By David Farrier
Zoophilia comes from the Greek words for "animal" and "friendship" or "love".
Now an American man has written a book about it - a first-hand account.
We all love dolphins, from Flipper to Opo – they are a friendly face to the human race.
But Malcolm Brenner, had a friendlier relationship than most.
In 1970, the photographer embarked on a 9 month sexual relationship with Ruby, a captive female dolphin.
He has now written a book about the experience called Wet Goddess.
Mr Brenner spoke to Nightline from his Florida home. Below is the transcript of our conversation.
DF: Thanks for your time. How did this whole thing start?
MB: She began raking her teeth lightly against my arms and legs which was indescribably erotic. Some might find it frightening, I found it erotic.
DF: Now in your book, you talk about how that led on to you two having sex. A lot of people would say that's wrong, what's right in your mind about what you did?
MB: What was right with it is that the dolphin initiated the whole sexual thing. As I mentioned, she was in isolation - she'd be using me to satisfy her sexual needs.
The relationship lasted nine months. When Mr Brenner went to college - Ruby passed away - possibly due to a broken heart.
"I'd warn anyone who's in a relationship with a dolphin. You have to plan an exit strategy," says Mr Brenner.
Mr Brenner believes around 15 percent of the world's population has had sexual contact with an animal.
"If you believe the statistics, something like one in every six men and one in seven women has had sexual contact with an animal," he says.
"How many of those involve dolphins I do not know."
Mr Brenner's book, Wet Goddess, is currently rated 5 stars out of 5 on Amazon.com.