The Lion represents the British Empire, proud and fierce, and King of th Jungle. Never mind that the lion is usually a lazy old Lothario, with th lionesses doing the actual hunting.... that's not the intended message.
The Crocodile represents, the old African order, almost dinosaur-like in it's slow moving** and vicious nature.
The triumph of Lion over Crocodile clearly represent Imperial Confidence.
...except, that pose by the crocodile is rather suggestive. Maybe it's not a fight to the death. Maybe it's not British Empire defeating the old order. Maybe the sculptor's message is "Africa has been well and truly flicked by the British."
** - Bonus. Slow moving crocodile? Yeah, Sure.