听力材料：
Narrator:Listen to part of a lecture in a biology class.
Professor: Scientists have noticed that female animals that are mothers are better at finding food than those that don’t have young. They think it’s because the female’s mental abilities improved when they become mothers. In particular, research has shown that the mother’s memory actually improved, which makes her better at caring for her young, better at finding food for her young. What’s the evidence for this? Well, scientists did an experiments with mother rats and rats that weren’t mothers—non-mother rats, and they built a maze. The object was the rats find their way through the network of paths in order to get to the food at the end. The rats had to explore it because only one path of it led to the food. And what the scientists were interested in was the speed. They tested the time it took the rats to find the food. And it turns out that mother rats were faster and spent less time finding their way through the maze than non-mother rats. Mother rats were much better at remembering which places in the maze they had already checked. They didn’t waste time repeating the same wrong turn, or returning to the same dead end over and over.
What did scientists learn from this? Well, they concluded that these enhanced mental abilities help the mothers care for her young in the wild. With an improved memory, a mother is faster at finding food in the woods, fields, wherever she and her young are living, because she can remember where the best places are to look, so she will spend less time searching which is good for the survival of her young because it means that she will be able to get to her nest faster to protect her young, which are vulnerable to attack by professors when she’s away.
Question：
The professor discusses an experiment with mother rats. Using the experiment, explain what scientists have learned about the mental abilities of some mother animals.
