Pandas will travel between different habitats if they need to, so they can get the nutrients that they need and to balance their diet for reproduction. For six years, scientists studied six pandas tagged with GPS collars at the Foping Reserve in the Qinling Mountains. They took note of their foraging and mating habits and analyzed samples of their food and feces. The pandas would move from the valleys into the Qinling Mountains and would only return to the valleys in autumn. During the summer months bamboo shoots rich in protein are only available at higher altitudes which causes low calcium rates in the pandas and during breeding season the pandas would trek back down to eat bamboo leaves rich in calcium.