### Clue: Animal protection said to work when sick at heart (9)
### Answer: ARMADILLO 
 ### Explanation: Definition: Animal
 **Homophone of**(… said) "armour"(protection/tough layer or shell protecting warriors, military vehicles, or animals and plants) **plus**(to) [DO(to work/to perform) **containing**(when … at heart /… in its centre) ILL(sick)].
Defn: … having a tough protective shell.