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Post by prehistorican on Jul 20, 2018 15:36:01 GMT 5
Do modern odontocetes do depth charges like sharks? I wouldn’t be all that surprised if the shark did an attack like that on the Livyatan. I doubt the extreme agility compared to sharks or speed as seen with bottlenose dolphins and white sharks. Especially claims that the whale had some extreme agility that it could turn to face its attacker no matter what angle it is being attacked from. Also the fwk and white shark comparison. This is what one aquarium website said “Researchers believe that false killer whales can grow to 57.5 years of age for males and 62.5 years for females. This is based on counting the rings on the teeth of dead animals. They have been observed reaching speeds of 5.5-11 kilometres/hour (3.4-6.8 miles/hour) and up to 18 km/hour (11 m/hour)”. White Sharks have been observed to go to 40kmh, but just in case I think it is extremely possible for fkw to exceed 30kmh.
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Post by sam1 on Jul 20, 2018 17:01:27 GMT 5
How about you learn a ton more about whales. You skipped the info about exactly the things you ask about.  Some key takeaways: The whales maneuver extensively at the peak of a burst, employing rolling, pitch and yaw change of position. The maximum roll and yaw figures are quite impressive, 65 and 86 degrees per second, respectively. Additionally, they are able to deccelarate actively, and do so after each inflectional burst. "Deceleration rates during bursts were substantially larger than those recorded during glides (deceleration during burst: -0.55 t 0.5.1 m s'2, n : 21; deceleration during horizontal glide: 0.026 t 0.0.15 m s'2, n : 34; GLMIMI, X2, : 1 05 . 7 , p < O . 000 .1 ) , indicating that deceleration during bursts was not passively attained. Rapid decelerations coincided with larger changes in pitch and heading (GLMM pitch: )(21 : .15.8, p < 0.000.1; heading: X21 : 25.9, p < 0.0001; swim speed: X21 : 65.5, p < 0.0001). Such changes in heading or pitch are expected during horizontal and vertical turns." In other words, my description of Livyatan's charge, roll, and subsequent deceleration maneuvers were exactly based on these scientific observations of sperm whales. |
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Post by sam1 on Jul 20, 2018 17:09:23 GMT 5
Also, there's nothing super about your supposed "super maneuvering" while being stationary.
The sperm whale is more than able to rotate in place in any direction quickly enough to keep up with a shark that actually has to swim around it in circles.
It's pretty basic physics. Go watch some videos of divers interacting with sperm whales. They can do a 360° faar quicker than a giant shark would be able to, swimming in a circle around it.
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Post by prehistorican on Jul 20, 2018 20:10:31 GMT 5
Any evidence the sperm whale was SIGNIFICANTLY faster at burst speed? I doubt that. How do we know the agility of a giant shark at burst speed for certain? And no, I don't need to listen to you and go learn a ton more about whales. I have much more things to do than spend hours reading up on cetaceans or really any animals.
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Post by sam1 on Jul 21, 2018 2:30:47 GMT 5
Okay. As long as you know all about Megalodon. As for the significantly faster burst speed, you're making me repeat myself. It was a hypothetical assumption to illustrate a point to theropod. |
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Post by theropod on Jul 21, 2018 2:54:52 GMT 5
prehistorican: Visser et al. 2010 cite Pseudorca to have been clocked at 8ms⁻¹ (29km/h), but maximum speed is presumed unknown. So yeah, not much info there ( Pseudorca is notoriously poorly studied), but they are probably pretty fast, and definitely comparable to similar-sized sharks in terms of athleticism. I guess we can’t reasonably assume aquarium websites to provide comprehensive information on such matters. By "depth charge" you mean a high speed attack from below? Visser et al. also documented predation by Orcinus on Pseudorca, with instances of individual orcas ramming Pseudorca individuals from below. One was on a Pseudorca that was already breaching out of the water, catching up with it and propelling it 8.5-12.5m into the air. The orca too continued on its trajectory to the point of completely clearing the surface. So its hard to say how fast the orca was when attacking, although the Pseudorca must have been pushed upwards on the order of 13m/s given its observed shift in position, which corresponds well with an orca ramming into it at high speed. Visser, I. N., J. Zaeschmar, J. Halliday, A. Abraham, P. Ball, R. Bradley, S. Daly, T. Hatwell, T. Johnson, and W. Johnson. 2010: First Record of Predation on False Killer Whales (Pseudorca crassidens) by Killer Whales (Orcinus orca). Aquatic Mammals 36.
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Post by prehistorican on Jul 21, 2018 5:44:42 GMT 5
prehistorican : Visser et al. 2010 cite Pseudorca to have been clocked at 8ms⁻¹ (29km/h), but maximum speed is presumed unknown. So yeah, not much info there ( Pseudorca is notoriously poorly studied), but they are probably pretty fast, and definitely comparable to similar-sized sharks in terms of athleticism. I guess we can’t reasonably assume aquarium websites to provide comprehensive information on such matters. By "depth charge" you mean a high speed attack from below? Visser et al. also documented predation by Orcinus on Pseudorca, with instances of individual orcas ramming Pseudorca individuals from below. One was on a Pseudorca that was already breaching out of the water, catching up with it and propelling it 8.5-12.5m into the air. The orca too continued on its trajectory to the point of completely clearing the surface. So its hard to say how fast the orca was when attacking, although the Pseudorca must have been accellerated upwards on the order of 15km/h given its observed shift in position. Visser, I. N., J. Zaeschmar, J. Halliday, A. Abraham, P. Ball, R. Bradley, S. Daly, T. Hatwell, T. Johnson, and W. Johnson. 2010: First Record of Predation on False Killer Whales (Pseudorca crassidens) by Killer Whales (Orcinus orca). Aquatic Mammals 36.
That's cool, do they charge it at high speed and clamp down their jaws into a prey item simultaneously though such as a shark depth charge. Do cetaceans do it often? |
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Post by Infinity Blade on Jul 21, 2018 5:59:48 GMT 5
The yaw figure for the sperm whale is quite impressive and...actually about what I expected. I mean, I knew that even though whales undulate their tails in the dorsoventral plane they could still turn laterally quite quickly (I saw this in a video with a captive orca once).
Theropod do you still think the shark would most likely turn faster in yaw (or that mobility is comparable between the two)? I would indeed expect that intuitively, but I'm open minded to that intuition being wrong.
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Post by prehistorican on Jul 21, 2018 8:42:33 GMT 5
I don’t know that much for sure. But it seems for their size white sharks are at least decently agile and making moderate fast turns.0:32-0:34 is probably an slightly fast and tight turn. youtu.be/QK3jtOmwHUQ |
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Post by theropod on Jul 21, 2018 17:11:46 GMT 5
prehistorican: I’m not very familiar with orca hunting behaviour on smaller prey in a pelagic setting (as opposed to close to the shore or pack ice), but I don’t think so. Even with dolphins and seals, it seems they prefer to simply ram their prey to incapacitate it. One tends to see them use their jaws mainly for gripping, e.g. when beaching themselves to pull a seal back into the water or similar situations. In large prey, I think it is avoided simply because they would encounter too much resistance. Having a dentition adapted to puncture and hold, not cut, and ramming into a large cetacean with opened jaws at high speed is probably riskier and less effective than ramming it with the tip of the rostrum or melon. Infinity Blade: That was only based on intuition from me too, no actual data behind it in the first place. Just a default assumption based on the primary planes of movement of the two taxa. Of course whales can also yaw quickly. Additionally, if they couldn’t, they could simply roll and therefore pitch instead. We might never know for sure how they compare, because as I wrote its hard to get a wild, marine animal to swim, accellerate or turn at its fastest and harder still to know whether it did.
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Post by sam1 on Jul 21, 2018 17:52:43 GMT 5
Orcas almost never use their jaws outright, unless the prey if of the largest size and can't be weakened by other means.
Fish are targeted by tail slaps, seals and dolphins by ramming and slapping.
It is simply a more effective and safe method, especially when preying on large seals. Their flexibility, teeth and claws are a risk to the eyes of an attacker. That is why sharks have developed eyeball roll mechanisms. They lack the agility and body control to reliably slap their prey(some species, like the tresher shark, found a way around this via specialized evolution).
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Post by sam1 on Jul 25, 2018 14:33:12 GMT 5
For what it's worth, some footage of whale shark turning to avoid impact, and accidentally ramming into a manta ray.
The slow motion of the collision with manta kind of leaves an impression that this shark couldn't withstand too much force this way.
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Post by sam1 on Jul 25, 2018 14:43:39 GMT 5
P.s. Grey, your analogies with GWS and FKW are good arguments, I agree.
There's not a single record of FKW killing a GWS at parity, although technically they should be capable of doing so.
I'm just not so sure on that "should" part.
Maybe at their size category, ramming isn't effective enough versus the great white. Also, their jaws, while seemingly capable of biting off a pectoral fin of the great white, don't look like they would be able to deliver enough damage prior the prolonged and vigorous trashing of the shark..just my opinion though.
Finally, there's the question of how combative and aggressive the FKW typically are. My impression is that they are, despite of many similarities, rather docile in comparison to orca.
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Post by theropod on Jul 25, 2018 18:17:34 GMT 5
There’s no single record of a GWS killing a FKW either though. The only thing we have is a blog post reporting a damaged fin and "superficial" shark bite marks on a beached 3.8m female that later died in captivity. If this was failed predation by a great white shark (which is a possibility, but not the only one) then that hardly means it must have been a parity engagement, considering a 3.8m FKW would weigh around 450kg or less (based on data in Kasterlein et al. 2000). Cetaceans preyed upon by white sharks are consistently significantly smaller than the attacking shark, and the biggest scientifically recorded odontocete prey of C. carcharias are 3m beaked whales preyed upon by 5m great whites (Long & Lones 1996). So if great whites really do prey on the much more formidable false killer whale, then our default assumption should also be that they only do it with a considerable size advantage, just like orcas preying on great whites. The size difference between a 5m great white and a 3.8m FKW is not dissimilar to that between the 4.7-5.3m Orca and its 3-4m white shark prey observed by Pyle et al. (1999). So while evidence that Carcharodon ever preys on Pseudorca is ambiguous to begin with, that’s still of far more limited use regarding size-parity interactions between macropredaceous odontocetes and lamniforms than has been suggested here, and certainly not evidence that sharks dominate these encounters at parity. Furthermore, if Livyatan’s skull had been proportionally as small as Pseudorca’s, the holotype would have been 22-23m long (Baird et al. 1989, Pardo et al. 2009) and 82-99t in mass (Kasterlein et al. 2000). If we were to consider Livyatan comparable in morphology to Pseudorca, this would not be a parity matchup at all. Pseudorca may reach lengths similar to great white sharks’, but a Livyatan the same length would be both far more massive and have much bigger jaws than a Pseudorca, and, unlike Pseudorca today, it was probably an apex predator mostly feeding on large mammalian prey, not mostly specialized on large pelagic fish and squid. Baird, R. W., K. M. Langelier, and P. J. Stacey. 1989: First records of false killer whales, Pseudorca crassidens, in Canada. Canadian field-naturalist. Ottawa ON 103:368–371.
Kastelein, R. A., J. Mosterd, N. M. Schooneman, and P. R. Wiepkema. 2000: Food consumption, growth, body dimensions, and respiration rates of captive false killer whales (Pseudorca crassidens). Aquatic Mammals 26:33–44.
Long, D. J., and R. E. Jones. 1996: White shark predation and scavenging on cetaceans in the eastern North Pacific Ocean. Great white sharks: the biology of Carcharodon carcharias:293–307.
Pardo, M. A., C. Jiménez-Pinedo, and D. M. Palacios. 2009: The false killer whale (Pseudorca crassidens) in the southwestern Caribbean: first stranding record in Colombian waters. Latin American Journal of Aquatic Mammals 7:63–67.
Pyle, P., M. J. Schramm, C. Keiper, and S. D. Anderson. 1999: Predation on a white shark (Carcharodon carcharias) by a killer whale (Orcinus orca) and a possible case of competitive displacement. Marine Mammal Science 15:563–568.
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Post by prehistorican on Jul 25, 2018 18:39:26 GMT 5
That may not even be a great white shark. Even dusky sharks have been known to attack and kill marine mammals. The wounds they inflict are quite superficial but because they are mainly pisciviorous. The authors hinted that the duskies had a relatively small bite width and incapable dentition to directly kill large marine mammals. (Yet the 15 sharks at 1400kgs total killed the 1600kg calf anyway). If even dusky sharks attempt to tackle Marine mammals, then really most large sharks can maybe even do the same such as the bull shark, tiger, etc.
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