Animals can't tell us how they're feeling. But they can communicate their needs through a variety of ways that can be observed and measured.
We can assess an animal's physical and psychological state by monitoring behavior, body condition and hormone levels, and that information helps us improve an animal's quality of life.
Hormones are chemical messengers that trigger a wide variety of processes in the body. Using non-invasive techniques to sample urine and feces, Oregon Zoo researchers track the levels of 'stress hormones' – such as glucocorticoids – and reproductive hormones over time to reveal how an animal is responding to its surroundings and activities.
Because keepers have the most personal connection with individual animals, they are invaluable in assessing and evaluating the animals' welfare and well being on a daily basis. Keepers, researchers and trained volunteer observers track levels of behavioral activity, self-maintenance behaviors such as self-grooming (mammals) or preening (birds), social interactions and other indications that an animal is thriving. Data is collected using tools such as Welfare Trak and Zoo Monitor.
The philosophy of animal welfare doesn't only apply to animals in our direct care. Research keeps revealing new connections between welfare and field conservation.