Is the Greater Rhea kneeling – or reverse kneeling?

Large birds, such as herons, storks, cranes, maribou, rhea, ostriches, and emus, look a bit odd when they have their large legs extended in front of them.

The long bone from the foot digits to the first joint is the tarsometatarsus bone. This bone is only found in the lower leg of birds. Humans don’t have this bone, nor does cats, dogs, or other mammals, or reptiles, or any other animals. 

All birds have this bone, but it is most noticeable in long-legged birds.

When the Greater Rhea looks like it is sitting, it is really standing on its tarsometatarsi (the plural of tarsometatarsus). It looks like its knees bend to allow the tarsometarsi to extend in front of its body. 

Actually, what people are seeing is the ankle close to the ground, not the knee. The knee is further up the leg, often hidden by the bird’s feathers. 

Location of photographs: Paris Zoo, France

Photographer: Martina Nicolls

Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM