Saltwater Crocodile-Great White Shark interactions

[epaiva]

(04-05-2019, 01:16 PM)TheSmok Wrote: Crocodiles have a hydrodynamic efficiency coefficient of 0.7-0.9 (source). I do not have data on sharks, but bottlenose dolphin has an efficiency coefficient of 0.85, trout has an maximum efficiency coefficient of 0.75, and efficiency of trout and salmon was calculated at 0.7-0.9 (as in crocs, taken from here). Therefore, I can assume that in this case "comparable" is the same as "equal" and crocodiles spend as much energy on swimming as fully aquatic animals do. Oxygen consumption is not very important, as both sharks and crocodiles rely on anaerobic metabolism during high physical activity and crocs can hold their breath for 20-30 minutes during an active swimming, and have effective buoyancy change mechanisms for passive reaching the water surface. But crocs have a better anaerobic ability than sharks which roughly means that they have a better stamina. As for speed, in small size categories (using 3-meter total length for example) sharks really swim faster, but large sharks (using 5.5 meter great white sharks specimens for example) become disproportionately slow and seem to have same maximum burst swim speed as large crocodiles. I gave this data in past posts.

Lolong is not "largest crocodile ever measured from head to tip of the tail". There are a dried skin from Papua that actually (after addition a 72 cm skull) suggests a 6.3-meter long crocodile, which could be even larger (up to 6.7 meters) during its lifetime.
Data from Britton & Whitaker (2012):

Quote:After Lolong, the best documented evidence of a record-sizedcrocodile comes from Obo village on the Fly River in Papua New Guinea (Montague 1983). This crocodile drowned in a fishing netset for barramundi fish and after 50 men hauled the crocodileonto the bank they found an entire Rusa Deer (Cervus timorensis) carcass in the stomach. The crocodile’s skin had already beenremoved and salted when Jerome Montague and one of the au-thors (RW) visited the village, but the skin plus decapitated headmeasured 6.2 m (20.3 ft). The authors considered this likely anunderestimate considering possible shrinkage of the skin plusan incomplete tail tip, suggesting a TL closer to 6.3 m.

And data from personal email correspondence with Adam in 2014 (about 6,7 meter figure from Erickson et al., 2012):

Quote:The 6.7 m figure from the paper cites a popular book "Crocodiles and Alligators" written in 1989 by one of the paper's co-authors. I don't have that book to hand to double-check exactly what was said, but I believe both figures were citing the same paper.
The figure of 6.3 m that's on my website is based on the maximum length of an intact animal that's been measured (Montague et al 1983), although that was a head and skin that were added together to derive that length, and may have been slightly inaccurate. I believe Montague estimated that it could have been as long as 6.7 m which is perhaps where Webb derived that figure from, but the actual measure was 6.3 m. Neither is likely to be 100% accurate. Based on the size of the largest known C. porosus skull in the Paris Museum (measured after the Webb and Manolis book was published) and estimates I made in my paper on Lolong's maximum size (Britton et al 2013) I'd say the maximum size for C. porosus is probably closer to 7.0 m. Again that's still an estimate, which is why I think it's best to provide known maximum size (ie. actual measurements) with potential maximum size (estimates based on best-available evidence). I will update crocodilian.com to reflect this (there are several areas that need updating on the site, but time is limited these days!).

All measurements of Lolong can be found in Britton & Whitaker (2012) paper. And data on larger skulls can be found also in Britton & Whitaker (2012) paper, in my previous post and here (head length or HL corresponds to the dorsocranial length of the skull or DCL). I do not think that calculations from actually known skulls can be compared with such unverified data (and, as in the case of a 6-meter 7000-pound monster shark from Cuba, even refuted).
The point is not that the "crocodile with the same length is heavier" (in fact, the 6-meter great white shark will be about 2 times heavier than the 6-meter croc), but that the largest salties seems to have a greater verified lengths than the largest verified great whites (and be only on ~1/3 less heavy).

Very valuable information of measurements of Saltwater Crocodiles Reply