Reader, here is an incomplete list of things you should not try with elephants: a memory contest, jump rope and castration. See, in addition to having uncanny recall and a firm relationship with ...

Scientists have long wondered what the earliest mammals’ balls were like. After all, a few species today live with theirs swaddled safely up by the kidneys, like elephants do. Most other mammals drop ...

Seeking an answer, a useful first step is to trace the evolution of descended testes. Testes remain high up in the abdomen in egg-laying mammals (monotremes), but descend in all marsupials, ...

Most male mammals carry precious cargo in an awfully precarious package. External testicles—which swing delicately outside the abdominal cavity in an exposed, thin-skinned sack—are sensitive, finicky, ...

The scrotum is a mystery. Why do most male mammals have their reproductive glands so vulnerably located in a sack of skin and muscle outside the body? According to new research, the answer might be ...

My 2013 book, How We Do It, addressed an enduring mystery in mammal reproduction: “It is often claimed that the word ‘testify’ comes from an ancient Roman custom in which a man would clutch his testes ...