A male reproductive system is one of the most complex systems of living organisms, with multiple organs that are used to create sperm and eggs.
It is one reason we can’t reproduce as many times as we would like, according to researchers.
But how many times are there in a lifetime?
According to a study published in the journal Reproductive Medicine, a total of 14 different species of animals have a female reproductive tract.
In that study, researchers from the University of Toronto and the University at Buffalo were interested in finding out how many of the species can reproduce as long as they have a male reproductive organ.
So they asked more than a dozen animals to identify a female and a male.
In total, they asked animals ranging from wild boars and monkeys to fish, and found that most species of fish, including the mussel and oyster, can reproduce in one lifetime.
But fish can’t just reproduce in a single lifetime.
Researchers then tried to figure out how often the fish can reproduce.
Some of the animals had more than one male reproductive organs.
In other words, the fish would have to have a reproductive tract that was more than twice as long, to make sure it could reproduce as often as possible.
Researchers found that females had a reproductive organ that was roughly twice as large as males.
That’s a bit surprising because the larger the male reproductive tracts are, the longer they live.
In some cases, the female reproductive organ can last for 20 years or more, and the male can last up to 20 years.
“The male reproductive tissues are very complex, and so there’s a lot of potential that the male is going to reproduce for many, many, possibly many lifetimes,” said University of Buffalo senior scientist Jennifer Ouellette.
The researchers then took a closer look at the reproductive tract of the mussels.
They found that the musse was able to produce a female organ in about four days, whereas the male would take roughly seven to eight days to produce one.
“These mussels that we’ve seen have this reproductive tract over and over again, so it’s really quite remarkable,” said Ouelette.
Scientists have known for some time that the fish, like the musky sea bass, are able to reproduce in multiple lifetimes.
“It’s not uncommon for females to be able to live for years, and male fish can be around for decades,” said lead author Jonathan Zalman, a professor of biology at the University, “so this is a remarkable feat.”
The mussels have a special arrangement of organs that allow them to produce sperm and embryos in just a few days.
But they are far from the only animals able to do this.
Fish, including fish in the Atlantic and Pacific oceans, can live for hundreds of years.
Scientists also know that fish can live longer than 10 years in some cases.
The Atlantic salmon, for example, can be found in Canada for up to 10 years.
Ouelettes and Zalmans group also found that some animals, such as dolphins, have a unique arrangement of reproductive organs, and can live up to 80 years.
That includes the Atlantic right whale.
Oozes have the longest life spans in the animal kingdom, but they live longer in captivity, too.
“There are many species that have reproductive systems that are a lot longer than we normally think,” said Zalmen.
Oubre, who is also an author on the study, said the findings show that the reproductive system of the fish is not as simple as it may seem.
It might take many years to make a single fertilized egg and sperm.
“This is not something that is something that we know, and it’s certainly something that people are trying to figure things out,” she said.