JAN. 6: Marta stretches and stays close to her twin Amur tiger cubs Viktor and Talya as they make their media debut at the Toledo (Ohio) Zoo. The cubs were born Sept. 26. This is the second generation of the endangered Amur tigers to be born at the zoo. Marta was born in Toledo in 2003.

JAN. 11: A frog sits on a U.S. dime in this photo taken by Louisiana State University herpetologist Christopher Austin near the Amau River in Papua, New Guinea, in August 2009. The species was claimed as the world’s smallest vertebrate on Jan. 11. Austin was studying the area’s rich biodiversity when he and graduate student Eric Rittmeyer found the frog, which they named Paedophyryne amauensis for the village of Amau. The frog out-tinied a Sumatran carp identified in 2006. Its discovery was reported in the journal PLoS ONE.