But this year they say they have fewer resources to deal with the annual trend.
The Western Pennsylvania Humane Society says adoptions are down by about 100 compared to last year, so their facilities are largely full heading into the summer.
Society officials say adoptions are down because of rising fuel and food costs. They say there are also people who adopt animals but then can't deal with the costs associated with caring for a pet, so they leave them at the shelter.
Summer is also a time when more dogs get lost and are dropped off at shelters.
