Why it matters: It's the first known animal to test positive for the virus in the United States. The tiger is believed to have contracted the virus from an asymptomatic zookeeper.
A new scientific review published in Nature found that marine life has been rebounding in recent years, thanks to conservation efforts, and the oceans could be fully restored by midcentury.
Why it matters: The oceans cover almost two-thirds of the Earth's surface, yet for too long we've treated the waters as a dumping ground.