With late XXI century tech, wildlife replication is becoming commonplace. Dodos? Small dinosaurs are piece of cake. Dinosaurs? Large birds are big to deal with, but doable. So long you get a viable DNA sample, any animal can be replicated.

They need to be grown from infant stages (no insta-t-rex machine) and function as a normal born animal after that (by the way, some asian country now has a eternal dynasty of clones of their supreme leader, but that is for another day). They need to be tamed, trained, reared, shoed, etc.

Hunting and safari now are commonplace, because if you have enough biomass and energy, you can just keep making more animals. And of course the world is having tons of protests from animal rights defenders, but this is yet another tangent.

So Mr. McHound wants to get his killer hounds to fight all the animals there are. Is there any animal these dogs can't kill?


  • Land animals only. Of course the dogs will have no chance of killing an angler fish that never comes above 3,000 feet under the sea.
  • Only animals weighing more than 1lb. Don't go saying the dog can't chew tardigrades.
  • Hard Science question. Please take this in mind.
  • Any animal that ever lived on Earth with the requirements above is fine.


  • No genetically modifed animals. All the animals in the safari are standard versions of the ones that live(lived) on Earth.

Regarding the dogs:

  • The dogs are of a breed made for war created from several ferocious XX century breeds. They are not transgenic, but can be considered the pinnacle of canine crosbreeding.
  • Dogs can be cloned, and even though they have to be trained, if one dog of the pack survives, that is fine.
  • The dogs are trained for combat / killing / war.
  • Pack size is anything greater than 5 dogs.
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    $\begingroup$ What about poisonous animals which could be killed but would also kill the dog? What about animals that live where dogs can't hunt like in the rain forest, mangrove forests or swamps? If you throw dog after dog at the problem, any animal that can be reached will die of exhaustion eventually $\endgroup$ – Raditz_35 Jun 2 '17 at 12:46
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    $\begingroup$ "Pack size is anything greater than 5 dogs." I'll take near infinite dogs for the win? $\endgroup$ – apaul Jun 2 '17 at 15:08
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    $\begingroup$ This question is being discussed on meta: worldbuilding.meta.stackexchange.com/questions/5012/… $\endgroup$ – apaul Jun 2 '17 at 15:33
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    $\begingroup$ @apaul34208 What would win? Infinite dogs or the sun? $\endgroup$ – Frank Anderson Jun 2 '17 at 16:03
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    $\begingroup$ Your question is actually meaningless unless You set some constraints; i.e.: an upper bound to the size of the "pack". Can I have one hundred? one thousand? one million? How is the pack supposed to "attack"? Can dogs simply chase away or destroy the "prey" food till it starves? $\endgroup$ – ZioByte Jun 2 '17 at 17:21

Size and/or armor Elephants and black rhino can't be taken down by anything but the largest predators (or people) and even then they kill far more often then they get killed. Usually the predator is exploiting a specific weakness like drowning or literally climbing the animal which a dog will not be able to do. You can basically include any animal in the elephant size range or bigger. A large sauropod (especially the heavily armored ones) would not even be threatened by the dogs, they would just be an annoyance to be stamped into paste.

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    $\begingroup$ // , What are your sources for this? $\endgroup$ – Nathan Basanese Jun 2 '17 at 18:35

The obvious answer is any animal that can live somewhere that a dog can't go, such as up a tree or underground. Those are uninteresting cases, though, so I'll focus on what you were probably looking for: something that can co-exist in the same environment as dogs while being relatively immune to their attacks.

I'll also ignore the obvious answer that a pack of dogs - when fired from a cannon at a sufficient velocity - can probably kill anything[citation needed].

A dog's weapon for taking down prey is his mouth. Your target animal will therefore be something that a dog is physically unable to bite. I was unable to find any hard numbers about a dog's maximum bite size, but we can approximate this using other data. You mentioned these dogs were cross-bred for maximum hunting effectiveness. Let's assume that they have inherited the largest mouths/jaws from our modern day breeds and see what sorts of things they could bite.

After looking through tons of photos of dogs yawning from side angles, I was able to locate this photo. My protractor measured an angle of approximately 65 degrees between the upper and lower jaw, which is the largest of any of the photos I was able to find.

This wire basket muzzle is available in lengths up to 6 inches, the largest I found. The dog muzzle sizing guidelines state that a muzzle should not be longer than the dog's actual snout length, so there must be a breed with a 6" snout.

With these numbers, we can do a little trig to approximate the largest object a dog can bite:

$$ 2*\sin{\frac{\theta}{2}} * l_{snout} = 2 * \sin{\frac{65^{\circ}}{2}} * 6 = 6.45\ in. $$

Your uber-dog can open its mouth to a distance of almost 6.5 inches. This number is generous since it ignores the length of the teeth and assumes the dog would have any sort of bite strength when open at this extreme angle, but it can still serve as an upper bound. A dog would have difficulty biting anything significantly larger than this. An adult elephant's foot (for example) can be 15-20 inches wide, which would be very difficult for a dog to bite.

Your dog-resistant creature would need to have no accessible body parts that were small enough for a dog to grip. This means thick, long legs and a tough, tight hide that doesn't easily pinch or sag. The head would need to be far enough off the ground that a dog can't jump and grab the soft, squishy targets there (the record height for a dog's jump is 68 inches). This combination of attributes brings to mind the giant sauropod family of dinosaurs. If it lifted up its tail and neck, attacking dogs would have nothing they could effectively bite.

  • $\begingroup$ I like the fact that you actually did some research on this (even though that research wouldn't go far in a peer-reviewed journal), but I have to question the figure 6.5 inches (16.5 cm) that you end up with. I tried this with one of my dogs, who is hardly as big as the ones you assume and who had no trouble whatsoever grasping across some 11 cm. I didn't have anything appropriate conveniently nearby to try larger objects, but would hazard a guess that 12-13 cm is well within the realm of possibility even for that specific dog. Now scale that bite up some, and 16 cm doesn't seem so impressive. $\endgroup$ – user Jun 6 '17 at 18:18

Anything with thick skin. If the dogs can't damage it, they can't kill it. I also picked examples that were big enough to take out the dogs.

So, for modern animals: rhino, hippo and, maybe, elephant.

For extinct, recent, species, the giant sloth.

...the ground sloths' already thick hide consisted of osteoderms, which made it exceptionally thick.

Osteoderms are bits of bone material within the skin.

The saber tooth tigers in the American southwest (there were many, independent, instances of "saber tooth" tigers) developed their long fangs just to get through the thick hides of sloths and some other large mammals.

For extinct ancient species, the ankylosaurus or any similar species will fit the bill.


Large, armored lizards and amphibians may be the only ones that can fight dogs. Alligators would be unassailable by dogs in just a foot of water. Even if a dog could find the gator, one attack from the gator would kill a dog. With a group, the gator could just pick the dogs off one by one. If a dog did manage to bite the alligator, it would be ineffective due to its armor.

Komodo Dragons would be a formidable foe as well, with scaled armor, gigantic crushing bites, and a ludicrously strong tail. One bite or one direct hit from a tail would remove a dog from the fight.

Other than that, there are many land animals that live in places that Dogs simply cannot go. There are some primates, specifically species of Lemurs, that can live their whole lives in trees. Ibex can navigate cliffs so well that nothing can follow them. Burrowing animals are also suited to hide from dogs. These animals, while still being land animals, could never be reached by dogs.


What about tortoises? They cant kill it i suppose and the tortoises cant kill them. Is this a valid response or Should the animal in question be able to defeat/kill a dog?

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    $\begingroup$ I was thinking fleas $\endgroup$ – Separatrix Jun 2 '17 at 14:54
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    $\begingroup$ Actually dogs can kill tortoises, takes a while, but it's​ not unheard of. $\endgroup$ – apaul Jun 2 '17 at 15:04
  • $\begingroup$ @Separatrix Fleas are below the 1lb weight minimum. $\endgroup$ – sphennings Jun 2 '17 at 15:04
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    $\begingroup$ This question has been tagged with hard-science. That means answers must be backed up with scientific research with appropriate sources linked. $\endgroup$ – Azuaron Jun 2 '17 at 15:08

Your question is inherently opinion-based, and NO ONE pointed this out yet, but more about that later.

Honestly, your war dogs will gonna get r3ped by most land animals, just a few example:

  • Cattle (if very angry)
  • Elephants
  • Cats (if they're possessed by enough demons)
  • Horses and Giraffes (they can trample, and if clever enough to not get themselves surrounded, they can inflict a massive casualty upon the dogs)

Also, there is the...


This bird is/ can easily be a genocide crusader, with its sharp talons the Cassowary has more than enough tools to cut up Mr. McHound and his dogs.


Your dogs need to separate and overwhelm the prey, without any of these to they can be easily reduced to pillowy mounds of mashed potatoes (along with their owner), another crucial factor is that how angry, that animal is, if your dogs stumble upon Psycho Cat.

Another important thing is the animal's mind. If I spend months with teaching a Cassowary, how to effectively kill a dog, and how to avoid getting ensnared, then there's a good chance of the bird winning.

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    $\begingroup$ There's plenty of evidence of dogs killing, cattle, cats of all sizes, horses, and surviving quite well in Austraila $\endgroup$ – sphennings Jun 2 '17 at 13:24
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    $\begingroup$ I think you are severely underestimating the killing ability of a pack of trained dogs. $\endgroup$ – Arthur Dent Jun 2 '17 at 15:01
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    $\begingroup$ Let us continue this discussion in chat. $\endgroup$ – Mephistopheles Jun 2 '17 at 15:20
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    $\begingroup$ Eehh. I don't think this is a very good answer, quality wise, but it does have a few examples that are valid (that hadn't been mentioned before). Cassowaries and hippos probably have the upper hand (uh...foot?) over a pack of dogs. Mind, the dogs could still win, but it'd be a long shot. Redacted: if you could clean up your language a bit, I think this might become a reasonable answer. $\endgroup$ – Draco18s no longer trusts SE Jun 2 '17 at 17:50
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    $\begingroup$ A pack of wolves is a reasonable approximation to a pack of war dogs. Anything that can be taken down by a wolfpack (moose, bison, humans, etc.) can be taken down by a pack of war dogs. $\endgroup$ – Mark Jun 3 '17 at 0:06

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