Looking at today’s birds, it’s hard to imagine they’re the direct descendants of dinosaurs, perhaps the largest and deadliest animals to ever walk the Earth.
However, all it takes is a quick look at a few birds on this list for you to realise that not only are they descendants of dinosaurs, they are – quite literally – dinosaurs themselves.
A lot of prehistoric birds filled niches once occupied by their reptilian ancestors, living in the same environments, growing to giant sizes, and hunting similar prey. And unlike the dinosaurs they descended from, many of these prehistoric birds flew, making them even more terrifying.
From two-metre-tall ‘Terror Birds’ that could outpace a peloton of professional cyclists, to giant storks that preyed on primitive, hobbit-like humans, here are 10 of the deadliest birds from prehistory.
- Dinosaur teeth from formidable carnivore discovered in English countryside
- 10 most epic prehistoric discoveries of 2024
- Dinosaur mass extinction: what caused it, which dinosaurs went extinct, and how mammals survived
Titanis
This flightless giant belongs to a diverse group of predatory birds known as phorusrhacids, or ‘Terror Birds’.
The clue is in the name when it comes to these particular birds; they were the apex predators in South America for a long, long time – from 43 million years ago (Mya) to just 100,000 years ago.
Titanis was one of the largest of these so-called ‘Terror Birds’, standing 2m tall and weighing in at over 300kg. It had a huge skull with a deadly-looking, hooked beak that researchers think it used to peck its prey to death.
It was fast too, with some studies suggesting it could sprint at speeds of more than 40mph. And on top of all that, it swallowed its prey whole.
Titanis lived across the savannas that once covered large parts of southern North America. It preyed on many of the mammals that also lived there, including horses, tapirs, and extinct relatives of today’s armadillos known as Glyptotherium.
Titanis is unique in that it’s the only predator known to have successfully crossed from South America into North America during an event known as the Great American Interchange.
Other predators that also made the journey north were quickly outcompeted by North America’s superior wolves, cats, and bears.
Haast’s Eagle
Māori legends speak of a beast known as the pouākai – a giant, monstrous bird that is said to have terrorised villages and hunted humans. This fictional bird is widely considered to be inspired by the very real but now-extinct eagle known as Haast’s eagle, or Hieraaetus moorei.
While there’s no evidence that it actually hunted humans, researchers think that it would definitely have been capable of doing so.
- Meet the world's deadliest-ever eagles
- Fierce, majestic and deadly: your ultimate guide to the world's biggest birds of prey
Haast’s eagle weighed roughly 18kg and had a wingspan that spanned almost 3m, making it the largest species of eagle currently known to science.
From the Pleistocene (around 1 Mya) up until its eventual extinction in 1445, Haast’s eagle was endemic to the South Island of New Zealand.
It primarily hunted giant, flightless birds known as moas that, at 230kg, were twice as heavy as today’s largest flightless birds, ostriches. It’s thought that by overhunting moas, the Māori may have inadvertently driven Haast’s eagle to extinction.
Haast’s eagle looked similar to today’s eagles, only larger. It had huge, curved talons, a hooked beak and – according to its depictions in historic Māori cave art – a bald head.
Together, these adaptations paint a picture of a bird that would have fed by plunging its head deep into the body cavities of its prey to get at nutritious organs.
Giant stork
Not all storks deliver babies. In fact, at least one stork from prehistory is thought to have dined on babies, rather than delivered them to expectant mothers.
This baby-eating bird is known as Leptoptilos robustus and it lived on the Indonesian island of Flores from the Middle to Late Pleistocene (100,000-50,000 years ago).
Leptoptilos robustus stood 1.8m tall and weighed up to 16kg, making it one of, if not the largest predator on Flores at the time.
From studies of its fossilised remains, researchers think it would have looked a lot like its close living relative, the Marabou stork (Leptoptilos crumenifer). This stork has cloak-like wings, skinny legs, and a pink head topped with wispy white hair.
It’s thought that, like today’s storks, Leptoptilos robustus was a scavenger. However, it may have also been a predator that actively hunted a small, primitive species of hominin that also lived on Flores, Homo floresiensis.
The babies of these diminutive humans would have been at particular risk from Leptoptilos robustus and may have even been small enough for these giant storks to swallow whole.
- 8 weirdest bird beaks: Discover some avian oddballs
- 10 petrifying prehistoric beasts that would have terrified early man
- Best dinosaur documentaries to watch
Elephant bird
There are several different species that belong to the now-extinct group of massive birds known as elephant birds. The largest amongst them is the aptly-named Aepyornis maximus – a contender for the ‘largest bird of all time’, standing 3m tall and breaking the scales at nearly a ton.
Like today’s ostriches, elephant birds were flightless. They also laid eggs larger than those laid by the largest dinosaurs, sauropods.
These eggs weighed around 10.5kg and were large enough to hold the contents of nearly 180 chicken eggs.
To grow such large eggs, female elephant birds are thought to have drawn on reservoirs of calcium they stored in their femurs.
It’s thought remains of these elephant bird eggs, found by early explorers, may have inspired legends of giant birds, like that of the infamous roc from Middle Eastern mythology.
As a group, elephant birds were native to Madagascar and lived there for several thousand years, only facing extinction as recently as 1,000 years ago when humans first settled the island and started destroying their habitat.
Some are believed to have grazed on low-lying plants, while others are thought to have used their long necks to browse higher vegetation for fruits.
Argentavis
Argentavis resembled a small biplane when airborne, with a wingspan that measured approximately 7m across. It was incredibly heavy too; tipping the scales at 72kg it was at least 54kg heavier than the heaviest flying bird today, the kori bustard.
Still, Argentavis isn’t the heaviest flying bird on this list – but more on that particular behemoth later.
Argentavis lived in what is now Argentina during the Late Miocene (9-6.8 Mya), and would soar over the area’s mountains and plains as it searched for fresh carcassess, just like its modern analogue the Andean condor does in the same part of the world today.
It actually looked quite similar to a condor, although its skull and beak were a lot more robust.
By studying the size and structure of Argentavis’ wings, researchers have come to the conclusion that it flew by soaring, using flapping flight only in short bursts.
It’s also thought it would have used cliffs and slopes as launchpads, taking a short run-up before jumping and spreading its wings.
Having such large wings would have made it difficult for Argentavis to move around on the ground, which suggests it was more likely a scavenger than a predator.
Garganornis
Few animals have more of an attitude than geese. They may be relatively small, but these birds are fearless and are known to pick fights with animals many times their size, including humans.
It’s likely their extinct, flightless ancestors known as Garganornis had the same brazen attitude.
Garganornis lived in Gargano, Italy, during the Late Miocene (9-5.5 Mya), back when this upland area was an island, isolated from the European mainland and surrounded by the Mediterranean Sea.
As a result of this isolation, the animals that lived on Gargano – including Garganornis – were subject to an effect known as island rule. This was an evolutionary process where small animals typically grow larger and large animals shrink in size.
Garganornis was one of several animals that grew in size. It weighed roughly 22kg, making it 30% larger than today’s largest waterfowl, the mute swan.
However, unlike mute swans Garganornis couldn’t fly. Its wings were small and instead adapted for fighting.
They were robust and sported small, bony knobs on their tips that were used like maces to break the bones of other Garganornis.
Pelagornis
Pelagornis has the largest wingspan of any bird ever discovered, measuring 7.4m from wingtip to wingtip. That’s more than twice the size of a wandering albatross’, which has the largest wingspan of any extant bird.
As well as holding the record for the largest wingspan, Pelagornis is also considered the heaviest flying bird of all time. It took this particular title from Argentavis after the largest species of Pelagornis, Pelagornis sandersi, was discovered in 2014.
Unlike Argentavis, Pelagornis was a seabird that glided on ocean air currents close to the water’s surface. Some estimates suggest it was able to fly at speeds of up to 37mph and travel for several days without ever having to land.
Pelagornis lived from the Late Oligocene to the Early Pleistocene (25-2.5 Mya) and its fossils have been found all over the world, from Morocco to Antarctica.
It belongs to a group of strange, prehistoric birds known as pseudo-tooth birds. These birds didn’t have teeth, rather tooth-like projections on the margins of their bills that served a similar function and helped them to grasp slippery fish.
While they looked and behaved like today’s albatrosses, Pelagornis is more closely related to ducks and chickens.
Inkayacu
Named after the Quechua words for ‘emperor’ (inka) and ‘water’ (yacu), Inkayacu is a giant penguin that lived in what is now Peru during the Late Eocene (around 35 Mya).
In 2008, a nearly complete skeleton of an Inkayacu was found on the Pacific coast of Ica, Peru, and nicknamed ‘Pedro’. Pedro was so well preserved that several of his feathers had even been fossilised.
These feathers contain microscopic, pigment-bearing structures known as melanosomes, which have allowed researchers to work out Inkayacu’s colours. What they discovered was quite strange.
Unlike the iconic black-and-white colouration of today’s penguins, Inkayacu were grey and rusty brown. They were also a lot bigger, standing at 1.5m tall and weighing in at around 60kg. They were about the same size as an average adult woman.
Like today’s penguins, Inkayacu also hunted fish. However, its bill was a lot longer, sharper, and shaped more like a spear.
There have been some suggestions that Inkayacu weren’t able to dive quite as deep as today’s penguins. This theory is based on the fact that their melanosomes, which are thought to increase the rigidity of feathers when they’re in abundance and tightly packed, aren’t quite as numerous as they are in today’s penguins.
Dromornis
While they may look a lot like the predatory birds that once terrorised South America, Dromornis actually lived on the other side of the world. They habited Australia, from eight million years ago to 40,000 years ago.
Its bill, although huge, was blunt and it had hoof-like feet rather than talons. This suggests it was most likely a herbivore and not an apex predator like Titanis and its ‘Terror Bird’ relatives.
Still, Dromornis was a deadly bird in its own right and deserving of its nicknames, ‘Thunderbird’ and ‘Demon Duck’.
Dromornis was one of the largest birds that ever lived, dwarfed only by the elephant birds of Madagascar. The largest species of Dromornis, Dromornis stirtoni, stood 3m tall and weighed more than half-a-ton.
Like a lot of other flightless birds, it also had a tiny brain relative to its body size.
Cassowary
These birds still prowl the tropical forests of New Guinea and northeastern Australia, as they have done for the last five million years.
Take a look at a cassowary and you’d be forgiven for thinking it was a dinosaur brought back to life; after all, it has the same razor-sharp claws as Velociraptor and a peculiar head crest reminiscent of hadrosaurs.
While they technically are dinosaurs – by virtue of them being birds – cassowaries are relatively modern in terms of their evolutionary make-up.
Around 90% of a cassowary’s diet is made up of fruit, though they will sometimes eat eggs, carrion, and small animals like fish, rodents, and snakes.
This primarily herbivorous lifestyle might suggest they’re peaceful birds, but cassowaries have a reputation for being amongst the world’s most aggressive and dangerous birds.
They can kick and use their claws to slice through the flesh of other animals, sometimes nicking important veins and arteries.
There are currently two documented cases of cassowaries killing humans, which sounds like a lot, but that number is tiny compared to the number of people killed by the real deadliest living bird, the common ostrich.
These flightless giants kill an average of two to three people a year in South Africa alone.
- The biggest birds in the world (by maximum weight): Discover 10 towering, weighty avian giants
- Weirdest birds: meet 14 strange and weird wonders of the avian world
Discover more on the prehistoric wildlife