Which Are Top-5 Heaviest Living Birds in the World?

The birds display impressive variety when it comes to their size, appearance and natural habitats. Even though there are many small birds that can fly, the largest existing birds have gone a different way of evolution. Most of the birds that weigh the most are flightless birds with good legs and body structure suitable for life on land. The ostrich is considered to be the heaviest living bird with really big males weighing up to 156 kg. Other gigantic bird species include the southern cassowary, emu, emperor penguin and greater rhea.

Top 5 Heaviest Living Birds on Earth

Rank	Bird Name	Scientific Name	Maximum Weight	Important Feature
1	Ostrich	Struthio camelus	Up to 156 kg	Heaviest living bird in the world
2	Southern Cassowary	Casuarius casuarius	Up to 85 kg	Large flightless forest bird
3	Emu	Dromaius novaehollandiae	Up to 55-60 kg	The largest bird in Australia
4	Emperor Penguin	Aptenodytes forsteri	Up to 45 kg	The biggest penguin species
5	Greater Rhea	Rhea americana	Up to 40 kg	The largest living bird in the South America

Here Are Top-5 Heaviest Living Bird on Earth

1. Ostrich – Up to 156 kg

Ostrich (Struthio camelus) is the heaviest extant bird on Earth. A large male may weigh up to 156 kg and have a height of almost 2.75 m.

Despite being flightless, the ostrich has strong legs that are designed for running. It may reach speeds of up to 70 kmph and thus become the fastest bird on Earth.

2. Southern Cassowary – Up to 85 kg

The southern cassowary (Casuarius casuarius) lives in the rainforests of northern-eastern Australia and New Guinea. The females are larger and usually reach the weight of approximately 80-85 kg, whereas males are relatively smaller.

This species of flightless bird is recognizable by the black color of its feathers, blue and red neck, and a casque on its head. Moreover, it helps to disseminate the seeds of rainforest ecosystem.

3. Emu – Up to 55-60 kg

Emu (Dromaius novaehollandiae) is the largest bird in Australia and one of the largest birds in the world. Females are heavier than males and usually have the weight of 50-60 kg.

An adult emu may be as high as 1.75 m and cannot fly. Nevertheless, due to its long legs, the emu is able to3. Emu – 55-60 kg

This flightless Australian bird, Dromaius novaehollandiae, is Australia’s biggest bird and one of the world’s biggest extant birds. Females are usually a little bit heavier than males, and usually, an adult emu weighs from 50 to 60 kg.

Emus may be up to 1.75 meters tall, and they cannot fly, but their big long legs make them capable of running at a speed of up to 50 km/h.

4. Emperor Penguin – Up to 45 kg

This penguin Aptenodytes forsteri is the largest species of penguin, and it proves that being a big heavy bird does not necessarily mean being a land animal.

Emperor penguins live in Antarctica, and they may weigh up to 45 kg. The weight of emperor penguins varies considerably depending on the period of breeding and fasting.

5. Greater Rhea – Up to 40kg

Greater rhea (Rhea americana) is common in some regions of South America and is the largest bird found on the continent.

These birds weigh between 15 to 30 kg, although males can be larger with weights close to 40 kg. Just like ostriches and emus, greater rheas belong to the family of ratites and they make up most of the flightless birds.

The wings of these birds are mainly used for balance and steering when running and not for flying.

Why Are Most of the Heaviest Birds Flightless?

The heaviest birds alive usually have physical features that do not support their ability to fly for a long time. Unlike flying birds, they have not adapted their bodies to become light and develop powerful flight muscles; but instead, they have developed sturdy legs and heavy bodies that facilitate their movements.

In addition, their legs are also long to enable them to run fast and cover long distances.