Bullmastiff vs Lion: See the Difference!

The Bullmastiff breed is a considerably large canine popular in both The United Kingdom and America. Famed for his seriousness in being a guard dog and a not-to-be-downplayed aggression level, there has been widespread speculation over who would stand a better chance in a fight between him and a lion. 

Lions are not new to us. In centuries past, this wild forest king has built up an impressive reputation as nature’s fatal ammunition against most animals it targets. Now, for Bullmastiff owners, asking to compare their pets to this king of the jungle is not uncommon. Let’s further discuss the details below. 

What Were Bullmastiffs Originally Used For?

The Bullmastiff is a new breed hailing from the United Kingdom mainly to serve as a guard dog. With many wealthy landowners who felt the need to protect their properties from poachers, it was necessary to look for options to aid them from this growing concern. This led them to hire gamekeepers who were given the responsibility to ensure that nobody trespasses the land.

Poaching is an illegal activity and the old times have matched it with a consequence of hanging when someone is caught doing it. This puts any gamekeeper’s life at risk since poachers wouldn’t hesitate to eliminate them rather than find themselves facing the gallows. 

Thus, the Bullmastiff breed emerged in the 1860s. They are strong and big enough to hold down an intruder. They were then tasked to patrol the grounds with their human companions and their presence created a positive change regarding poaching.

Would a Bullmastiff Fear a Lion?

A healthy and well-trained Bullmastiff who takes pride in his duty as a guard dog wouldn’t find the lion that daunting in case he spots it by his property. Although the lion is larger and exhibits an intimidating persona, some dogs wouldn’t easily back out. 

In fact, there has been a circulating video online of a dog who fearlessly tried to deal with a lioness. Although it wasn’t a Bullmastiff, seeing that it’s a dog gives us an initial conclusion that canines can show courage against bigger foes. 

However, bravery can be affected by several factors. If a Bullmastiff has been traumatized and gets easily jittery, he could scamper away and flee the scene while seeking refuge or any safer place. 

An untrained dog wouldn’t also have a clear sense of what he should do as a protector. Those who overly spoil their pets can cause a negative implication as well in a way like thinking that humans are responsible for guaranteeing their home and family’s safety and not the other way around.

Of course, both humans and their pet dogs have to work hand in hand in warding off suspicious individuals, but dogs are a family’s first line of defense. They will bark, alert, or if needed, attack a persistent trespasser until the owner shows up.

Comparing Features & Traits


Bullmastiff: The Bullmastiff dog stands tall at about 24 to 27 inches when measured at withers and weighs anywhere between 100 to 130 pounds. Females are lesser in proportions, yet they still are massive, especially as house pets. 

The breed has a broad and heavy face with a few wrinkles present on his face. He has a short and square muzzle with hazel eyes. The Mastiff trademark feature surrounds his nose and mouth while his small, dropped ears follow the same shade or lighter. 

The body is bulky, well-proportioned, and heavy. The dog exhibits a muscular appearance and strong legs to support his overall weight and his look is completed by a tapered tail that reaches the jocks.

Lion: Lions have superb features making him earn a respectable title in the wild. He has a large and compact body with sturdy legs, strong jaws, and a bushy mane that adds up to his size. An average lion can be 55.2 to 68.4 inches, more than twice the height of the Bullmastiff. He can weigh around 270 to 570 pounds as well which surpasses the marks of the Bullmastiff dog.

Photo from: johansmalman (IG)

The appearance of the lion is one of the most recognizable in the world. His features are simple, yet this animal is ferociously deadly. Aside from the mane possessed by adult lions, another unique thing about this animal is his tail which has a prickle at the tip.


Bullmastiff: When trained, the Bullmastiff would know when it would be necessary to show hostility. Still, his aggression level can be sparked easier compared to other breeds since he’s naturally unfriendly. If his property is being trespassed or his owner is being threatened, he will jump on the scene and deal with the foe by himself. 

Even if an individual doesn’t taunt or mock him, it remains unwise to approach a dog of this kind, more so when you know that he doesn’t recognize you. 

Lion: Lions are naturally vicious- a trait necessary for their survival in the wild. The intensity gets worse if they are hungry or provoked. Even if a lion is trained, it is still possible for him to turn to his owner. However, let’s recognize that different situations can trigger different behaviors. 

One thing is clear, however, and that is going near to a lion who is in the process of courtship or has cubs to protect will show extreme belligerence and must never be approached. 

Bite Force

Bullmastiff: Currently, there is no exact average measure on how strong the bite force is of the Bullmastiff. Knowing his heritage is composed of the Mastiff and the Bulldog can somehow give us a clue as to how dangerous it is to be bitten by such a dog. The Mastiff has an estimated 550 PSI, enough to chew off a big bone after just a few bites.  Meanwhile, the Bulldog has at least 307 PSI which is expected since he has strong jaws that can snap anything. 

Lion: The lion, once again, has the edge when it comes to biting force. He has at least 650 PSI which is scary enough for those who recognize how dangerous this wild animal is. Since his aggression level changes depending on the situation he’s in or the kind of behavior he exhibits, his biting force would also vary.

Hunting Tactics

Bullmastiff: Bullmastiffs weren’t bred to become hunting dogs. Sadly, he doesn’t have any background in going after prey, but his Mastiff ancestry has a hunting history in its bloodline. Still, as a distinct dog breed, hunting tactics are quite low for him. This doesn’t mean, however, that he has no instinct to hunt at all. At the sight of a smaller animal like a squirrel running to the tree, he will instantly have the thirst to go after it.

Lion: Lions hunt either along with their pride or simply do it alone. Generally, his technique is to stalk his prey and charge only when it’s about 30 meters near the target. His thirst to hunt is greater than the Bullmastiff, especially that he doesn’t know when he’ll be filled up again.

Motivation to Fight

Bullmastiff: It would only take anyone to cross the boundaries set by the Bullmastiff to provoke him into aggression. Since he values the safety of his family and the property he lives in, anyone would be unwelcome when the person is not recognized by the canine. And, even if you place him in a different setting wherein he could interact with other dogs, he’ll exhibit dominance which is quite problematic if he wasn’t socialized at a young age.

Lion: While lions are still cubs, they automatically have the mindset to train themselves how to fight which is why we often see on documentaries, little lions who play-fight a lot. This is necessary once they grow up to develop their competence to survive the harsh cycle of nature. 

Moreover, hungry or threatened lions will, no doubt, fight to the death.

Protective Instinct

Bullmastiff: A loyal Bullmastiff will protect his owner when the need arises. He is capable of pinning anyone to the ground thanks to his fatal features such as his jaws, paws, and heavy body that exhibits superb strength. Female Bullmastiffs, especially the mothers, mostly have a greater protective instinct. 

Lion: Female lions would find the need to defend their young and males, their pride and territory. If ever they also feast on their prized meat, they will attempt with all their might to shoo off unwanted guests. 

Does a Bullmastiff Stand a Chance Against the Lion?

In a one-on-one fight, no, the Bullmastiff wouldn’t stand a chance even if he’s in his best state. The lion has a lot of edges primarily in strength, size, features, and experience in fighting, making it easy to defeat anyone. It would take a much stronger breed of canine, greater in number, to defeat the king of the beast.