I'm working on a idea for a Gojirasaurus/Godzillasaurus species of dinosaur (a fictional dinosaur that was the dinosaur that would eventually become Godzilla due to the effects of radiation.)

The basic idea is that the dinosaurs, which were very similar to Acrocanthosaurus, lived on a landmass that was separated from the mainland and protected from the asteroid impact during the cretacous period.

These therapod dinosaurs eventually switched from a predatory, scavenging life style to a mostly herbivorous diet due to the lack of large game on their island (perhaps due to hunting it to extinction themselves.)

However, they are mostly herbivorous, as they also starting catching fish, as such they are also semi-aquatic filling a niche similar to hippos, bears, and Deinocheirus.

In order to reach the top of trees these dinosaurs adapted to a upright stance similar to there larger, mutated counterpart.

And in order to swim they develop large feet with loose skin/webbing in between they can use like fins, with a swimming style similar to modern ducks, also using a crockdilian tail to help with propulsion.

With a bipedal stance instead of a quadrupedal stance.

The dinosaurs are based of GMK Zilla.

With there legs evolving to be similar to sauropodean or Elephant legs in a pillar erect stance.

So since these dinosaurs are semi-aquatic I am wondering what foot type, may be the most advantageous for both environments.

Since the name Gojira, was based of the features of an Gorilla and Whale. I wondered in this world what gorilla like trait these dinosaurs might have in order to be compared to as such, and I thought.

Gorilla feet!

feet of a gorilla fully extended.

The scientific reason for this I've come up with is that the fourth toe grew longer in order to take more weight.

So here are three versions of the possible feet for these creatures I've come up with.

1.the skin wraps around the bone.

2.Skin and muscle grow around the toes making them look smaller.

3. A fusion of 1 and 2.

I did these quick on moto note so there not very good, the white is meant to represent bone while blue is meant to represent the outline of muscle and skin.

  1. Is a "shrink-wrapped" feet, where the skin or muscle doesn't stretch or grow between the fingers similar to a cassowary.

  2. Is a feet where skin and muscle grow around the toes leading to the toes looking smaller similar to a duck or crocodile.

  3. Is kinda a fusion between the two, where skin is loose between the first three toes but not the fourth.

I'm also wondering what foot type would be best.

  1. A plantigrade type.

my version of a plantigrade foot.

Or second.

  1. A digitgrade type.

My version of a digitgrade foot.

Both for stability for a large upright creature and for also swimming in shores and shallows.

Something I forgot to mention also was there long tail, with could perhaps act like a counterbalance similar to kangaroos

  • $\begingroup$ Having tried radiation mutation breeding on Bdelloid rotifers to no avail, ok I'm lazy, the pond is big and the Sun... anyhow may I know which is it preferred hunting ground the sea or the concrete jungle? $\endgroup$
    – user6760
    Jan 5 at 6:23
  • $\begingroup$ It's preferred hunting ground is the leaves on the top of trees. But that doesn't mean it doesn't spend substantial time in the sea. It's like a hippopotamus. $\endgroup$ Jan 5 at 17:16

2 Answers 2


When we're talking about a bipedal animal, body posture is largely irrelevant save that it means that the forelimbs do not take part in walking locomotion.

The main issues with this creature are that it is - or will evolve to be - particularly large, and that it will swim.

For a land-dwelling bipedal creature, the gorilla-like foot with its separated 'thumb' is not ideal. Humans evolved from chimpanzees and gorillas, and as the best bipedal runners of the three species, have non-separated big toes, not separated foot-thumbs. Digitigrade locomotion makes a creature faster by lengthening its stride, but it also allows better shock absorption. Elephants are digitigrade creatures, but their feet look flat because they have large shock-absorbing fatty deposits behind their toes. Its feet should look like those of an elephant or rhinoceros.

However, for a swimming creature, it would be desirable to have longer toes with webbing between them, in order to apply force to a larger volume of water. A gorilla-like foot is not ideal, since only the 'thumb' is long and separated, and not also all the other toes, and there is no webbing. Its feet should look more like a duck's - or a tyrannosaur's.

To have a creature that both walks and swims means that it would do neither as well as a creature evolved to do one or the other exclusively. That's the evolutionary compromise that must be made. The OP would have to decide if this is primarily a walking creature, primarily a swimming creature, or if it does both equally. Whatever the answer is, adaptations for one or the other should dominate, or should be somewhere in between the two extremes.


Here's something to think about:

enter image description here

The T-Rex, one of the largest bipedal dinosaurs, was digitigrade. All bipedal dinosaurs were digitigrade, actually, because their large tails acted as counterweights, which would make a plantigrade dinosaur very clumsy. As such, I would imagine that your Godzillasaurus would be digitigrade.

Hope that helps!

  • $\begingroup$ My main question for that though is whether or not it would be similarly advantageous for a upright standing dinosaur. As T-rex's stood horizontally. Also this dinosaur doesn't really need speed as the only megafauna on the island, it has no predators so it can be as slow as it wants. $\endgroup$ Jan 5 at 5:11
  • $\begingroup$ Btw unrelated but that picture of a T-Rex seems too have 5 toes, I always thought they only had 4. $\endgroup$ Jan 5 at 5:37
  • $\begingroup$ @TheGoldenBoy2188TheCoolestG It's not a good picture. The toe with its claw lying on its side appears to be a separate display. Consider upload.wikimedia.org/wikipedia/commons/4/4d/… $\endgroup$
    – Monty Wild
    Jan 5 at 5:44
  • $\begingroup$ BTW, their tails acting as counterweights is pretty much the least important factor in being digitigrade. $\endgroup$
    – Monty Wild
    Jan 5 at 5:47
  • $\begingroup$ @TheGoldenBoy2188TheCoolestG One thing to think about is that your creature doesn't need to be an effective swimmer to be an aquatic animal. Hippos actually CANNOT swim, nor float, nor breathe underwater - Instead, they run along the bottom of river beds. In a similar way, your Godzillasaurus could be partially aquatic to serve some other purpose (e.g hiding underwater to ambush prey on land ala crocodile or something else), but it's unlikely it would be able to be an ocean predator without sacrificing a lot of features to make it an effective water predator. $\endgroup$
    – Valitenci
    Jan 5 at 7:07

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