快猫短视频

Why is the scrotum so wrinkly?

鈥� The scrotum plays a valuable role in thermoregulation of the testicles, as sperm production is reduced at core body temperatures and above. Those of us with this piece of anatomy will have noticed that on a very cold day, or when emerging from a cold shower, the scrotum (and the rest) will be much smaller. The converse happens on a warm day or on emerging from a hot bath. The scrotum is quite smooth when relaxed and only wrinkles as it is pulled tight to the body.

This is because muscles within the scrotal wall contract to bring the testicles nearer the abdomen in cold conditions, and relax to keep them cool when it is hot. There is also a complex system of vasculature in the spermatic cord (), where warm blood leaving the abdomen is cooled by a heat exchanger system before entering the testicles.

When farmers first started to rear Merino sheep in Australia, they found that the rams were sterile until sheared, so their testicles are shorn on a regular basis today. This breed of sheep originated in southern Portugal, where summer temperatures are not as high. Consequently the rams have unsuitably woolly scrotums for southern Australian conditions.

Bob Butler (retired vet), Llangoed, Anglesey, UK

We pay 拢25 for every answer published in 快猫短视频. To answer this question 鈥� or ask a new one 鈥� visit newscientist.com/lastword. Terms and conditions apply.

This article appeared in print under the headline 鈥淣utty question鈥�