Hamerkop standing on a hippo, Mana Pools National Park, Zimbabwe

© David Fettes/Getty Image

International Day of Friendship

Who better to embody the spirit of International Friendship Day than these two buddies of different species? Here in Zimbabwe's Mana Pools National Park, the hamerkop, a wading bird, catches a ride from a hippo into deeper waters, where it can access fish and insects it otherwise couldn’t reach.

In 2011, the United Nations declared July 30 as International Friendship Day, but individual countries have long set aside various dates to celebrate that special bond between friends. And how does one celebrate this day? It can be as simple as letting your pals know that you appreciate their friendship, no matter where they happen to be, either physically or in the biological taxonomy.