Final answer:
When food is scarce, mice will intensify their search for food inside the restaurant and may leave the premises to find alternative food sources. Increased competition could also lead to more aggressive behavior among mice.
Step-by-step explanation:
When food becomes unavailable to mice that have infested a restaurant, the expected behavioral change might be an increase in their scavenging efforts and thorough search for hidden food within the premises. If unable to locate sufficient food supply, mice are likely to leave the premises in search of alternative food sources. This response is typical as survival instincts would drive them to find a new habitat with adequate food. While there might also be increased aggression among the population due to stress and competition for limited resources, the primary concern for the mice will be to fulfill their basic need for sustenance. Thus, a combination of both scavenging and eventually migrating could be expected.