Pegging, defined by Dan Savage as the sexual practice in which a woman penetrates a man's anus with a strap-on dildo, is taboo. It's an eventuality surrounded by incredulity. Many gay men look suspiciously -or with hope- at straight men who like to be penetrated.
What two characteristics make mammals unique from other vertebrates? Mammals are unlike other vertebrates in two distinct ways. First,  all mammals have hair, unlike other vertebrates. Also, female  mammals carry their offspring to full term â¦in the uterus, whereas  most other vertebrates lay eggs.
The basic body type is a four-legged land-borne animal, but some mammals are adapted for life at sea, in the air, in the trees, or on two legs. The largest group of mammals, the placentals, have a placenta, which enables feeding the fetus during gestation. Middle ear-In crown-group mammals, sound is carried from the eardrum by a chain of three bones, the malleus, the incus, and the stapes. 2  Ancestrally, the malleus and the incus are derived from the articular and the quadrate bones that constituted the jaw joint of early therapsids.