There is another, most interesting, tail condition which I have seen only three examples of. I suspect that the cause is that the developing tail is injured, probably while the bones are still cartilaginous in the pouch, giving rise in the adult to either a knob tail, with the tail vertebrae coiled into a small ball, or a circular tail, which looks astonishing. The three examples all survived well into adulthood (until two were killed by cars) and seemed to demonstrate that some of the popular ideas about the purpose of the kangaroo tail are slightly exaggerated. An effectively tailless kangaroo can still hop and keep up with the mob. But of course it cant punt when they are grazing. Instead it either briefly rests its weight on its hands while moving both feet forward together, or it breaks the popular rule about kangaroo locomotion by shuffling each foot forward independently.
I am an ecologist and have worked with many vets, often straining to learn the terminology.
Veterinarian. There is also an EG juvenile with a floppy tail, as if the ligaments between the tail vertebrae are too elastic. He still gets around okay. Occasionally see older males with tail joint arthritides.
Hi Frecko, I too have been fascinated by the pathologies I have encountered in kangaroos, mostly hopping-related or tail-related. You have an unusual familiarity with the anatomical terms relating to locomotion. Are you a zoologist /veterinarian /pathologist/ or horse expert perhaps?
On further examination of the closer image, it could also just be a rupture of the right calcaneal tendon (there is no tautness to it). This would also explain the poor weight-bearing characteristics of that leg in the further image.
