Endocrine Disruption

Possibly a good selection. Problems with endocrine glands and hormones have been in the news for the last few years. Many pesticides mimic estrogen hormones (called endocrine disruptors) and may be causing the decline in sperm production of male animals, including man, around the world. There is considerable evidence to indicate that sperm production is decreasing in large cats and the sperm that are being produced are not normal. Abnormal sperm may not have flagella, or they may have two heads or two flagella. Regardless, it difficult for them to swim through the female reproductive tract.

In studies of cheetah sperm, 71% were abnormal (as compared to 29% for most cats) and 46% were immobile (as compared to 23% for most cats).

• How do the percentages for abnormal and immobile cheetah sperm compare to those for human sperm?

While these numbers for cheetahs are the highest for felids, this does not mean that male cheetahs are sterile. On the contrary, they are not. In other studies,there were no differences in ejaculate volume or hormone profiles. While endocrine disruptors may be the cause of reproductive problems in some animals, this does not appear to be the reason for the decline in cheetahs at this time.