Emeritus Professor Susan Suarez

The bowl deposits the semen into the vagina at the entrance to the cervix.

The bowl deposits the semen into the vagina at the entrance to the cervix.

In some other species, such as the pig, the penis goes all the way through the cervix and lets out the seminal plasma and the sperm directly into the uterus.

In some other species, such as the pig, the penis goes all the way through the cervix and lets out the seminal plasma and the sperm directly into the uterus.

And pigs also ejaculate about a half a litre.

And pigs also ejaculate about a half a litre.

Same thing with the mouse, the sperm really go directly into the uterus and don't have to pass through the cervix.

Same thing with the mouse, the sperm really go directly into the uterus and don't have to pass through the cervix.

So where you deliver the sperm can be really, really different.

So where you deliver the sperm can be really, really different.

But maybe I was wrong.

But maybe I was wrong.

Mice were made by Dr. Okabe in Osaka, Japan.

Mice were made by Dr. Okabe in Osaka, Japan.

Susan Suarez from Cornell University.

Susan Suarez from Cornell University.

In which the male mice produced sperm that had a green fluorescent head and a red fluorescent tail.

In which the male mice produced sperm that had a green fluorescent head and a red fluorescent tail.

And this meant scientists could track what the sperm was up to inside a female mouse.

And this meant scientists could track what the sperm was up to inside a female mouse.