First, lets' be clear about this subject matter. For all of you bikers who ended up on this chapter thinking the "estrous cycle" has to do with Harley Davidsons, you have come to the wrong place. This is all about the estrous cycle that governs sexual desire as it relates to procreation.

Dating and understanding sexual desire a.k.a libido will help both men and women to find a compatible mate. Here you will find some information that explains why your date (or for that matter you spouse) is not always in the mood.

Humans have a number of vestigial parts, mutations and nuances found in early man (gender neutral) and found even more commonly in other lower animals. For example, today we have fewer people born with wisdom teeth as their need to chomp on gritty food diminished over eons with the development of chocolate pudding and Dairy Queen. We do not have a tail like our monkey brethren since the advent of the wheel and the subsequent invention of the bicycle made swinging through the trees an outdated form of transportation. And most certainly we have lost the need for a multitude of functional designs still present in birds, apes and a host of lower creatures. Even the advantages of the species we call sharks was no longer needed once we created law schools and lawyers.

One primitive function said to be lost to humans in the course of evolution is called the estrous cycle. Estrous is defined as a recurring cycle of sexual receptivity and fertility in many female mammals. We often use the term "heat" when referring to animals when they are really in to sexual desire and activity. Who hasn't heard the neighbor’s cat roaming the neighborhood late at night squealing and screeching while engaging in sex with the neighborhood Tom cats that have waited patiently for this moment? Horses, chickens, dogs and a multitude of lower animals experience estrous. It's God's
way of making sure each species propagates and continues their lineage.

Biologists consider estrous to be something not experienced by humans. I take issue with that conventional line of thought. This theory of mine came about when I was on vacation and heard the lady in the adjacent room squealing and screeching much like my
neighbor's cat. Realistically speaking most guys have either heard similar sounds or actually experienced them in their own beds at night.

So, could female humans experience an estrous cycle where they are more receptive to sexual activities? Well they sure can experience the opposite phenomenon - something
we call a premenstrual cycle - a time in which there is a whole lot of squealing and screeching that sends the opposite message, that being, "Oh, you want sex? Well, not tonight, jerko!"

Logically speaking, why couldn’t women have the opposite, complimentary cycle? A cycle of wanting sex more than usual (estrous). Most every man and woman alike, knows that there are certain times that women are more amorous and "in the mood," and there are other times that women are not "in the mood.” While you can't generalize, this phenomenon is usually related to an actual cycle that corresponds to the menstrual cycle. This means it's a hormone based phenomenon - a biological process. Even though this is not a very new observation, scientists seem to ignore its existence and still say the estrous cycle is a lower mammal based process.

As humans (the species) evolved, the need for various primitive processes diminished. After all, we don't need to wait for that once a month moment, called estrous, to have sex. Humans have sex at will, assuming a willing partner. We engage in sex often in youth and with diminishing frequency as we age. This pattern is also hormone dependent, though altered by our human trait of making sex much to do about mental processes that are influenced by hormones but not at all entirely.

Understanding that the human female does, in fact, have a form of estrous cycle helps to know why women, more than men, may at times refuse sex, and at other times become very carnal - a euphemism for horny. Because of a highly developed cerebral cortex, the estrous cycle can be superseded by such things as flowers, candy and jewelry that can encourage sexual activity beyond the effects of hormones.

The next most obvious question - Do men have an estrous cycle? For that answer you will you will have to find the chapter titled, Do men have an estrous cycle?