Related Clues:

• Horse with stamina
• One that lasts the course
• Long-distance runner, rather than sprinter
• One that can last the course
• Horse that can go the distance
• Obedient dog
• Type of cattle dog
• Blue ___ (herding dog)
• A river, on reflection, is a river
• Annoyed exclamation raised about the old person hanging on
• Guy about to make a comeback, a tenacious sort
• Tenacious steed brilliant when carrying you
• "He fetched him such a –– as gave him something else to think about" (Rolf Boldrewood, Robbery under Arms)
• One likely to carry on being stumped by philosopher
• One with lasting qualities