Possible Clues:

• Tom starts in sport with Manx cat, an unusual creature
• Semi-aquatic egg-laying mammal
• *Egg-laying mammal
• Australian egg-layer
• Aussie creature
• Exotic animal supply at dances
• Australian egg-producer provides a supply that's irregular - about time!
• Duck-billed Australian mammal
• The duck you'll get billed for may not be a bird
• Supply different cage for a time for unusual mammal