It really doesn't make any sense to me grammatically if that's the case. Do you have an original, printed copy? We've had the case here before that someone turned out to be working off a digitised version with errors in. I found a list of
comparative translations which includes:
それはボアという大きなヘビが動物を呑み込もうとしているところの絵だった。
(池澤夏樹訳)