attack this
cannot be treated as a de®nitive predation event.

from: www.researchgate.net/publication/228601732_Predatorprey_and_competitive_interactions_between_sharks_%28order_Selachii%29_and_dolphins_%28suborder_Odontoceti%29_a_review

If this is only so vaguely hinted in the literature it is not a common event at all.

I've presented a reference from Compagno quite specific, I'd ask to presen another reference which explains clearly the contrary of what is claimed here.

You haven’t even given the reference, please post it. Compagno has published more than a single study on sharks in his life.

elosha11: The thread title is "orca shark interactions", isn’t it? Those were all actual orca-shark-interactions, all of them quite one-sided obviously (but any interaction between an adult Orcinus and a shark is).
The great white shark in the first account was estimated at 3-4m long, and the female orca that killed it at 4.7-5.3m, both were smallish individuals.

Yes but again, you are talking about large prey items FKW normally take in a group attack, not as individual predators. Again, since this thread is primarily concerned with comparing orcas and pseudo orcas' individual predatory capabilities, we should not penalize the solitary great white by comparing their prey selection to the large prey FKW normally take in a group attack.

Well, that was new to me, I thought this thread was actually concerned with their interactions. I have to admit that discussing the respective diets of fkws and gws was off-topic though.

Also, I don’t think dolphins or tuna are killed by several Pseudorca at a time (perhaps chased, I’ll give you that). That’s the prey size that would easily be killed and devoured by a single predator this size, or would you claim that FKWs lack the anatomical capability of killing smaller dolphins?
That odontocetes take advantage of their social lifestyle is one thing, but it doesn’t imply that the individual is not formidable and unable to kill prey larger than small fish on its own–animals only adapted to kill small fish/squid (e.g. pilot whales) don’t kill larger prey at all, whether in a group or not.
On the other hand, individual lions for example are no less formidable than other individual predators, you can’t just judge their capabilities by dividing their prey size by the size of the pride.

Does this mean that I think a great white is a equal one on one fighter/predator to an orca? Absolutely not, because even at maximum sizes, the orca will be significantly larger and almost always surrounded by pod mates. But is a large great white, or even a very large tiger or mako shark a very dangerous prey item for a single or even multiple orcas? Yes because even attacking as a group, a large shark could do some serious damage to an orca. So while I find these videos of orcas killing sharks impressive and clear evidence of their status as apex predator, I have no problem believing that a large solitary orca and a large great white would each keep a respectful distance from the other - for obvious reasons.

I have no problem with that either, it likely happens most of the time. But as I understood it what you were suggesting earlier is that at the same size the great white shark was a superior fighter. Frankly, I find that statement completely lacks evidence.

So even though individual orcas are certainly on the whole larger and more powerful than the great white, there isn't really all that much difference in the size of the prey each can individually take down. Both a solitary orca and a great white can individually prey on adult elephant seals for instance. This is a prey item that an individual false killer whale would almost certainly never attack.

Firstly, I think accounts of orcas preying on elephant seals (especially adult bulls) are a lot more abundant and less obscure than those of great whites:
two nice examples:
www.youtube.com/watch?v=UbJn-0cI3Vs
www.youtube.com/watch?v=o2XlS8bkltU
By contrast, the only footage of great whites involves seal pubs. Also note how some most of the elephant seals taken by orcas are probably southern elephant seals, while the only mention of great whites actually taking adults is about northern ones. So no, individual orcas and great whites don’t appear to have the same potential prey size based on current data.

Secondly, determining maximum size of prey taken by gregerious animals on their own is always tricky. Wolves and lions for example have been recorded being able to subdue most of the animals they usually hunt in packs/prides on their own (e.g. muskox, bison, buffalo, giraffe), but of coruse they do it much more commonly if they have numbers on their sides.
Thirdly, this isn’t so important for a confrontation between predators.

And false killer whales are mostly pelagic, so no surprise that they won’t attack elephant seals.

A great white is both designed and inclined to take larger prey items - on the whole - than a solitary FKW would be.

I wouldn’t equate brontophagous adaptions to adaptions that would be of great value in a confrontation between two similar-sized opponents. Ironically I often get called a fanboy by someone when I only suggest animals with slicing teeth to be just as formidable as those with crushing teeth–certain people consider the latter "more direct and brutal", at least in some scenarios.
A solitary FKW may be less inclined to attack large animals for psychological reasons, that doesn’t mean it doesn’t have similar physical capabilities to a great white shark. It is similar in size, highly athletic and has a formidable killing apparatus.

The evidence and other support I have to suggest, (notice I didn't say prove, nor have I ever said prove) that great whites or other large sharks occasionally prey on FKW is (1) a 3.8 meter female bitten by a large shark likely contributing to its stranding (2) an adult FKW with recently healed large shark bite around its middle (often an attack point) likely bitten by great white or tiger (2) a respected research paper re FKW's suggesting large sharks occasionally feed on FKW's (4) a second FKW research source again stating large sharks likely prey on FKW on occasion (found yesterday, will try to find again and post), (5) research from Compagno indicating that great whites tackle larger prey more frequently than FKW) and (6) quite likely evidence of great white predation on pilot whales, a dolphin that may even be larger than the FKW, but not as formidable. (Still not entirely a bad proxy).

Imo a pretty bad proxy. An easily apparent analogy for this would be to claim a Suchomimus was a good proxy for an Acrocanthosaurus, just because both are similar in size. One is a predator of large animals, the other of small animals and fish, and this is reflected drastically by their jaws. So that some creature would be able top prey on/hold their own against one doesn’t imply the same about the other, because size matters, but weaponery too.

What do these bite marks indicate? That the FKW had a confrontation with a shark, and that the shark didn’t kill it during that confrontation, no more, no less. Also, if the healed bite mark is supposedly a sign of a predatory attack, why wasn’t the bite mark on the tail, or at least the ventral side of the animal, where a shark would be likely to strike at a large prey item? And is a bite wound without fatal consequences evidence for a predator-prey relationship? If so, would you call what squid and cookiecutter sharks do "predation on large whales"?

There are several possibilities here, this involves a predatory attempt gone very wrong from either party (plausibly from a shark significantly larger than the 3.8m Pseudorca, or from a pod of Pseudorca wherein that one got injured), a case of mistaken identity of the seeming prey item, or a non-predatory confrontation of some sort. I don’t think we can decide which is the most likely, or what it implies for relationship between the two on species level.

This doesn't mean that I think a false killer whale would have no chance against a comparably size great white. I think it's quite possible that FKW have sometimes prevailed in such encounters, either individually or as a pod. But on balance, the evidence suggest that more likely than not it is the shark that is usually the aggressor in one on one predatory encounters. And yes such interaction are probably very rare for many reasons, not the least of which the animals are somewhat evenly matched and dangerous to each other. In fact, FKW may even displace large sharks on occasion since they operate in large pods.

I think this evidence is an artifact of the false killer whales’ tendency towards stranding…

Look we may just have to agree to disagree here.

I guess so. Obviously we have different views on what’s actual evidence, and we also seem to have different views on what the thread subject is.

[creature386]

Oct 5, 2014 11:02:49 GMT 5 elosha11 said:

Oct 5, 2014 0:33:17 GMT 5 creature386 said:

What I said was simply that it is hard to imagine that the gap in prey size between a KW and a GWS is smaller than in FKW vs GWS. They may not hunt really large whales commonly, but they attack relatively large whales a lot more common than great whites so. Accounts of killer whales preying on false killer whales are a lot better documented than predation on false killer whales by great white sharks.

Yes but also keep in mind for purposes of this thread, that we should be comparing the morphological features of an individual orca to an individual great white. An individual orca would almost certainly never take on an adult sizeable humpback or sperm whale; orca pods take on such prey. So even though individual orcas are certainly on the whole larger and more powerful than the great white, there isn't really all that much difference in the size of the prey each can individually take down. Both a solitary orca and a great white can individually prey on adult elephant seals for instance. This is a prey item that an individual false killer whale would almost certainly never attack. I think, that at least in part that's what Compagno references. A great white is both designed and inclined to take larger prey items - on the whole - than a solitary FKW would be.

I know that a sperm or humpback whale is out of the range of a single orca, but there are enough prey items that are in the range of singe orcas, but out of the range of great whites. Because you mentioned elephant seals:

Southern elephant seals have only one major predator, the killer whale (Voisin, 1976; Carrick and Ingham, 1962; Ling and Bryden, 1981; Lopez and Lopez, 1985).

books.google.at/books?id=2My8M5tL-KIC&lpg=PP1&hl=de&pg=PA204#v=onepage&q&f=false
Great white sharks prey on the smaller Northern elephant seals commonly, but not on the larger Southern elephant seals. It is the reserve in killer whales:

swfsc.noaa.gov/uploadedFiles/Divisions/PRD/Publications/Jeffersonetal.1991(8).pdf
I know that they often attack even medium sized mammals in larger packs, but I believe this is for chasing purposes (this may explain why groups for smaller prey are larger than the ones for large prey). An orca would have no problems killing a Southern elephant seal. I admit that a great white shark could also kill one, but does so rarely, so I think we can say it is out of its prey range.

[theropod]

That’s what I meant too. With this type of prey item the pod may play a role in helping to chase the prey item, but a single individual will do the killing.

[creature386]

I admit that I repeated a lot, but I at least brought up some new material. Oh, and for the ones who are interested in support for my "this may explain why groups for smaller prey are larger than the ones for large prey" statement:

[theropod]

"Although not all attacks on large whales by large groups of Killer Whales (over five animals) were seen to be successful, most instances in which a kill or feeding took place involved relatively large groups of predators. There is some evidence, however (much of it from the whaling literature), to suggest that singles or groups of two or three Killer Whales can, at times, overcome and kill large baleen whales (Eschricht, 1866; Bullen, 1898; D.L. Kelly, unpubl.; Reeves & Mitchell, 1988). It is possible, however, that larger Killer Whale groups may have split up in some of these instances to feed on several whales." Jefferson et al. 1991, p. 159

Reference:
swfsc.noaa.gov/uploadedFiles/Divisions/PRD/Publications/Jeffersonetal.1991%288%29.pdf

[elosha11]

Wow theropod, you've replied to like four or five different posts of mine and Grey in one single post. I will answer substantively and comment on the other posts by you and creature386 hopefully later today. Got lots of work to do, so might be late tonight or tomorrow. Suffice it to say though, there is definitely some misinterpretation of some of the points I'm trying to make and the "subject" or "purpose" of this thread. But will explain in more detail later...

[creature386]

Oct 5, 2014 18:40:20 GMT 5 theropod said:

"Although not all attacks on large whales by large groups of Killer Whales (over five animals) were seen to be successful, most instances in which a kill or feeding took place involved relatively large groups of predators. There is some evidence, however (much of it from the whaling literature), to suggest that singles or groups of two or three Killer Whales can, at times, overcome and kill large baleen whales (Eschricht, 1866; Bullen, 1898; D.L. Kelly, unpubl.; Reeves & Mitchell, 1988). It is possible, however, that larger Killer Whale groups may have split up in some of these instances to feed on several whales." Jefferson et al. 1991, p. 159

Reference:
swfsc.noaa.gov/uploadedFiles/Divisions/PRD/Publications/Jeffersonetal.1991%288%29.pdf

I am thinking if we should create a thread for this because we have some data on it.

But I think posting it in this debate is no problem because it is not off topic.

[theropod]

It does sort of contradict the thread title ("orca shark interactions"), but since nobody seems to have a problem with it, I think it would make sense to extend the debate to an eco(morpho)logical comparison.

[creature386]

Yeah, but comparing the prey of sharks and orcas can also be useful for looking at how they interact. Interactions don't have to be predation on each other.

[theropod]

It is relevant to their ecology and thus indirectly also to how they interact, yes.

[theropod]

Here’s one of the references from the previous quote I posted:

Eschricht 1866 said:

Captain Holböll’s own account of the manner of living of the killers, is to the following effect
" In the year 1827, I was myself an eye-witness of a great slaughter performed by these
rapacious animals. A shoal of Belugas had been pursued by these blood-thirsty animals into a
bay in the neighbourhood of Godhavn, and were there literally torn to pieces by them. Many
more of the Belugas were killed than eaten, so that the Greenlanders besides their own booty,
got a good share of that of the kilers. In the year 1830, a large krepokak (Megaptera longimana)
was overpowered by an Orca, in the neighbourhood of Narparsok, according to the statements of
the Greenlanders, and torn to pieces after it was dead. Almost fifteen barrels of the blubber
floating about at the place where the struggle had taken place, fell to the share ofthe Greenlanders.
It is principally the blubber that is the most coveted food of the killers, notthe tongue as I have seen stated in several places.
In this krepokak especially, the tongue wasfound untouched, and was afterwards flensed by the Greenlanders."

I think it’s pretty save to say that individual orcas can go after larger prey than individual great white sharks.

Btw about Pseudorca:
Baird et al. (1989) report a beached individual 4.62m in TL and 59.5cm in skull lenght.
Pardo et al. (2010) describe an individual with a skull lenght of 61.8cm, the total lenght of the skeleton being 4.37m, but Eschricht (1866, p. 184) describes a small orca as having been over 8% longer than its skeleton when fresh, so this one may have been about 4.73m long (which is more consistent with the first report) in life.

---

References:
Baird, R. W.; Langelier, K. M.; Stacey, P. J.: First Records of False Killer Whales, Pseudorca crassidens, in Canada. Canadian Field Naturalist, Vol. 103 (1989); 3; pp. 368-371
Eschricht, D. F.: On the Species of the Genus Orca inhabiting the Northern Seas. In: Flower, W. H.: Recent Memoirs on the Cetacea. London (1866); pp. 151-188
Pardo, M. A.; Jiménez-Pinedo, C.; Palacios, D. M.: The false killer whale (Pseudorca crassidens) in the southwestern Caribbean: first stranding record in Colombian waters. Latin American Journal of aquatic Mammals, Vol. 7 (2009); 1-2; pp. 63-67

[Grey]

That’s the point, it is not comparable at all, and still according to your logic it’s higher in the trophic system, since it frequently targets mammals.

No, the cookiecutter has a parasitic lifestyle nd is itself preyed by predators so it just does not operate at the same tropic level.

But by your logic, the mako, longimanus and other larger sharks operate at the same level than GWS.

Yes, occasionally, but no sperm or humpback whales.

I don't think that preying on dolphins and big fishes is just occasionnal for these sharks. Galeocerdo individuals are regularly caught with one or two dolphins in the stomach. Howevere, there is only one reported case of Megaptera flesh found in the stomach of a FKW, so that's definitely not a regular basis prey.

Regarding sperm whales, weren't the FKW just flesh grazing ?


Regarding Mako and its ocurences of predation on dolphin, this paper appears outdated :

www.youtube.com/watch?v=xPG4AkUC3WU&spfreload=1
www.youtube.com/watch?v=8UB1aHaU0Lw&spfreload=1

Mako kills and eat dolphins regularly hunting athletic warm-blooded species is its speciality, not an opportunity.

You haven’t even given the reference, please post it. Compagno has published more than a single study on sharks in his life.

Compagno 1990 Alternative life-history in cartilaginous fishes in time and space.

I think it’s pretty save to say that individual orcas can go after larger prey than individual great white sharks.

So a very old account (1866) of an event never observed again since is convincing enough for you but the indication of different place in trophic systems for FKW and GWS by Leonard Compagno is not convinving enough ?

I stop here the discussion for now, I accept the debate but you start losing your objectivity here. I don't want this becomes conflictual. I let others discuss this.

[elosha11]

I am going to respond in greater detail, but I couldn't resist addressing theropod's last comment and some related proceeding ones. Theropod, I will simply note here that you are misconstruing what I said about great whites and orcas' common prey selection. I never said that orcas cannot go after larger prey even as a solitary individual. Of course they can, they are on a completely different size strata from the great white. However, they do share a significant overlap with great whites on the large prey they select, such as large northern elephant seals. These are a size of animals a single or pod of FKW has never been documented to attack. Also theropod is incorrect that the only evidence shows that great white attack northern elephant seal pups; it's pretty common knowledge that they will attack and consume juveniles and adults, including bulls. On carnivora, there is a research article (and I'll try to find it at some point) describing in detail a large great white approaching, ambushing, and consuming a bull elephant seal. Likewise, on the recent Shark Week documentary detailing predatory attacks on elephant seals on Guadalupe Island, a large bull elephant seal is shown with a gaping and very serious (but apparently not life threatening) injury from a great white. The whole show is documenting very large great whites (three highlighted sharks are about 15, 18, and 20+ feet respectively) stalking and hunting elephant seals.

Moreover in considering the general comparison of great white v. FKW prey selection, it's noteworthy that despite the relative scarcity of great whites compared to the number of FKW's it simply much more common to find evidence of great white attack on large prey, whether on fellow sharks, tuna, large pinnipeds, cetaceans/small whales. And while FKW are not as well studied as orcas, there have been some significant and long going studies of FKW populations, some of which I have already cited earlier in the thread. None of them note evidence of regular targeting of large prey. FKW's primary diet is medium sized fish, with occasional targeting of larger prey such as dolphins (virtually always as a pod attack). That's why researchers like Campagno can state without qualification that great whites generally and more often take larger prey than FKW's. (BTW theropod, you've been asking Grey to produce the whole paper, but I think he got it from carnivora GW v. FKW thread. Another poster posted the exact same excerpt and did not cite his source for how he got it).

So the point I'm making - and which is being misinterpreted - is not that single orcas can't take larger prey and more often than great whites - it's that orcas and great white share far more common large prey overlap than does the FKW. In other words, the documented evidence more clearly suggests that single orcas and single great whites take large, and potentially more dangerous prey on a more regular basis that a solitary or perhaps even multiple FKW. You can dispute that if you wish, but the evidence and the research is pretty ironclad in my opinion.

[Grey]

Oct 5, 2014 18:08:32 GMT 5 creature386 said:

I admit that I repeated a lot, but I at least brought up some new material. Oh, and for the ones who are interested in support for my "this may explain why groups for smaller prey are larger than the ones for large prey" statement:

This is strange since the most famous account of attak on a blue whale involved 29 orcas individuals.

[theropod]

But by your logic, the mako, longimanus and other larger sharks operate at the same level than GWS.

No, that they show marginal overlap in terms of diet doesn’t mean that they operate on the same trophic level, especially if the animal is completely different in terms of size. But they have to be demonstrably different both in their relation to prey and each other in order for one to be higher.

I don't think that preying on dolphins and big fishes is just occasionnal for these sharks. Galeocerdo individuals are regularly caught with one or two dolphins in the stomach.

Source for this claim…?

Howevere, there is only one reported case of Megaptera flesh found in the stomach of a FKW, so that's definitely not a regular basis prey.

No, it is not, I never claimed it was. The largest prey items taken by great white sharks are also not a regular prey item.

Regarding sperm whales, weren't the FKW just flesh grazing ?

Why "just"?

Regarding Mako and its ocurences of predation on dolphin, this paper appears outdated :

www.youtube.com/watch?v=xPG4AkUC3WU&spfreload=1
www.youtube.com/watch?v=8UB1aHaU0Lw&spfreload=1

Mako kills and eat dolphins regularly hunting athletic warm-blooded species is its speciality, not an opportunity.

Yes, these accounts are newer. That doesn’t suddenly make it common though.

Compagno 1990 Alternative life-history in cartilaginous fishes in time and space.

Thank you! Now, was that so difficult?

So a very old account (1866) of an event never observed again since is convincing enough for you but the indication of different place in trophic systems for FKW and GWS by Leonard Compagno is not convinving enough ?

Who sais it was never observed again? The quote I posted contains 4 references, this one was just the first one I’ve found.
Also this was a specific account, your quote refers to these animal’s general ecology without giving actual points in support of the hypothesis.

I stop here the discussion for now, I accept the debate but you start losing your objectivity here. I don't want this becomes conflictual. I let others discuss this.

Have fun. As always, I’m not the one losing my objectivity, otherwise why am I the one demanding evidence for the favouring of one side?