Modern Weights and Measurements of Jaguars

[peter]

(03-18-2017, 09:51 AM)epaiva Wrote:

(03-18-2017, 09:40 AM)sanjay Wrote: Thats a big difference for sure. May be age difference @epaiva ?

@sanjay

They are both adult male Jaguars but Jaguars in the Venezuelan Llanos are the second largest after Pantanal  Jaguars  they weight up to 120 kilograms and Jaguars from the Amazon in Venezuela are a lot smaller with the largest ones weighting  up to 65 kilograms.

What you see isn't a result of age or individual variation, but circumstances. There are more factors, but good conditions top the list. When you read about Amur tigers, habitat destruction, prey depletion and smaller size, go this this post.

Wild big cats can survice in barren regions and forests, but they like plains with rivers and patches of forest better. The reason is these attract herbivores. Large herbivores.

Surinam and French Guyana, not that far away from Venezuela, have dense tropical forests. Their beauty is second to none, but it isn't easy to make a living. Tropical forests are not ideal for hunters. Large animals are few and far between and small animals are, ehh, too small for a decent big cat. This is why smaller cats, like ocelots and golden cats, thrive in these conditions. Sumatra, also densely forested, is the exception to the rule. Half a century ago, it had many large animals. Sumatra still has elephants.   

Skulls of Surinam jaguars, although larger than the smaller skull posted by Epaiva, are decidedly smaller than those from the Llanos. Same for skulls of pumas shot in Surinam.

The Amazon forest, however, can produce large jaguars. Not as large as those in Venezuela or the Pantanal, but they can be large. I saw pictures of people who had been in the Amazone Basin a long time. They knew where to find large jaguars. I noticed most of these had been shot near (large) cities. Jungle cities often are surrounded by farms. Jungle animals like farms, as new opportunities. As jaguars like opportunities as well, some of them can get quite big. Not saying they compare to the Yellowstone bears who thrived near dumps, but open spaces, crops and plenty of opportunities usually produce larger animals than tropical forests and mountains. It isn't always easy to make a decent living in the natural world.     

The jaguar skulls I measured roughly ranged between 220-300 mm. The longest skull belonged to an animal allegedly shot in the extreme south of the US well over a century ago. Seems a bit unlikely, as jaguars in that region are smaller than those of the Pantanal and the Llanos. I'll post some pictures later.
 
Very interesting information, Epaiva. Many thanks. Reply