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Post by creature386 on Sept 12, 2019 23:17:30 GMT 5
Could it be that the greater level of endothermy possessed by the mako shark simply makes it more hungry for larger prey?
Or do hammerheads not just seek small prey in comparison to mako sharks, but also compared to sharks in general (relative to their size, of course)?
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Post by theropod on Sept 12, 2019 23:48:58 GMT 5
Well, most sharks target such small prey, but most sharks are smaller than Great Hammerheads.
But yes, Makos certainly have higher metabolic rates and would require more food. So perhaps them attacking larger prey is out of necessity.
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Post by dinosauria101 on Sept 12, 2019 23:50:56 GMT 5
theropodAbout small hammerhead prey size, the hammer would present a very vulnerable target; it's an exposed vital area, and an injured shark cannot usually hunt.
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Post by Grey on Sept 12, 2019 23:55:28 GMT 5
Of course, but like you said previously while talking about fossil animals, the natural behavior and agression level itself is something to consider, in that case we can. Of course the mako was not going to kill the great white just like the honey badger won't kill an adult lion. But the hammerhead is not a great white in terms of overall weaponry, physiology and body mass. And the mako in question did not seem to be particularly large. |
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Post by theropod on Sept 12, 2019 23:58:13 GMT 5
Ok, so this may well be the longest table I’ve ever posted here, but I thought it was worth it, so everyone can mix and match their own sharks as they want:
FLio: Fork Length Isurus oxyrinchus, Kohler et al. 1996
FLsm: Fork Length Sphyrna mokarran, Cliff 1995
BMio: Fork Length Isurus oxyrinchus, Kohler et al. 1996
UD: Upper dentition length, Lowry et al. 2009
[BMhh1: Body Mass Sphyrna mokarran, Cliff 1995]
[BMhh2: Body Mass Sphyrna lewini, Kohler et al. 1996]
BMsm: Mean of BMhh1 and BMhh2
masses in kg, length measurements in m
"TL" "FLio" "BMio" "UDio" "FLsm" "BMsm" "UDsm"
"1" 1.5 1.38 27.3 0.27 1.06 16.05 0.15
"2" 1.55 1.42 30.3 0.28 1.1 17.8 0.15
"3" 1.6 1.47 33.52 0.29 1.14 19.67 0.16
"4" 1.65 1.52 36.96 0.29 1.18 21.67 0.17
"5" 1.7 1.56 40.63 0.3 1.23 23.8 0.17
"6" 1.75 1.61 44.55 0.31 1.27 26.07 0.18
"7" 1.8 1.65 48.72 0.32 1.31 28.48 0.19
"8" 1.85 1.7 53.14 0.33 1.35 31.03 0.19
"9" 1.9 1.75 57.83 0.34 1.39 33.73 0.2
"10" 1.95 1.79 62.79 0.35 1.43 36.58 0.21
"11" 2 1.84 68.04 0.36 1.47 39.58 0.21
"12" 2.05 1.89 73.58 0.37 1.52 42.75 0.22
"13" 2.1 1.93 79.42 0.38 1.56 46.08 0.23
"14" 2.15 1.98 85.57 0.38 1.6 49.58 0.23
"15" 2.2 2.03 92.03 0.39 1.64 53.26 0.24
"16" 2.25 2.07 98.82 0.4 1.68 57.11 0.25
"17" 2.3 2.12 105.94 0.41 1.72 61.14 0.25
"18" 2.35 2.17 113.41 0.42 1.76 65.36 0.26
"19" 2.4 2.21 121.22 0.43 1.8 69.77 0.27
"20" 2.45 2.26 129.4 0.44 1.85 74.37 0.27
"21" 2.5 2.3 137.94 0.45 1.89 79.17 0.28
"22" 2.55 2.35 146.86 0.46 1.93 84.18 0.29
"23" 2.6 2.4 156.16 0.47 1.97 89.39 0.29
"24" 2.65 2.44 165.86 0.47 2.01 94.81 0.3
"25" 2.7 2.49 175.96 0.48 2.05 100.44 0.31
"26" 2.75 2.54 186.47 0.49 2.09 106.3 0.32
"27" 2.8 2.58 197.4 0.5 2.13 112.38 0.32
"28" 2.85 2.63 208.76 0.51 2.18 118.68 0.33
"29" 2.9 2.68 220.56 0.52 2.22 125.22 0.34
"30" 2.95 2.72 232.8 0.53 2.26 132 0.34
"31" 3 2.77 245.5 0.54 2.3 139.01 0.35
"32" 3.05 2.82 258.66 0.55 2.34 146.27 0.36
"33" 3.1 2.86 272.3 0.56 2.38 153.77 0.37
"34" 3.15 2.91 286.42 0.56 2.42 161.53 0.37
"35" 3.2 2.95 301.03 0.57 2.46 169.55 0.38
"36" 3.25 3 316.14 0.58 2.51 177.83 0.39
"37" 3.3 3.05 331.76 0.59 2.55 186.37 0.4
"38" 3.35 3.09 347.89 0.6 2.59 195.18 0.4
"39" 3.4 3.14 364.56 0.61 2.63 204.27 0.41
"40" 3.45 3.19 381.75 0.62 2.67 213.63 0.42
"41" 3.5 3.23 399.5 0.63 2.71 223.28 0.43
"42" 3.55 3.28 417.8 0.64 2.75 233.21 0.43
"43" 3.6 3.33 436.66 0.65 2.79 243.43 0.44
"44" 3.65 3.37 456.09 0.66 2.84 253.95 0.45
"45" 3.7 3.42 476.1 0.66 2.88 264.77 0.46
"46" 3.75 3.47 496.71 0.67 2.92 275.89 0.46
"47" 3.8 3.51 517.91 0.68 2.96 287.31 0.47
"48" 3.85 3.56 539.72 0.69 3 299.05 0.48
"49" 3.9 3.6 562.16 0.7 3.04 311.11 0.49
"50" 3.95 3.65 585.21 0.71 3.08 323.48 0.49
"51" 4 3.7 608.91 0.72 3.13 336.18 0.5
"52" 4.05 3.74 633.25 0.73 3.17 349.21 0.51
"53" 4.1 3.79 658.24 0.74 3.21 362.56 0.52
"54" 4.15 3.84 683.9 0.75 3.25 376.26 0.53
"55" 4.2 3.88 710.23 0.75 3.29 390.3 0.53
"56" 4.25 3.93 737.25 0.76 3.33 404.68 0.54
"57" 4.3 3.98 764.96 0.77 3.37 419.41 0.55
"58" 4.35 4.02 793.36 0.78 3.41 434.49 0.56
"59" 4.4 4.07 822.48 0.79 3.46 449.94 0.57
"60" 4.45 4.12 852.32 0.8 3.5 465.74 0.57
"61" 4.5 4.16 882.89 0.81 3.54 481.91 0.58
"62" 4.55 4.21 914.2 0.82 3.58 498.45 0.59
"63" 4.6 4.25 946.25 0.83 3.62 515.37 0.6
"64" 4.65 4.3 979.07 0.84 3.66 532.66 0.61
"65" 4.7 4.35 1012.65 0.85 3.7 550.34 0.61
"66" 4.75 4.39 1047.01 0.85 3.74 568.4 0.62
"67" 4.8 4.44 1082.15 0.86 3.79 586.86 0.63
"68" 4.85 4.49 1118.09 0.87 3.83 605.71 0.64
"69" 4.9 4.53 1154.83 0.88 3.87 624.96 0.65
"70" 4.95 4.58 1192.39 0.89 3.91 644.62 0.65
"71" 5 4.63 1230.77 0.9 3.95 664.68 0.66
"72" 5.05 4.67 1269.99 0.91 3.99 685.16 0.67
"73" 5.1 4.72 1310.05 0.92 4.03 706.05 0.68
"74" 5.15 4.77 1350.96 0.93 4.07 727.36 0.69
"75" 5.2 4.81 1392.74 0.94 4.12 749.1 0.7
"76" 5.25 4.86 1435.38 0.95 4.16 771.27 0.7
"77" 5.3 4.9 1478.91 0.95 4.2 793.87 0.71
"78" 5.35 4.95 1523.33 0.96 4.24 816.91 0.72
"79" 5.4 5 1568.65 0.97 4.28 840.39 0.73
"80" 5.45 5.04 1614.88 0.98 4.32 864.32 0.74
"81" 5.5 5.09 1662.03 0.99 4.36 888.7 0.75
"82" 5.55 5.14 1710.11 1 4.4 913.53 0.75
"83" 5.6 5.18 1759.13 1.01 4.45 938.82 0.76
"84" 5.65 5.23 1809.1 1.02 4.49 964.58 0.77
"85" 5.7 5.28 1860.02 1.03 4.53 990.8 0.78
"86" 5.75 5.32 1911.92 1.04 4.57 1017.49 0.79
"87" 5.8 5.37 1964.79 1.05 4.61 1044.66 0.8
"88" 5.85 5.42 2018.65 1.05 4.65 1072.31 0.81
"89" 5.9 5.46 2073.51 1.06 4.69 1100.44 0.81
"90" 5.95 5.51 2129.38 1.07 4.73 1129.06 0.82
"91" 6 5.55 2186.26 1.08 4.78 1158.18 0.83
"92" 6.05 5.6 2244.18 1.09 4.82 1187.79 0.84
"93" 6.1 5.65 2303.12 1.1 4.86 1217.9 0.85
Code:
sharkmorph<-data.frame(TL=seq(1.5,6.1,0.05))
sharkmorph$FLio<-0.01*(0.9286*(sharkmorph$TL*100)-1.7101)
sharkmorph$BMio<-(5.2432*10^-6*(sharkmorph$FL*100)^3.1407)
sharkmorph$UDio<-(10^-0.778*(sharkmorph$TL*1000)^1.009)
sharkmorph
sharkmorph$FLsm<-(((sharkmorph$TL*100-0.825*17.10)/(1+0.825*0.35))*1.064-6.09)/100
sharkmorph$BMhh2<-7.7745*10^-6*(0.7756*(sharkmorph$TL*100)-0.3132)^3.0669
sharkmorph$BMhh1<-1.71*10^-5*((sharkmorph$TL*100-0.825*17.10)/(1+0.825*0.35))^2.9435
sharkmorph$BMsm<-(sharkmorph$BMhh1+sharkmorph$BMhh2)/2
sharkmorph$UDsm<-(10^-1.780*(sharkmorph$TL*1000)^1.244)*0.001
sharkmorph<-round(sharkmorph,2)
sharkmorph$BMhh1<-NULL
sharkmorph$BMhh2<-NULL
write.table(file="sharkmorph.dat", sharkmorph, sep="\t")
References:
Cliff, G. 1995. Sharks caught in the protective gill nets off KwaZulu-Natal, South Africa. 8. The great hammerhead shark Sphyrna mokarran (Rüppell). South African Journal of Marine Science 15 (1): 105–114.
Kohler, N.E., Casey, J.G. and Turner, P.A. 1996. Length-length and length-weight relationships for 13 shark species from the western North Atlantic. Fishery Bulletin 93: 412–418.
Lowry, D., de Castro, A.L.F., Mara, K., Whitenack, L.B., Delius, B., Burgess, G.H. and Motta, P. 2009. Determining shark size from forensic analysis of bite damage. Marine Biology 156 (12): 2483–2492.
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Post by dinosauria101 on Sept 12, 2019 23:58:22 GMT 5
theropodSeems I missed that one. I suppose both you and Grey have a point. Still leaning towards the mako.
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Post by theropod on Sept 13, 2019 0:10:28 GMT 5
Of course, but like you said previously while talking about fossil animals, the natural behavior and agression level itself is something to consider, in that case we can. What do you mean I said? I recall saying that specifically with fossil animals, we do not know the behaviour or aggression level. And both Great Hammerhead and Shortfin Mako are extant animals anyway. Now undoubtedly the Mako has some clear advantages in the athleticism, aggression, and prey size categories here, but I doubt they would outweigh a 2-fold size advantage, considering all the above. Yes, but I also don’t think these encounters are very informative in general. That a Cougar can drive off a Grizzly Bear does not mean we should favour a Cougar over a Jaguar either, even though a Jaguar clearly is no Grizzly. No, it certainly is not. But it’s not a common dolphin either, in fact at their real relative sizes, it looks like the Hammerhead may well be twice the weight of the Mako, and have an at least equally potent bite. |
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Post by dinosauria101 on Sept 13, 2019 1:17:55 GMT 5
Yes, but I also don’t think these encounters are very informative in general. That a Cougar can drive off a Grizzly Bear does not mean we should favour a Cougar over a Jaguar either, even though a Jaguar clearly is no Grizzly. Not sure how much water this holds but I've heard it said in the ruins of AE that intimidation often happens due to a large risk of death (maybe less than 50 percent but still, quite a bit) for the animal that's being intimidated |
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Post by theropod on Sept 13, 2019 1:32:52 GMT 5
I think this is the exception rather than the norm.
Try a little thought experiment. How would you go about catching a house cat, bare handed? I suspect you’d be very cautious, perhaps to the point of not even trying it at all, because you would want to prevent getting bitten or scratched by it even though it doesn’t represent a high risk to your life, correct?
Nature is full of examples like this. Even orcas often prefer to smash seals to death with their flukes rather than go in jaws first and risk a scratch to their faces.
Likewise, I don’t think a honey badger represents a high risk of death to a lion, nor does a cougar to a grizzly, realistically speaking. But either still doesn’t want to get bitten or clawed by the smaller animal, even if the smaller animal likely wouldn’t be able to cause serious damage. And presumably, a great white shark doesn’t want to get bitten by a Mako either, even though the mako doesn’t represent a high risk to its life. Certainly, it also wouldn’t want to get bitten by a Hammerhead, there just isn’t a comparable interaction on record.
Nevertheless, GWS prey on Makos, that alone should be obvious demonstration that the interaction in question doesn’t mean much as to Makos’ presumed dominance, and certainly not that GWS are afraid of them or something like that.
Of course animals will also be intimidated by something that actually does represent a serious threat to them. But most animals would probably avoid interactions of that sort completely (hence why most predators almost never attack prey their own size), although a few apex predators and other particularly aggressive animals might engage in them (usually when they offer good prospects of food).
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Post by dinosauria101 on Sept 13, 2019 1:46:52 GMT 5
Yes, you've got a point there I suppose. An injured shark IS at serious risk
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Post by Grey on Sept 13, 2019 3:17:28 GMT 5
On average, I would give this to the hammerhead. Using a 4 m mako, it is a different matter. Not mentioning the huge but special case of the freakish female.
I wonder if there is today somewhere another comparable specimen...
But of course who knows about the hammerhead freaks even if there is zero record of them.
Just like the alleged GWS caught in Senegal in the 80's, observed by a marine biologist who could not take any picture but was sure it was around 9 m long.
Or the infamous case of "Submarine", many find it a dubious but an actual shark researcher confirms to have seen a gigantic GWS with his father in those waters in the 70's. After all, such GWS appear to have existed some million years earlier.
Sure, the freaks and problematic individuals should be discarded but they could be put in very specific matches.
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