
Simbakubwa kutokaafrika, or the Hyena-lion: the real Warg?
Though Tolkien described the landscapes of Middle-earth in great detail, he didn’t go much into its animal life, and when he did it was similar to what you’d encounter on a walk in the English countryside. With the addition of various fell creatures, of course. But these were met only if you wandered far and were out on an adventure.
Nevertheless, I thought I’d talk about what kind of ecosystem this Europe-sized piece of land possibly held. Who ate who, and who was at the top?
First of all, monsters both good-natured (eagles, Beornings) and evil (wargs, dragons, giant spiders) were rare, and Tolkien tells us so. Spiders lived only in a few dark, dank, out-of-the-way places. Dragons were a dying race and existed only in the far north – Smaug was the exception. Wargs raided only at Sauron’s command. Balrogs dwelt in deep caves and so did the tentacled nameless horrors alluded to by Gandalf.
As for animals, Tolkien mentions only wolves and bears, which for a Europe-sized, thinly populated area of diverse habitats doesn’t make much sense.
So what else might there have been?
Middle-earth has always had a Pleistocene vibe to me so I can see the mix of animals there. Tolkien didn’t say what species his bears were, but by their size and ferocity, I’d guess they were Grizzly bears, also known as Brown bears. More commonplace, less intelligent bears might have been the smaller Black bear, which actually come in colors other than black. But there were larger bears in Earth’s prehistory, among them the Short-faced bear (Arctodus simus) and the Cave bear (Ursus spelaeus). Either one would have been a formidable threat to large prey like elk, moose, or the Irish elk that King Thranduil rode in the Hobbit movie trilogy.

The silly-looking but deadly Short-faced bear, compared to a human.
Wolves came in three varieties: wild wolves, werewolves, and wargs. None are treated kindly by Tolkien. Wild wolves are animals, basically the modern species, which surely must have radiated out into a mix of subspecies according to habitat. Wolves are mentioned as coming to the edges of The Shire during one arduous winter, so it can be inferred they normally avoid human settlements except for times of stress.
Werewolves are those wolves Morgoth, and later Sauron, turned towards evil and bred into giant and terrifying forms. They are not werewolves in the sense of modern horror depictions: they don’t change back and forth into humans by the moon’s phases, and those they kill don’t become werewolves either. In some places they seem more like evil spirits in the shape of wolves, rather than wolves themselves. What’s clear is that they are servants of their master who can’t act independently, so they can’t be said to have a hand in the local ecosystem.
Wargs are Sauron’s improved version of werewolves (or Tolkien’s, rather – they were created after the werewolves.) Like the former they are giant, monstrous wolves, but in addition they had the power of speech and a higher intelligence. In The Hobbit and The Rings of Power they are unlovely creatures that resemble hyaenodonts more than wolves.

Wargs from The Hobbit movie trilogy
Though not related to hyaenodonts, which were a pre-Carnivora species, wild hyenas surely had a niche in Middle-earth. Though long thought of cowardly and opportunistic (and portrayed so in Disney’s Lion King movie) they are formidable cooperative killers in their own right. Pleistocene hyenas were large and well adapted to cooler climes.

Prehistoric Cave hyenas
In fact there’s a good case for wargs actually being prehistoric hyenas. Though mustelids (related to weasels and wolverines) and not canids, hyenas are pack hunters, exceptionally fierce, and down large prey by sheer persistence. They are built for function, not beauty.
Big cats are not mentioned in The Hobbit and LOTR, but they must have been there. Tigers, pumas, and snow leopards populate temperate and colder climes in the modern world, and up to the 5th century genetically modern lions roamed Europe. There were even larger lion species previous to this, such as the Cave or Steppe lion (Panthera spelaea) of the late Pleistocene. Tolkien mentions lions only in Hobbit poetry and a few Elvish writings, and then as living in the Far East; but I bet there were plenty of stealthy big cats in Middle-earth no one knew about, living far from human-inhabited areas. Which is to say, all over the place, as Middle-earth during the eras of the novels wasn’t too populated.
And why was that? The fault of The Plague, of course!
But back to lions. There is also a complete lack of lion iconography in Middle-earth. When animals are mentioned as being on coats-of-arms or shields, they are, invariably, eagles, Tolkien’s go-to predator crest animal. From this I can deduce that whatever Middle-earth lions looked like, they lacked the picturesque manes of their real-world counterparts. Otherwise they would have found their way into human admiration, the same way Europeans continued to use lions as decorative elements even as they existed many miles away in Africa.
Pards, short for leopards, are also mentioned in Hobbit poetry, but not to any great description. They too are described as living in the East. But like lions, they also had a warmly furred Pleistocene subspecies that lived in European climes up to 12,000 years ago. Both lions and leopards have been identified in cave paintings by early humans in Spain and France. There’s good evidence black panthers, escapees from the safari parks of the 1970s, have colonized parts of England today, and survived.
So I’d say there were big cats in Middle-earth, they were just stealthy and unspectacular.
And what of Eagles as an apex predator? They are certainly large enough to carry off a deer or two, but from the books, they are rare, singular beings and fussy about where they live, which is only the highest mountains. I can see them picking off chamois or bighorn sheep from the higher altitudes. Which might bring them into conflict with human shepherds at some point, but that’s another story. In any case, their presence or lack of it isn’t going to significantly change the ecosystem, just because there are so few of them.
The large prey animals of Middle-earth, the ones Tolkien mentioned anyway, were deer, wild cattle (aurochs), boars, and wild horses, asses, and donkeys. He doesn’t go into speciation, but for a European Pleistocene vibe, I’d say there were roe and fallow deer, elk, and some extinct cervines like the Stag-moose (Cervalces scotti) and the Irish elk or Megaloceros.

A recreation of the mighty Stag-moose, one of the largest cervines ever to exist
Wild horses must have been around too, part of the Valar’s original animal seeding. But there were also horses in Aman (Valinor) that were of a higher order: faster, better-looking, more noble, more intelligent, a four-footed compatriot to Manwe’s Eagles, perhaps. These wiser horses interbred with the Eastern horses to create singular mounts like Shadowfax and Windfola. I can see herds of primitive wild horses still roaming the plains around the Sea of Rhun.
Wild cattle, like long-horned aurochs, buffalo, bison, and European wisent would have served as heavy browsers. Yaks would have roamed colder areas and many kinds of sheep and goats for mountains and hills.

The Kine of Arawn?
There would also have been antelope analogs on the plains and in Harad. Most people think of antelope as native to Africa, but there are some species living in central Asia, among them the Tibetan antelope and the droop-snouted Saiga. Like horses, they are plains and steppe animals. But for Middle-earth, a more unusual animal is called for. I think the American Pronghorn fits the bill. Pronghorns are the sole remaining species of their family, Antilocapridae, and their closest relatives are giraffes. They are odd-looking but fleet herbivores that, in the past, boasted a variety of even odder-looking horns. I think they’d fit in fine.

Tetrameryx shuleri, a prehistoric pronghorn
In getting this far in my writing I’d forgotten about trolls. Some trolls serve Sauron, while others are just ordinary blokes, like the three that capture Bilbo and the Dwarves. My feeling is the bloke-trolls live, during the day, in caves, and keep livestock like sheep and goats for their dinners while also capturing the occasional humanoid. They are just about intelligent to pull this off. I admit I am inspired by the Greek myths in this, those of Geryon and the Cyclops. The trolls who serve Sauron do it for something else, a promise of treasure perhaps.
All this brings us to the mumakil. There’s nothing in LOTR to suggest they’re anything other than ordinary elephants, the Hobbits’ awe at them caused by their own diminuitive size and the sheer shock of seeing such a large creature. I rather think they’re African elephants, like Hannibal’s, bonded to their keepers and prone to temper tantrums. African elephants can reach up to 13 feet high at the shoulder and are more than capable of carrying a howdah with multiple archers. The kaiju-like size of the mumakil in the Peter Jackson movies is, of course, an exagerration for dramatic effect, like the titanic underground halls of Moiria. If you must make sense of it within the movies’ context, it’s entirely possible Sauron had a hand in their creation, the same way he created the fellbeasts (the common name for the Nazgul’s flying, reptilian mounts).
There were also rhinoceros-like creatures drawing some of the Easterling’s war wagons, so there was a niche somewhere for these creatures as well.
As always, this is just speculation on my part. But I do wish we’d see some of it reflected in future productions.