The hippopotamus is responsible for more human deaths in Africa each year than any other large land mammal, and its bite is the primary reason why. At roughly 1,800 PSI, delivered through a mouth that opens wider than any other land animal’s, a hippo’s bite is not just powerful — it is a weapon evolved almost entirely for violence between hippos, that happens to be catastrophic for anything else caught in its path.
Hippo Bite Force: 1,800 PSI
The bite force of the common hippopotamus is measured at approximately 1,800 PSI (pounds per square inch), equivalent to roughly 8,100 Newtons of force.
This figure traces back to a measurement taken by wildlife researcher Dr. Brady Barr for National Geographic’s Dangerous Encounters series, in an episode built around capturing exactly this data from a wild hippo. Barr’s readings have since been repeated across countless wildlife references — though, as with the similarly Barr-sourced figure for the Nile crocodile, it represents a single field measurement rather than a large, peer-reviewed dataset, a caveat worth keeping in mind when treating the number as precise.
Critically, the measurement was taken from a female — by most accounts the more practical subject, since male hippos are considerably larger and more dangerous to approach for testing. This matters because hippos show significant sexual dimorphism in exactly the anatomy that generates bite force: a peer-reviewed study in Biology Letters found that while male and female hippos differ in overall body mass by only about 5%, male jaws average 44% heavier than female jaws, and male canines average 81% heavier. The bite force of a large, mature bull — never directly measured — is generally assumed to exceed the widely cited 1,800 PSI figure by a meaningful margin.
How Does 1,800 PSI Compare to Other Animals?
| Animal | Bite Force (approx.) |
|---|---|
| Human | ~160 PSI |
| Dog (large breed) | ~300–400 PSI |
| Lion | ~650 PSI |
| Tiger | ~1,050 PSI |
| Gorilla | ~1,300 PSI |
| Polar bear | ~1,200 PSI |
| Hippopotamus | ~1,800 PSI |
| Saltwater crocodile | ~3,700 PSI |
| Nile crocodile | ~3,700–5,000 PSI |
| Great white shark | ~4,000 PSI |
At around 1,800 PSI, the hippo has roughly 11 times the bite force of a human, nearly three times that of a lion, and more than the polar bear — the largest terrestrial carnivore on Earth. Only the largest crocodilians and a handful of shark species clearly exceed it among living animals, and even then, as our hippo vs crocodile comparison explores, raw PSI is only part of the story: the sheer width of a hippo’s jaw and the length of its canines mean the practical damage it inflicts often exceeds what the number alone suggests.
Why the Bite Is So Wide — and So Dangerous
The hippo’s jaw opens to 150–180 degrees, roughly four times the maximum angle of a human jaw, creating a gape of up to 1.2 metres (4 feet) across at full extension — the widest mouth of any land mammal, according to multiple wildlife references including Encyclopaedia Britannica.
This extreme width isn’t incidental to the bite force — it’s part of what makes the bite so destructive. The wider the jaw opens, the greater the mechanical leverage available when the powerful temporalis and masseter muscles snap it shut, and the more of an opponent’s body the jaw can enclose in a single closure. A bite from a hippo has been documented severing the body of a large Nile crocodile in a single motion — a level of damage that reflects the combination of force, jaw width, and the 50 cm canines described in our hippo teeth guide, not force alone.
The Warning Before the Bite
Hippos rarely bite without warning first. The wide-open mouth display — commonly called the hippo “yawn” — is not a yawn at all. It’s a deliberate threat display, exposing the full canine array to communicate aggression before any physical contact occurs.
Wildlife guides across Africa learn to read the typical escalation sequence: the yawn and head-swinging, followed by vocalisation (deep honks and grunts), then mock charges, and only then — if the warnings are ignored — a real charge and bite. Recognising the early stages of this sequence, rather than waiting for the final one, is genuinely life-saving advice for anyone near hippo territory.
How Hippos Use Their Bite in the Wild
Territorial Combat
The primary real-world use of a hippo’s bite is not hunting — hippos are herbivores — but combat between rival bulls. Territorial fights involve both animals opening their mouths to full gape and clashing canines in a series of powerful strikes aimed at the flanks, neck, and face. These fights can be prolonged, and the wounds inflicted are frequently severe or fatal.
The scarring visible on older dominant bulls — heavy, layered marks across the neck and flanks — is essentially a visible record of a hippo’s fighting history, built up bite by bite over years of territorial defence.
Defence Against Predators
When threatened by a predator, or more commonly by a human, a hippo’s bite is close to an absolute deterrent. A single bite from an adult is generally sufficient to kill or severely incapacitate virtually any terrestrial predator that gets too close, including lions, hyenas, and crocodiles — a fact explored in depth across our hippo vs comparison series.
Infanticide
Less discussed, but well documented, is the use of the bite by dominant bulls against calves — particularly young males — as a way of eliminating future competition. It’s one of the more significant, and least visible, natural threats hippo calves face in their first year of life, alongside crocodile predation. Our guide to hippo predators covers this in more detail.
Frequently Asked Questions
- What is hippo bite force in PSI? The hippopotamus has a bite force measured at approximately 1,800 PSI (around 8,100 Newtons), recorded from a female hippo by Dr. Brady Barr for National Geographic. Male bite force is widely believed to be higher, given males have significantly heavier jaws and canines, but it has not been directly measured.
- Is a hippo’s bite stronger than a lion’s? Yes, considerably. A hippo’s bite force of roughly 1,800 PSI is nearly three times that of a lion, which bites at approximately 650 PSI.
- Is a hippo’s bite stronger than a crocodile’s? No. The Nile crocodile’s bite, at 3,700 to 5,000 PSI, is stronger in raw force than a hippo’s. However, a hippo’s much wider jaw gape and longer canines mean the physical damage it can inflict in a single bite is often more severe, which is why hippos consistently dominate encounters with crocodiles despite the lower PSI figure.
- How wide can a hippo open its mouth? A hippo can open its jaw 150 to 180 degrees, creating a gape of up to 1.2 metres (4 feet) at full width — the widest mouth of any land mammal, roughly four times the maximum jaw angle a human can achieve.
- Why do hippos open their mouths so wide if they eat grass? The wide gape isn’t for eating — hippos graze using their lips and molars. It exists purely as a weapon and threat display: maximising bite leverage in combat, and communicating aggression to rivals or perceived threats before any physical contact occurs.
- Can a hippo bite kill a human? Yes, easily and often instantly. Hippos are responsible for an estimated several hundred human deaths across Africa each year, and a direct bite is frequently fatal given the combination of bite force, jaw width, and canine length involved.
Explore more on Hippoworlds: hippo teeth — anatomy and the ivory trade · hippo vs crocodile · how dangerous are hippos to humans · how fast can hippos run
I’ve been writing and running HippoWorlds’ content since 2019. I lived in Angola and was lucky enough to see hippos in the wild in Botswana and South Africa — I’m not a scientist, but a curious enthusiast dedicated to making this site a serious reference on the species.