Animal Reproduction

Menopause in Toothed Whales

October 13, 2021 0

The only other group of animals that experiences menopause to the extent that humans do is the toothed whale. Short-finned pilot whale and ecotype resident killer whale females can live to the age of ninety; […]

Animal Reproduction

Cryptic Female Choice

August 25, 2021 0

“Cryptic female choice” is essentially a female’s way of exercising some post-coital power over whose sperm will fertilize her eggs. There are many reasons why a female would want to retain some kind of control […]

Animal Reproduction

Male Rats Run Out Of Sperm But Still Engage In Sex

August 18, 2021 0

Rats (superfamily Muroidea) have a well-studied mating system that often involves males becoming sexually satiated. This means that they literally get tapped out of sperm and it takes approximately fifteen days for their fertility to […]

Animal Reproduction

Obligate Diapause – Suspending Pregnancies in Carnivores

August 11, 2021 0

As opposed to the rodents who experience facultative diapause, carnivore moms experience obligate diapause. Obligately diapausing mothers experience a period of embryonic inactivity each time a pregnancy occurs. Regardless of environmental conditions, there is a […]

Animal Reproduction

The Grandmother Hypothesis for Menopause

July 28, 2021 0

We’ve already covered one hypothesis for why menopause exists, but there is another main hypothesis for the advent of reproductive cessation, and this one is an adaptive one. Picture it: as ancestral humans were expanding […]

Animal Reproduction

Female Fire Salamanders Can Store Sperm For Months

July 14, 2021 0

In many anuran (frog and toad) species, females have a sperm-storage organ (a spermatheca) that enables them to keep sperm for long periods of time. This too can allow for the possibility of female choice […]

Animal Reproduction

Female Tree Crickets Prefer The Bad Boys

June 16, 2021 0

The human female is a complicated creature. The selection of an appropriate mate is often an extremely difficult process that can lead to sadness and heartache when we get it wrong. It seems so simple […]