T. K. Arispe

 I was listening to a podcast on phorusracids and it just made me want to draw the kelenken from a novel I've been working on. They are literally the species Kelenken; I just lifted them wholesale from the fossil record and plunked them into my fantasy world. (Okay, I also made them slightly larger and more robust so they'd be rideable.)

On the vast steppe of the Sogen, the Plainsmen have learned to ride kelenken and use them as their main mode of transport (making them analogous to horses). By the time the novel takes place, the kelenken have become an integral part of Plainsman culture, especially because they are also extremely effective combat animals.

Plainsmen breed kelenken and give chicks to their children, with the animal reaching maturity as the child learns to ride. Kelenken have a lifespan of seventy years on average, so a kelenken and its rider develop a close, lifelong bond.

Kelenken are extremely intelligent and able to be trained to understand commands. However, in the novel, Arun explains that kelenken are not tame nor domesticated--they choose to live and work with the Plainsmen because the Plainsmen offer them safety, food security, and mental stimulation. When not being ridden, kelenken roam the plains outside of camps, doing their own hunting, but each rider and kelenken develop a unique whistle that they can use to call for one another across the steppes.

Over the course of the novel, Arun's kelenken Vy develops a close bond with Liu, and although as a Plainswoman by marriage, Liu is entitled to her own kelenken, she prefers riding Vy (and I think he prefers that too).

Also, if you're thinking Vy looks way too tall for Liu, you're right. Liu's people are rather petite and the Plainsmen are much taller and easily capable of mounting kelenken. Vy just sits down when Liu needs to mount him. He's adjusted quite well to having a non-Plainsman in the family.