Portrait by Jillian Tam. A male Western Lowland Gorilla sits in his exhibit at the Franklin Park Zoo on Franklin Street in Boston, Ma., on Monday, November 23, 2015.
Free Selection by Cara Aguado. A Cotton-Top Tamarin sits on a branch in its cage at the Cape May County Park and Zoo on Friday, November 27, 2015.
Birds by Cara Aguado. Two parrots hang on their cage as one cleans the other at the Cape May County Park & Zoo on Friday, November 27, 2015. Nearly all social birds demonstrate peer grooming and many birds solidify or reinforce pair bonds, family bonds, or flock bonds by grooming one another.
Wing by Erin Onushco. A bat hangs upside down in it’s cage at the Philadelphia Zoo on November 24, 2015.
Bird by Erin Onushco. Toucan sits on a branch at the World of Birds at the Bronx Zoo on Friday, November 27, 2015.
Bird by Nicholas Gales. Male Northern Pintail at the McNeil Avian Center in the Philadelphia Zoo in Philadelphia, Pa. on December 3, 2015. Northern Pintail’s gender can be identified simply by the color on its wing: red for male, green for female.
