A swath of Congo rainforest larger than the state of Massachusetts will be designated as a nature reserve in a collaborative effort between American and Congolese environmental groups and agencies. Advocates hope the reserve will be a significant step toward protecting the endangered bonobo, one of humans’ closest ape relations. Bonobos, which live only in the Congo, are often targeted by poachers. They are also the only primates other than humans known to have sex not just for procreation, but for pleasure. And if that’s not worth preserving, we don’t know what is.