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This is HUGE! Top 10 Largest Birds in the World

Top 10 Largest Birds in the World
While the ostrich is well-known as one of the largest birds in the world, there are many others who deserve a shout. Here is a list of the largest birds in the world, flying as well as flightless.
Tanmay Tikekar
Last Updated: Mar 8, 2018
Blast from the Past
Argentavis magnificens, an extinct bird known only through fossils, is believed to have been the largest flying bird known to man. It had a wing span of up to 7 meters, almost twice that of the largest of extant birds, and weighed more than 50-60 kg, which would only be bettered by the ostrich out of all extant birds.
The last living relatives of the dinosaurs, more often than not, live up to the famed proportions of their almost-mythic ancestors. Who would think of a gigantic sauropod or a terrifying tyrannosaur when they see a sparrow? Who would be reminded of the triceratops by seeing a crow?

There are some birds, though, that, while not quite reaching the levels of dinosaurs, are giants in their own rights. Ostriches, for example, would comprehensively dwarf most humans. Moas and elephant birds, now extinct, would have dwarfed even ostriches!

Here's a list of the 10 largest birds that can fly as well as those that can not fly.
The Winged Giants
This is a list of the top 10 heaviest birds alive today; weight is the criterion normally used to list the 'largest' birds. Most of these are too large to fly, and many even lack the skeletal structures (a keel on the breastbone) necessary for flight.
The ostrich, Struthio camelus, is the heaviest and tallest bird alive today.
► Average weight: 230 lb (104 kg)
► Maximum recorded weight: 346 lb (156.8 kg)
► Average height (length): 6.9 feet (2.1 m)
Southern Cassowary
Southern cassowary
The southern cassowary, Casuarius casuarius, is the largest bird in the continent of Australia.
► Average weight: 99 lb (45 kg)
► Maximum recorded weight: 190 lb (85 kg)
► Average height (length): 5.1 feet (1.55 m)
Northern Cassowary
Northern cassowary
The northern cassowary, Casuarius unappendiculatus, is the heaviest bird native to Asia.
► Average weight: 97 lb (44 kg)
► Maximum recorded weight: 170 lb (75 kg)
► Average height (length): 4.9 feet (1.49 m)
The emu: Dromaius novaehollandiae
► Average weight: 73 lb (33 kg)
► Maximum recorded weight: 150 lb (70 kg)
► Average height (length): 5.0 feet (1.5 m)
Emperor Penguin
Emperor penguin
The emperor penguin, Aptenodytes forsteri, is the largest species of penguins.
► Average weight: 69 lb (31.5 kg)
► Maximum recorded weight: 100 lb (46 kg)
► Average height (length): 3.7 feet (1.14 m)
Greater Rhea
Greater rhea
The greater rhea, Rhea americana, is the heaviest bird in the New World.
► Average weight: 51 lb (23 kg)
► Maximum recorded weight: 88 lb (40 kg)
► Average height (length): 4.4 feet (1.34 m)
Dwarf Cassowary
Dwarf cassowary
The dwarf cassowary: Casuarius bennetti
► Average weight: 43 lb (19.7 kg)
► Maximum recorded weight: 75 lb (34 kg)
► Average height (length): 3.4 feet (1.05 m)
Lesser Rhea
Lesser rhea
The lesser rhea: Rhea pennata
► Average weight: 43 lb (19.7 kg)
► Maximum recorded weight: 63 lb (28.6 kg)
► Average height (length): 3.2 feet (0.96 m)
King Penguin
King penguin
The king penguin: Aptenodytes patagonicus
► Average weight: 30 lb (13.6 kg)
► Maximum recorded weight: 44 lb (20 kg)
► Average height (length): 3 feet (0.92 m)
Dalmatian Pelican*
Dalmatian pelican
The dalmatian pelican, Pelicanus crispus, is one of the heaviest as well as tallest flying birds
► Average weight: 26.4 lb (12 kg)
► Maximum recorded weight: 33 lb (15 kg)
► Average height (length): 5.6 feet (1.7 m)
* Individuals of large swans or bustards, particularly male kori bustards, may be heavier than dalmatian pelicans, but on average the latter is heavier. Male kori bustards can reach weights of 44 lb (20 kg), but the females are significantly less massive.

As you can see, most of these birds can't fly. The dalmatian pelican, in fact, may be the heaviest flying bird when both sexes are taken into consideration. Losing the ability to fly allowed these terrestrial or aquatic (penguins) birds to gain solid, heavier bones instead of the hollow bones seen in flying birds.

Here are several other 'largest' birds according to different definitions of 'largest'.
Sarus Crane
Sarus Crane
► The aforementioned dalmatian pelican is a close contender for the title of the tallest flying bird in the world. However, the Sarus crane, which can grow to a height of almost 2 meters, takes the crown in that category.
Wandering albatross
Wandering Albatross
► The dalmatian pelican, in general one of the largest creatures to fly, also gets a podium place in the standings for the longest wingspan. However, the wandering albatross, a bird that spends virtually its entire life airborne, has wings that can extend up to 3.5 meters that give it the title.
Andean condor
Andean Condor
► If both weight and wingspan were taken into consideration, the dalmatian pelican is arguably the largest flying creature alive today. But it would be followed closely by the Andean condor, which has a wingspan larger than the pelican, and is only a couple of kilos lighter on average.
These were the largest birds alive today. However, these giants are nothing compared to their extinct nonflying ancestors, which included the elephant bird (Aepyornis maximus), weighing 880 lb and standing 3 meters tall, and the moa (Dinornis robustus), which was even taller, but weighed "only" 500 lb. Good thing, these 'bird-zillas' are gone from the face of the Earth, then!