Are Human Beings The Only Animal That Can Mates Face-to-Face?

Whales, dolphins and sea otters all mate belly-to-belly. Chimps and orang-utans normally mate belly-to-back, but it's possible they may mate face to face now and then - bonobos have been observed doing so. 

Porcupines mate belly-to-back, despite the common belief that their spines make this impossible - in fact, the female flattens her spines and raises her tail, enabling the male to mount her from behind. Confusion may also come from the fact that, prior to mating, they stand on their hind legs, facing each other, while the male sprays the female with urine - this is part of the courtship ritual, but is not mating.