The 10 Biggest Birds In The World | Bird Spot

Many of the birds we encounter in our day-to-day lives are tiny, often weighing just a few grams. But some species of bird are surprisingly large, reaching heights even greater than the tallest humans.

Most of the largest birds in the world are flightless which allows them to have denser bones and heavier bodies. They have evolved other traits to allow them to escape predators such as strong, powerful leg muscles which means they can run at high speeds.

None of the largest living birds are anywhere near the size of the elephant birds though, members of an extinct family of ratites. The largest of these, Vorombe titan, weighed over 700 kg and stood about 3 m tall making it the largest bird to ever have lived.

01

Ostriches

Ostriches (Struthio camelus) are the largest living birds in the world, with an average mass of 104 kg and average length of 210 cm. They lay the largest eggs and hold the record for the fastest land speed of any bird, reaching speeds of 70 kmph. It is also thought that ostriches have the largest eyes of any land vertebrate at 50 mm in diameter.

Ostriches are native to Africa but are farmed all over the world, particularly for their feathers, skin which is used in leather products, and meat. In 2014, the Somali ostrich (Struthio molybdophanes) was recognized as a distinct species.

02

Cassowaries

The southern cassowary (Casuarius casuarius), also known as the double-wattled cassowary, Australian cassowary or two-wattled cassowary have an average weight of 45 kg and are around 155 cm long. Southern cassowaries are found in north-eastern Australia, Indonesia and New Guinea.

Northern cassowaries (Casuarius unappendiculatus) also known as the single (one)-wattled cassowary or golden-necked cassowary, are slightly smaller with an average weight of 44 kg and average length of 149 cm. They are endemic to northern New Guinea.

03

Emus

Endemic to Australia, emus (Dromaius novaehollandiae) are the second tallest living birds in the world that can reach up to 190 cm tall. They weigh an average of 33 kg. Female emus are usually slightly larger than the males and have significantly wider rumps.

Emus have evolved to run fast and despite being flightless they have vestigial wings, which they flap when they run to stabilise themselves. They only have 3 toes and a reduced number of bones and foot muscles. Emus are the only birds with gastrocnemius muscles found in the back of the lower legs.

04

Penguins

Emperor penguins (Aptenodytes forsteri) are endemic to Antarctica and are the tallest and heaviest of all living penguins weighing an average of 31.5 kg and measuring 114 cm in height. During breeding season male Emperor penguins lose up to 15 kg as they do not eat anything while they protect their eggs from extreme cold for more than 2 months. Like all penguins, Emperor penguins are flightless but they have adapted to the harsh conditions of their environment which is the coldest for any breeding bird. Feathers provide up to 90% of their insulation and they are able to thermoregulate their core body temperature without altering their metabolisms.

King penguins (Aptenodytes patagonicus) weigh 13.6 kg on average and are 92 cm in length. They breed on Subantarctic islands, as well as Tierra del Fuego, the Falkland Islands, and other temperate islands of the region.

05

Rheas

Greater rheas (Rhea americana) are flightless birds native to South America. They are also known as grey, common, or American rheas. Greater rheas have an average mass of 23 kg and an average length of 134 cm. A small population of greater rheas has established itself in Germany. One male and five females escaped from a farm in August 2000. They survived the winter and began breeding. It is estimated that there is now a population of about 250 birds which are considered domestic and therefore protected from hunting.

Lesser rheas (Rhea pennata), also known as Darwin’s rhea, are found in Altiplano and Patagonia in South America. It weighs on average 13.5 kg and has an average length of 96 cm.