…Even in the best books on heraldry, natural history, and in other illustrated publications, the elephant is rarely to be seen correctly delineated. A peculiarity in his formation is that the hind legs bend in the same manner as the fore legs, so that, unlike other quadrupeds, it can kneel and rest on its four knees, whereas it is usually depicted with the hind legs to bend in the same way as those of the horse or the cow.

From Fictitious and Symbolic Creatures in Art by John Vinycomb, p10