1. Walrus vs polar bear
The fight: A walrus can weigh up to a ton - three times as much as a polar bear. But the polar bear, described as the most carnivorous of all the bears, has a natural advantage: it lives off the flesh of seals - a similar foe to their tusked cousins. With the blubbery walrus's 4ft tusks and the bear’s 3in canines, this battle on the ice always looks likely to get bloody - and it does.
Steve Bunce says: The walrus has the best killing tools in nature but is at heart a pacifist, which is not good in a fight against a permanently angry polar bear.
Result: Walrus gets eaten.
2. Hippo vs elephant
The fight: Hippos are responsible for more human fatalities than any other animal on the savannah. But this one faces a formidable foe. The elephant can grow to more than seven tons, and has a tripartite attack- it's capable of impaling, charging or delivering a skull-crushing stomp. The aggressive hippo should have known better, as the elephant tosses it aside.
Steve Bunce says: Big is not always best - but then again big is not often a four-ton edge over a hippo.
Result: An easy win for the elephant.
3. Dog vs shark
The fight: A bull mastiff-type dog, fearsome on land, seems to be the obvious loser the minute it leaps from the deck of a boat to face a 6ft Great White shark - one of the planet’s most dangerous predators - in its natural habitat. Yet somehow, with pluck and wile (and possible assistance from a fishing line), the mutt soon has the fish safely on dry land.
Steve Bunce says: The dog is a novice paddler, and the shark is fighting at home. But the shark has already been done by a good hook.
Result: Dog lands shock win.
4. Moose vs wolf pack
The fight: A pack of grey wolves close in on a young moose at a watering hole in the Alaskan wilderness. Each wolf has a mouth full of jagged teeth capable of exerting twice the pressure of a German Shepherd’s bite. But the moose has her young to protect - and boy can she stamp. "Never, ever get a mother angry" seems to be the moral, but patience and stamina also come into play...
Steve Bunce says: An angry mother with zero fighting skills against a pack of cowardly savages: this is the type of fight the Las Vegas bookies like.
Result: Wolves win - eventually - but know they’ve been in a fight.
5. Bullfrog vs sparrow
The fight: The importance of fighting on familiar territory is demonstrated here again. Despite being able to zip through the air at 28mph, the sparrow loses out once it is dragged from the lily pad on which it has landed into the water. The bullfrog can weigh up to 20 times as much as the bird, and this little sparrow is frog food.
Steve Bunce says: The idiot sparrow likes to give it plenty of verbals and tends to stay around to admire his insults.
Result: Sparrow isn't agile enough, and gets eaten.
6. Lions vs wildebeest vs crocodile
The fight: Things can get hairy at the waterhole. When a pride of lions ambushes a pack of wildebeest at a South African national park, it all kicks off. Quick as a flash, the lions have a baby 'beest in the water. As they drag it out, a crocodile spots an opportunity and sinks its teeth into its hindquarters. But there’s more, as the bizarre-looking safari cows come back for vengeance...
Steve Bunce says: One dumb animal will always lose to a smart animal with bigger teeth, a few friends and an empty belly - but what about sixty angry dumb beasts defending their young?
Result: Too chaotic to call - but probably a sore draw.
7. Honey badge vs monitor lizard
The fight: The monitor lizard: a big, powerful, scaly, prehistoric beast that may have inspired myths of the dragon. The honey badger: a 30-inch-long, weasel-like creature which in earlier times would have made someone a rather fetching hat. But don't be fooled by appearances: with neck skin a quarter of an inch thick and ferocious defensive abilities, the furry native of Africa and South Asia is an animal built to survive a fight.
Steve Bunce says: This badger is a craftsman, a master of counter-boxing, and it moves beautifully against the stone-faced favourite.
Result: One ex-lizard.
8. Otter vs alligator
The fight: You'd think there could be only one winner - but there's a shock in store. Had you taken a punt on this furry otter as it clashed with a juvenile alligator at Lake Woodruff National Wildlife Refuge in Florida, you’d be laughing all the way to the bookies’ window. It knows its enemy, and sneaking up from behind, gets its teeth into the reptile’s fleshy neck, and suddenly there’s the mother of all upsets.
Steve Bunce says: Even a tiny crocodile should be able to take an otter out with just one bite. But bigger shocks have happened...
Result: An otter triumph.
9. Pepsis vs tarantula
The fight: A pesky pepsis might seem like easy work for a poison-fanged arachnid that can weigh in at up to five ounces. But the flying fighter, nicknamed the tarantula hawk, soon has the spider paralysed on its back. The wasp then lays a single egg in the spider's abdomen.
Steve Bunce says: The tarantula has a sucker punch, and the size, and home advantage. But the hornet looks like it needs a good meal.
Result: Hornet wins.
10. Two tigers vs bear
The fight: As a young sloth bear frolics with two baby tigers, little does he know mummy and daddy tiger are round the corner. And they're not happy. Debate rages in the comments section of the YouTube video as to who won. The bear certainly puts up a good fight.
Steve Bunce says: A friendly bear in the wrong place at the right time. It's tag team time.
Result: Tigers shade it.
11. Rattlesnake vs hawk
The fight: A gruesome clash of brains and brawn. Using its 50-inch wingspan to distract the serpent, the hawk leads with its feet, clawing at the earthbound rattlesnake, before finishing it off with a series of pecks to its increasingly bloodied head. Avoiding its venomous fangs, the bird employs a classic tactic and goes for the snake’s, literal, blind spot - its poor vision.
Steve Bunce says: A classic encounter between a KO artist and a pretty-boy mover .
Result: Hawk's skill wins it.
12. Sealion vs octopus
The fight: This Australian sealion almost bites off more than it can chew as it snaps at a passing octopus with a view to a quick seafood snack. All eight legs are soon engaged, slapping at the sea mammal's side. But the fight doesn't last long, and without any real defensive armour the octopus soon becomes the freshest sushi supper on the high seas.
Steve Bunce says: The octopus has the reach but does it have the brains to avoid being dinner?
Result: Octopus eaten.