It's just the female.

Those females, they're not trying to.

The gourd is a feminine aspect the stick is a male.

You can engineer a prairie vole to become monogamous when it's naturally polygamous.

DG This is a female of this kind of worm.

And, interestingly, this has been observed in female macaques, but only when mounting another female.

Females after their first calf is already weaned a lower load.

Now, it turns out we only kill the female mosquitoes.

And the second is a phenomenon that males are very, very good at finding females.

So when you develop a cancerous cell in your breast, aromatase converts androgens into estrogens, and that estrogen turns on or promotes the growth of that cancer so that it turns into a tumor and spreads.

Specifically, it's male fireflies who are all flashing in perfect time together, in perfect synchrony, to reinforce a message to the females.

So here's a typical situation, male meets female, lots of offspring.

As Darwin did not believe that pure aesthetics would guide female peacocks and lions in their choice of mating partners, he had to find a rational reason for females preference for males with hindering characteristics. The very fact, he reasoned, that these features make life harder signals to prospective partners that individuals who can do reasonably well with them have an especially good genetic set up and are thus likely to produce strong offspring.

There are over eight words for what they call animal favoritism selective proceptivity, mate choice, female choice, sexual choice.

Because it turns out that the number one cancer in women, breast cancer, is regulated by estrogen and by this enzyme aromatase.

The death rate in these dolphins, for the first calf born of every female dolphin, is 60 to 80 percent.

Down below here, we see calls made by both males and females that also carry over very long ranges.

And these two males are fighting, they do it by bouncing their butts together, which is an interesting concept. Now, here's a male on the left and a female on the right, and the male has managed to split his coloration so the female only always sees the kinder gentler squid in him.

Gracia is a cute female toucan, exuding the breath of tropical rain forest.

It's only the female mosquito that will actually bite you.

If there's a male mosquito that you release, and if there's a female around, that male will find the female.

But what atrazine does is it turns on an enzyme, the machinery if you will, aromatase, that converts testosterone into estrogen.

And this is not just philosophical, it's already known, that chemicals like diethylstilbestrol and estrogen, PCBs, DDT cross the placenta and effectively determine the likelihood of developing breast cancer and obesity and diabetes already when the baby's in the womb.

We've separated the males from the females.

There's only 8,000 basking shark females in the world?

He's coming up to one of my graduate students and flipper patting, which he would do to a female penguin.

So if we can tell the gender of the shark before we sample it, we can tell the geneticist this was taken from a male or a female.

He stresses the importance of checking for bats before carrying out maintenance within properties as it is possible unwitting destruction of a single maternity roost could kill up to 400 females and young, possibly wiping out an entire local population.

In addition, the female Greenland shark is alleged to be sexually matured at about 4 meters in length. That is, it can only reach adulthood at least until the age of 156.

She always knows where he is, and she doesn't have to be monogamous, because some of these females come up with multiple males attached.

I would even say that with Viagra, estrogen replacement, hip replacements and the incredibly interesting women women have never been as interesting as they are now.

And she says, What? Only the females have eggs?

So we're dosing our babies, our newborns, our infants, with a synthetic estrogen.

And what's interesting about BPA is that it's such a potent estrogen that it was actually once considered for use as a synthetic estrogen in hormone placement therapy.

Women's ability to find the right word rapidly, basic articulation goes up in the middle of the menstrual cycle, when estrogen levels peak.

And as a result, these exposed males lose their testosterone, they're chemically castrated, and they're subsequently feminized because now they're making the female hormone.

What you're seeing here is very recently shot images in a forest nearby here, of a female king cobra making her nest.

It's a material hardener and synthetic estrogen that's found in the lining of canned foods and some plastics.

PJC So speaking of estrogen, one of the other compounds that Tyrone talks about in the film is something called bisphenol A, BPA, which has been in the news recently.

So the males will go out, they'll look for females, they'll mate. If they mate successfully, then no offspring.

In fact, more genetic profiling told us that this tumor in Jonas actually probably first arose from the cells of a female Tasmanian devil and Jonas was clearly a male.

In fact, of those 20,000, 8,000 were thought to be females.

We gave samples to Mary Schweitzer, and she was actually able to determine that B rex was a female based on medullary tissue found on the inside of the bone.

And I have concocted a questionnaire to see to what degree you express dopamine, serotonin, estrogen and testosterone.

So, now we believe that the different shape of the lure is how the male recognizes the female in the anglerfish world, because many of these males are what are known as dwarf males.