It's only human to want to take credit for every single concept in the known universe, but there are a number of things that we're simply not responsible for. For example, the concept of trading sex for favors seems to be a totally human one, but as it turns out, members of the animal and insect kingdom have been doing this for eons.
According to a new article on io9 (link below) there are at least ten different species who practice this bartering system, and here are a few of the choicest examples.
Adélie Penguins are not Child-Friendly
This is something you didn't see in Happy Feet. Remember those penguins that ran around collecting rocks to make nests in order to attract a mate? Well, when the happy couple finally gets together, they build their nest up together. Both the female and the male go out to discover or steal rocks. Ah, but the female has a trick she can pull if her mate isn't watching. If she sees another male with a particularly fine rock in his beak, she'll have sex with him in exchange for the rock and then happily go back to the nest. Her official mate is none the wiser.
If only someone could enlist Morgan Freeman's help in making this sound less horrific.
Crickets Need to Bring a Big Gift if They Want to Reproduce
A male decorated cricket will give a female a gift while he tries to inseminate her. The mating process involves attaching a sac of sperm to her body. If she's done eating before he's finished, she'll reach back, grab the sac, and eat it as well. And there goes his chance to spread his genes. So not only does he have to bring her a present, whatever present he gives her has to be big enough that she's full when she feels ready to reproduce.
I've seen plenty of males attach a sac of sperm to a female's body. One of the hazards of my profession.
Dolphins Will Pimp Their Mates
Most people reading this will know already that dolphins are evil. They engage in infanticide and recreational porpoise murder. When a female pairs off with a male, sometimes another male will join them — with the consent of the existing male. Pairs of male dolphins will separate a female from the herd and guard her from other males. They will both have sex with her, dividing their chances of having any offspring but greatly increasing their chances of success compared to the free-for-all that would happen if the female were with the rest of the herd.
I haven't seen a dolphin orgy since Marino retired.
Capuchins' Interests Include Both Sex and Porn
When researchers gave capuchin monkeys tokens that could be exchanged for snacks, an economy sprang up. Not only would these monkeys have sex in exchange for tokens, they would also trade tokens for extended looks at pictures of other (and presumably hot) monkeys. It seems capuchins like to fantasize.
So just remember guys, you're not sex addicts, you're simply Capuchins.
Via io9