Probably it is the largest hunting bird in the world, weighing almost six kilos. Their favorite preys are monkeys, but, they also eat sloths and other small mammals. With such references it is easy to understand why it is considered the most ferocious rapacious of all birds that inhabit the American continent. The Harpy Eagle is at the top of the food chain.  The Harpy Eagle feeds on at least 19 animal species, the large majority are arborious that live of top of trees.

These jungle eagles are big and females are larger that males.  Females measure more than one meter long and can weigh 18 pounds, while males do not even reach one meter long and weigh approximately 11 pounds. They reach a flight speed of  200 km/hour. The back of the body and wings are black, as well as the breast.  The tail is black with three grey bands. Below the wings the plumage is white; the flight plumage is white spotted with black.  The iris is orange, the beak is black, the tarsus, yellow and the talons are black.

Harpy Eagles can measure almost two meters with the wings extended. They are silent and go by inadvertedly in spite of their size. They have short and rounded wings with secondary very wide remiges. The tarsus have thick and long nails (7 cm in the posterior finger).

It seems that the occipital crest is used to cammouflage the silhouette in the foliage. The facial disk and the crest plumage also help the eagle to communicate intentions and express possible threats.

Usually, Harpy Eagles are quiet and tranquil birds as they must save their energy. When they are after their prey, they do so with short speed explosions. The females are larger and look for heavier prey. Males are quicker and faster. The contemplation of a Harpy is a spectacle few people have enjoyed, due to the fact that, opposite to the great majority of diurnal rapacious, they do not go out frequently planing on top of the Jungle, due to something paradox called the Invisible Eagle.
When the nest is ready, the female lays 2 eggs with an interval of one day. She sits on them  for 55 days. During this period the male brings food, as well as in the first days after the birth of the pigeon, and, after that, it does so sporadically. Finally, when the female can leave the pigeon alone in the next, she starts feeding it. One of the pigeons is born 56 days later, and, the other one is abandoned to his own device.