What is the primary purpose of the passage?

In Massachusetts, black bears have expanded from a small isolated population in the Berkshire Mountains to an estimated 4,500 bears across the state. Massachusetts is the third-most densely populated state in the nation, and human development is expanding, sometimes putting bears and people in close proximity to one another. Why would black bears use populated areas? They are omnivorous opportunists with a good sense of smell, and can sniff out calorie-rich foods that often are found in developed areas, such as bird seed, pet food, garbage and even agricultural crops. These foods may be especially attractive to bears before and after hibernation, when the animals are living solely off stored body fat. Before hibernation in the fall, bears enter a metabolic state called hyperphagia – literally, excessive eating – in which they consume 15,000 to 20,000 calories a day. That’s roughly equivalent to eight large cheese pizzas or five gallons of chocolate ice cream. During hibernation bears can lose up to one-third of their body weight. And after they emerge from their dens in springtime, natural foods are typically scarce until plants start to leaf out and flower. Black bears’ energy requirements during these phases can drive their behavior. After examining the data from 76 black bear GPS collars across central and western Massachusetts it was seen that black bear moved around more in daytime than at night, and avoided humans and developed areas during the day. However, we also found that in spring and fall, when the bears had increased caloric demands, they altered their natural daily rhythms to move through human-developed areas at night.