American crocodile (Crocodylus acutus)

[KRA123]

(11-02-2023, 01:03 AM)Balam Wrote: @GuateGojira that's a great find. Orinoco crocodiles surpass in size both American crocodiles and black caimans with modern records of 5+ meter specimens, despite the massive overhunting. 

A mature Orinoco male from the Patrullero de Chávez breeding facility in Venezuela is claimed to measure 4.9 meters in lenght but with a weight of 730 kg. Orinocos are notorious for their weight relative to lenght as well.

The Nile crocodile is popularly regarded as the second largest crocodile in the world, but that's greatly disputed when we consider the historical sizes of Orinoco crocodiles which challenged even the largest salties. For context, no reliable record exists of a Nile crocodile above 6.1 meters in lenght, where despite their massive populations, males above 4.5 meters are very rare to come by.

The Neotropical crocodiles certainly deserve their dues in this regard.

Do the administrators at Patrullero de Chávez actually claim to have measured that crocodile, or just estimated it's lenght?

While I find it plausible that Orinoco crocodiles and even American crocodiles can grow to the same size as niles, I have a few points of contention regarding the possible size of Orinoco crocodiles relative to niles and saltwaters

Firstly, it is of course to be expected most nile crocodiles are under 5 meters. Most crocodiles of all species, even saltwaters, are under 5 meters. Crocodiles in excess of this are uncommon. Do you have a source for the statement that nile crocodiles over 4.5 meters are "very rare". Ideally this source should focus on mature males, since that is the only relevant demographic for the discussion. I'm interested to know if 4.5 plus mature males are any rarer in the nile species than in the Orinoco. Ideally that would have to be substantiated with data, which I don't personally have, and not just anecdotes about specific individual crocodiles. There is a video on youtube "Finding the largest nile crocodile" or something like that, where a guy measures several 4.5 plus niles at a single croc farm. I suspect that any of the four largest croc species will throw a few 4.5 meter plus individuals, but their species specific abundance would need to actually be quantified if you want to make that kind of comparison.

Regarding the largest skulls on record, the highest recorded DCLs for acutus and intermedius are quite high, but it should be remembered that the DCL to TL ratio might be different in the new world species than in the nile and saltwater. This is the case in tomistoma, the crocodilian with the largest recorded skulls. Personally, when I scale pics of acutus, niloticus and porososus taken from above, the head definitely seems to acocunt for a larger portion of the body length in the new world species, and if that appearance is real then that complicates exprapolating 6meter + TLs from the largest new world skulls.

Re the effect of hunting on the modern sizes of new world crocodiles: I can believe that hunting could have eliminated potential 6 meter crocs form C. acutus and C. intermedius. However, I don't believe hunting can explain why these two species have never been measured in excess of 5 meters in the modern era. All the large crocodiles were hunted extensively, yet you can still find 5.4 meter plus niles and saltwaters occasionally. Until we have a confirmed 5.5 meter measurement from the Orinoco and American crocodiles, I am also prepared to believe that these species simply top out at a lower TL (though perhaps similar DCL) to the giant old world crocodiles. Reply