This probably sounds fairly ridiculous- I know, but in short I've been developing a sort of future earth. It's not extraordinarily accurate, but I've been trying to at least keep the obvious in check. As far as I've seen, there's really no long legged semi aquatic animals, and it's easy to see why.

Still, is there any way one could develop in such way? Something like a cheetah in the process of adapting to adapt to a new environment, maybe in the very early stages? I've been using cheetahs as a reference, as the made up creature is built (somewhat) similarly. I considered if it could be initially an animal built for chasing down its prey, but another more successful species made that life style too hard for our "cheetah". This sent it to another niche, fishing, which its specialized form isn't built for exactly, but is changing rather quickly to adapt to.

This was the best I could come up with, but I honestly found it much too complicated to be plausible. Could something like this potentially happen, or is there an even more reasonable explanation? My end goal is to keep the creature relatively the same, with its long legs, longish muzzle, and small eyes and ears, but to also keep it along rivers.

  • 6
    $\begingroup$ There are plenty of long-legged semi-aquatic animals, it's just that most of them (all, AFAIK) happen to be birds: storks, herons, cranes, flamingos, and other wading birds. They have longish "muzzles", too. Perhaps mammals never evolved into this niche because the burrowing habit of K-T extinction survivors made swimming an easier path to a semi-aquatic niche. $\endgroup$
    – jamesqf
    Commented Jan 24, 2018 at 4:32
  • 1
    $\begingroup$ as @jamesqf points out, there are plenty of long-legged wading birds, so it would not be unreasonable for mammals to similarly develop. A lot of grazing animals do have relatively long legs. However, swimmers tend to have shorter legs, so there would need to be advantages to wading, as opposed to swimming. $\endgroup$
    – Lee Leon
    Commented Jan 24, 2018 at 9:16
  • 3
    $\begingroup$ Small point: your creatures must have already had some talent at fishing prior to their competition showing up, or they would just have died out. If that’s the case you don’t actually need a competitor species: your original species just splits into the ones who are better at chases and the ones who are better at exploiting the swamp niche. $\endgroup$
    – Joe Bloggs
    Commented Jan 24, 2018 at 9:19
  • $\begingroup$ Tigers and jaguars are the cats that living in swamps the most. So make your cheetahs halfway to jaguars. As a side note, in the situation you are mentioning, evolutionary pressure is large so eveolution will happen fast. A creature halfway between cheetah and jaguar won't be 'stable' for long; it will quickly (hundreds of thousands of years) evolve one way or the other, to optimize for its environment. $\endgroup$
    – kingledion
    Commented Jan 24, 2018 at 12:05
  • 1
    $\begingroup$ Another thought: perhaps a 4-legged form is not conducive to a wading lifestyle? If you watch wading birds, they seem to feed by pivoting at their hips, something that a quadruped couldn't do well. So your semi-aquatic mammal would either have to evolve a very long neck (like sauropods), or evolve from a biped. And since the only true bipedal mammals are humans, your far-future Earth has a branch of humans evolve this way. $\endgroup$
    – jamesqf
    Commented Jan 24, 2018 at 19:58

1 Answer 1


Moose are very long legged and while most of them don't spend long periods of time in swamps, some do. In Northern Canada most moose spend the majority of the summer and early fall in swamps, often up to their necks to avoid mosquitoes. Several types of antelope live in swamp, while most of them tend to be on the small side, their legs are comparatively long to help them walk through the water.

With big cats, tigers are what you should be looking at for ideas. All tigers enjoy the water as a means to cool down, but some live in swamps full time. Their large paws help them move over the muddy ground, their fur keeps the water away from their skin and dries off quickly, and their long legs help them move through the water either by swimming or walking.

Having a cheetah forced to move into a swamp would generally mean the death of the cheetah. A cheetah would have many problems surviving, as they're sprinters and built as such, while the swamp is not really made for it.

However if it took long enough it's possible. They'd need wider paws, longer water repelling fur, and instead of sprinting more of a very fast leap or lunge would work better. Their attack style of moving very slowly towards the prey until the last second would help quite a bit, making them an ambush predator. Most likely they`d start out living on the fringe of the swamp stalking shore birds and animals coming for a drink, until enough generations had passed to allow them to adapt to living in the swamp itself.

Long legged animals can handle a swamp fairly easily, it's everything else that's a problem.

  • 2
    $\begingroup$ Was just thinking of tigers amd panthers. Also consider polar bears, which swim for miles already! Maybe the melting icecaps resulted in polar bears evolving an even more aquatic lifestyle! Although they do have a fairly different body shape compared to cheetahs. $\endgroup$ Commented Jan 24, 2018 at 9:29
  • $\begingroup$ Polar bears are already about as aquatic as they can be while still having legs. One researcher was asked what would happen if the ice sheets melted, and he replied, "They'll have to swim another fifty or a hundred kilometers instead of the 3 or 4 hundred kilometers they already do." $\endgroup$
    – Dan Clarke
    Commented Jan 24, 2018 at 14:15
  • $\begingroup$ As far as I know, polar bears currently hunt exclusively on land or ice. Which is why you always see the image of a starving polar bear to raise awareness for the melting icecaps. The OP could make them develop a taste and need to hunt fish and seals in the water itself, while still needing land to give birth amd raise their young etc. $\endgroup$ Commented Jan 25, 2018 at 0:49
  • 1
    $\begingroup$ WRT polar bears, swimming isn't the same as wading. There are lots of swimming mammals, from beaver & otters through seals & walruses all the way to the cetaceans. Indeed, the black/brown & grizzly bears are about as close as you can get to mammals that feed by wading, at least in salmon spawning season. $\endgroup$
    – jamesqf
    Commented Jan 25, 2018 at 4:34
  • 1
    $\begingroup$ @DanClarke. Oh I didnt say the starving polar bear was an absolute true fact, just that you see that image being used for awareness/marketing purposes 😉 it is true that there are other swimming mammals. They are more adapted/streamlined for hunting/living in water, which is why I ended up zeroing in on the polar bear as it had a larger land based requirement. I had realised the OP wanted some sort of river creature not a polar creature which is also why I didn't think it was worth a full answer. Hopefully the OP can use the theory behind these ideas to develop their creatures. $\endgroup$ Commented Jan 25, 2018 at 9:33

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .