Final answer:
The saying "You can't teach an old dog new tricks" is a metaphorical statement emphasizing the difficulty of changing longstanding habits or beliefs.
Step-by-step explanation:
The expression "You can't teach an old dog new tricks" is best described as a metaphorical statement. It suggests that it is often challenging to change someone's habits or ways of thinking, especially when they have been established over a long period. While the statement could be interpreted literally to refer to the training of senior dogs, it is more commonly used to imply that older people are less likely to adopt new methods or ideas.