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Comparing big cats - differences/changes with time
Comparing big cats - differences/changes with time
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Comparing big cats - differences/changes with time
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Hey guys. I had a question for you all, but I wasn't sure where to ask it.
I wanted your imput on certainly evolutionarily morphological ideas, i.e. why tigers and lions convergently evolved and how/why they differ physically from an adaptive POV & how jaguars diverged from other cats in their physicality and why. I have my own ideas on the matter, but I really wanted you guys' thoughts! If you can direct me to where I can ask these questions, or if you could answer them, it'd be greatly appreaciated. Thanks!  (02-16-2020, 06:03 AM)BlakeW39 Wrote: I wanted your imput on certain evolutionarily morphological ideas, i.e. why tigers and lions convergently evolved and how/why they differ physically from an adaptive POV & how jaguars diverged from other cats in their physicality and why. The usual "originating on separate far-off corners of the world" central America, sub-saharan Africa & fareast Asia seem very reasonable explanation. Ancestors of jaguars were split much earlier & stranded away on a whole new continent when Bering Land Bridge got submerged. Their similarities of physique with tigers are likely result of convergent evolution under comparable niche & habitat. (02-16-2020, 09:14 AM)Rishi Wrote:(02-16-2020, 06:03 AM)BlakeW39 Wrote: I wanted your imput on certain evolutionarily morphological ideas, i.e. why tigers and lions convergently evolved and how/why they differ physically from an adaptive POV & how jaguars diverged from other cats in their physicality and why. Thanks for your response! I don't want to mess up anyone's thread, so if I shouldn't speak on this here just let me know. I actually wasn't so much curious as to how they evolved from a genetic POV (i.e. lion/jaguar lineage splits from tigers, then lions and jaguars split and go opposite directions); moreso in why they evolved adaptively for their physical structure. So like why tigers and lions got to be the same size, and moreover what differences are between them (build? muscularity? etc) and what pressures drove the similarities and differences or how/why jaguars evolved their abnormally large skulls, short limbs, and squat frames, and why the needlessly strong jaws. Sorry if I'm inconvenient: I just thought this was a really interesting topic but didn't know where to get you guys' take. Thanks :)  (02-16-2020, 08:29 PM)BlakeW39 Wrote:(02-16-2020, 09:14 AM)Rishi Wrote:(02-16-2020, 06:03 AM)BlakeW39 Wrote: I wanted your imput on certain evolutionarily morphological ideas, i.e. why tigers and lions convergently evolved and how/why they differ physically from an adaptive POV & how jaguars diverged from other cats in their physicality and why. Prey, Climate and terrain. For example, I wouldn't be surprised if Pantanal Jaguars look more like Otters than Cats in the next couple 100 years. They've already begun to have webbed toes and long, curved spines. (02-16-2020, 09:00 PM)Rishi Wrote:(02-16-2020, 08:49 PM)Pckts Wrote: ...I wouldn't be surprised if Pantanal Jaguars look more like Otters than Cats in the next couple 100 years. No, i don't think they'll need that much time. You already see it now, their small ears, large skulls, dense orbital area, webbed toes, long, articulating spines, etc. They've already begun the transition to a water dominate animal, those characteristics have become dominate and will be passed quickly. I'm not saying they're going to look exactly like an otter, just that they'll be much more similar to them than any other big cat. (02-16-2020, 09:07 PM)Pckts Wrote:(02-16-2020, 09:00 PM)Rishi Wrote:(02-16-2020, 08:49 PM)Pckts Wrote: ...I wouldn't be surprised if Pantanal Jaguars look more like Otters than Cats in the next couple 100 years. Why? Hadn't they already been there for many thousands years?.. Did said changes appear in them over past century only & weren't noted in Pantanal Jags before that? (02-16-2020, 09:50 PM)Rishi Wrote:I'm not sure how long they've been there for but the pantanal has extreme conditions which is why you see distinguishable differences between them and their neighbors in the amazon.(02-16-2020, 09:07 PM)Pckts Wrote:(02-16-2020, 09:00 PM)Rishi Wrote:(02-16-2020, 08:49 PM)Pckts Wrote: ...I wouldn't be surprised if Pantanal Jaguars look more like Otters than Cats in the next couple 100 years. And with the increase in Caiman over recent years it seems to be expediting that evolutionary process. Their prey is limited there, especially in the north and I think that is why they've adapted quickly to adjust for their Caiman rich diet. (02-16-2020, 10:06 PM)Pckts Wrote:(02-16-2020, 09:50 PM)Rishi Wrote:I'm not sure how long they've been there for but the pantanal has extreme conditions which is why you see distinguishable differences between them and their neighbors in the amazon.(02-16-2020, 09:07 PM)Pckts Wrote:(02-16-2020, 09:00 PM)Rishi Wrote:(02-16-2020, 08:49 PM)Pckts Wrote: ...I wouldn't be surprised if Pantanal Jaguars look more like Otters than Cats in the next couple 100 years. It's worth mentioning that unlike the lion, leopard and tiger, the jaguar is believed to be a monotypic species, meaning that it has no subspecies, despite the physical and geographical differences between different populations, like the Pantanal and Mexican jaguars: https://onlinelibrary.wiley.com/doi/abs/...0.CO%3B2-E (02-16-2020, 10:21 PM)BorneanTiger Wrote:The classification of subspecies is a debatable one, which is why modern science seems to be shrinking it.(02-16-2020, 10:06 PM)Pckts Wrote:(02-16-2020, 09:50 PM)Rishi Wrote:I'm not sure how long they've been there for but the pantanal has extreme conditions which is why you see distinguishable differences between them and their neighbors in the amazon.(02-16-2020, 09:07 PM)Pckts Wrote:(02-16-2020, 09:00 PM)Rishi Wrote:(02-16-2020, 08:49 PM)Pckts Wrote: ...I wouldn't be surprised if Pantanal Jaguars look more like Otters than Cats in the next couple 100 years. The differences between mexico and the pantanal are vast, even between the Amazon and the pantanal, there are many factors. For instance, in the Amazon during the floods, Jaguars have become sloth hunters and spend most of their time in trees while in the pantanal they dont have that option which is why they are the most aquatic big cat. What little dry land they have gets washed away and changes every season and the prey they hunt are much more aquatic as well. But this has also led to the largest version of them too. You can use Lions and Tigers too, for instance, Crater Lions are distinct from the Serengeti lions even though they are essentially the same species but the crater being cooler with more rain and better year round grazing for prey seems to contribute to a much more dense mane that covers the shoulders as well as a more robust cat. Bengals also show extreme variations even within the same subspecies, I really think the only thing that matters in evolution is habitat, climate and prey base. If we were to designate every cat with slight variations as a sub species than the classifications could be endless. (02-16-2020, 08:49 PM)Pckts Wrote:(02-16-2020, 08:29 PM)BlakeW39 Wrote:(02-16-2020, 09:14 AM)Rishi Wrote:(02-16-2020, 06:03 AM)BlakeW39 Wrote: I wanted your imput on certain evolutionarily morphological ideas, i.e. why tigers and lions convergently evolved and how/why they differ physically from an adaptive POV & how jaguars diverged from other cats in their physicality and why. Good answer, I think the same, on your first statement at least. I think jaguars evolved to have the most generalized diet of big cats. This is because the tropical rainforest they've adapted for uniquely biodiverse but yet lacks the large herbivores found elsewhere. This may have been exacerbated by the Quarternary extinctions that marked the end of large xenarthrans and notoungulates. So in response to this, jaguars adapted to take advantage of a very diverse, and usually smaller, prey base. Because of this, different physical adaptations were required. This smaller prey often consisted of armored reptiles. They likely evolved disproportionaly large heads & powerful jaws take advantage of reptiles as well as kill moderately sized mammals in an efficient way that may not have worked for larger animals (skull bite). Indeed, even when available, jaguars seem not to prefer large mammals like tapirs. Their short limbs were maybe a response to their habitat and prey base as well, whereby they didn't need to be as cursorial and with short limbs could stalk their prey more effectively. I don't think they'll look like otters soon though haha. That specialization wouldn't be advantageous in their habitat, especially when competition is not that high.
Competition in the pantanal is 2nd to none, but for the most part I agree with you.
But when you see Jaguars, you realize how similar their body is to a giant river Otter. Obviously they're still very different but, they still share similarities that no other big cat shares. This has got to do with the fact that they're hunting animals that are more adept in the water than land. I'm not saying that they'll stop running on land, I'm just comparing their features to that of a specialized aquatic predator. In regards to large mammals, they dont occur nearly as often in north, whether due to human hunting or Jaguar densisty is up for debate but regardless, they just dont exist like that in the North. The main animals you see there are capybara and Caiman. They're both very adept swimmers and never stray far from the waters edge. They also usually sit with one another so they probably require the same tactics. Tapir are no slouch, they can be double the size of a male jaguar. But they are predated on more often in the areas they are more abdundent. Put it this way, if you go on safari in the northern pantanal, the odds of you seeing a tapir are 1/100. (02-17-2020, 03:01 AM)Pckts Wrote: Competition in the pantanal is 2nd to none, but for the most part I agree with you. Well competition in the Pantanal is high (not sure if I'd say second to none though) with pumas, caimans, and anacondas. I was mostly speaking of terrestrial predators, though. But yeah I definitely see their similarities with river otters. I think these characteristics are derived from different naturally selective pressures, though; the jaguar's long, flexible spine, for instance, is an adaptation for a different behavior than is the similarly long and flexible spine of the otter. The former is for great agility & athleticism for predation, while the latter is for swimming. I totally agree that jaguars are the most aquatic of the big cats, mostly due to the fact which I stated on them taking advantage of a diverse prey base that largely includes semi-aquatic animals. But jaguars are generalists, and I doubt they'd specialize in this aquatic prey when they also take other animals, like giant anteaters. Yeah tapirs aren't slouches, though they should be well within the capabilities of a jaguar sized felid. It's also worth noting that they're also rather aquati, and they're largely nocturnal. They also live at low densities being large solitary animals with rather slow maturation and gestation periods. But nevertheless mammalian megafauna don't make up a significant portion of the jaguars diet in way it usually does for the other extant big cats. (02-17-2020, 07:26 PM)BlakeW39 Wrote:In regards to competition, I'm speaking on intraspecific ones. In that regards, I'd say the jaguar has the highest densisty of cats in a localized area.(02-17-2020, 03:01 AM)Pckts Wrote: Competition in the pantanal is 2nd to none, but for the most part I agree with you. And I'm not talking about females and cubs, I'm talking about adult specimens and mostly males. In the meeting of the 3 rivers *tourism zone of the northern pantanal* there were 65 identified adult individuals last season. Cubs there are rarely seen and usually are pushed out to never be seen again. Tapir are rarely seen in the north, in the south they are seen more often but still rare. My theory is the reason tapir and green anaconda are rarely seen in the north is because of the densisty of Jaguars. Both are slowing moving animals that may prefer a more vast space with a lower density of Jaguars. It's kind if a perfect storm in the north, caiman were hunted and killed by the millions, decreasing jaguar numbers and increasing piranha numbers, when protection was finally offered to Caiman, they rebounded fast due to the increase in piranha after missing their main predator. Now Caiman are everywhere, same with Capybara and both are mostly aquatic animals. Cattle is a large ungulate and obviously easily killed by Jaguar. Tapir are going to be a tough animal to kill for any cat, especially one that they are double the size of. Boar that are equal size as cats can be extremely tough prey, when they're double the size of a cat they are going to be very dangerous prey. Lastly, in regards to their spine, it definitely contributes to Jaguars agility in the water. They are so comfortable in the water and make kills in the water as well then they need to swim animals from the water up a steep, slippery slope and through dense floating grass. It's a perfect combination of flexibility and strength, but with the ever changing habitat and aquatic prey preference, it should only benefit the Jaguar to continue its aquatic evolution imo.  (02-16-2020, 11:29 PM)Pckts Wrote: The classification of subspecies is a debatable one, which is why modern science seems to be shrinking it. This is a very good point about the subspecies clasification. The great mayority of the old subspecies of tigers/lions/jaguars/leopards are based in very few specimens, sometimes only "one" soecimen and some cases those were captive specimens! Those clasifications are incorrect and should be avoided completelly. Genetic and morphological evidence with tigers and lions suggest only two "subspecies" but others defend more. However, what is the evidence that they have? They support the "subspecies" issue with little genetic evidence that can be explained as simple splits caused by human actions in the habitat, or they say that they "look" different with is a very "victorian" point of view and completelly invalid. Even people like Selous said that the lions look very different in a single area that is futile to try to separate them in groups. @Pckts give an excelent example with the lions in the Crater and those from Serengeti, they look very diferent but they are the same subspecies. Also the Bengal tigers are so different between populations that someone could clasify a lot of subspecies in the subcontinent but all of them are the same (Ranthambore, Kanha, Nagarahole, etc. etc.), in fact only those from Sundarbans shows real adaptative diferences with those of the other areas and are clasified as its own evolutionary conservation unit; other example are Caspian and Amur tigers, with even less differences than those of Sundarbans/India-Nepal and with a separation of only 200 years! The point is that animals adapt to they habitat but those adaptations are clinal or based in prey availability and type of terrain, but that doesn't means necesarily that they are going to be a different "subspecies". Even worst, the concept of "subspecies" is still not well defined and the one used with tigers, at least is the one of Dr Kitchener which demands that there should be at least a difference in the 75% between populations and that is something that can be done only with the Mainland and the Sunda tigers. Now, about the adaptations, the Amur/Caspian and the Sundarbans tigers have adapted completelly to they own habitat that they are clasified as a different population that should not be merge with the other ones, but there is no significant diference between Indian-Indochina-Malaysia populations, just some diferences in size and weight, but not different enough to separate them as "subspecies" per se. At the end, speaking of tigers, the populations are now so separated that the humans had actually created "artificial subspecies" with tigers from the Indian subcontinent completelly isolated from other areas, tigers in Indochina surviving only in Thailiand and probably Myanmar, Malayan tigers with a fragmented population only at the end of the itmus of Kra and the Amur tigers completelly isolated in the Russian far east, so none of those populations have the small change to mix in modern days. The key is in the zoos, where these groups are allready separated and should be keep in that form. As far I know, and also based in the posts of @"Bornean Tiger", the separations of lions is the same thing, lions from the East and South of Africa are diferent from those from West/North Africa and Asia. Only those from the central region of Ethiopia looks like a mix of the two populations, but we don't have data from wild animals, just captive ones from Addis Ababa Zoo. About jaguars, like @Pckts says, there are huge differences in habitat and prey and that reflect they differecens in size too, but at the end they are just a single subspecies with adaptations to they habitat. It is incredible that in just a few hundred of years these cats had addapted so well and reflect differences in they morphology and is also incredible until what degree the humans had influenced in the natural world. |
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