Possible Clues:

• Animal has to run off after much smaller one
• Open late, potentially making a fast buck, perhaps?
• A graceful gazelle from Africa
• Retired European invested in stake for animal
• Duiker or dik-dik
• Hoofed beast
• Run putting bet on fast runner
• A lone pet as a ruminant
• Mount up to run after animals
• Deer's playmate