Actually, I read an article by Nosson Slifkin about it.
His position is that:
A. Elephants cannot jump.
B. Tosfos had never seen an elephant and had only seen pictures, which usually depicted elephants with bent knees like any other animal which indicates they can jump.
C. It is not a problem to say tosfos was mistaken since the tosfos serves a purpose in any event by telling us that you can do hagbaha by making the animal jump.
I am skeptical of his arguments. Tosfos was only willing to say that you can do hagbaha by making it jump since the gemara said you could use “pili” to acquire an elephant.
It therefore comes out that the halacha should really be that you cannot use jumping.
It seems to me that if tosfos was wrong, the halacha is also wrong.
I have no idea what the answer is.