East-Germanic languages, as e.g. the Gothic language, were spoken in todays Poland between the rivers Oder and Vistula and are a different (and extinct) branch of the Germanic languages than West-Germanic (German, Dutch, Frisian, English) or North-Germanic (Danish, Swedish, Norwegian, Icelandic, Faroese).
This applies to Czech (velbloud) as well. The thing is, we already call hippos elephants. The Czech word "hroch" is related to the chess piece "rook" in English. What about the Czech name for elephant then? It's "slon" and it means lion.