You might not know it, but this month is testicular cancer awareness month, which seeks to try and raise awareness about the disease.

Testicular cancer is the most common form of cancer in men from ages 15 to 45, with the condition fatal to one in 40 people who get it. However, it’s easy to check yourself and get treatment, and it is 98 percent curable if detected early.

To further highlight the month, we thought we’d bring you some interesting facts about testicles. So sit back and relax as we tell you a thing or two about balls.

That’s a lot of sperm

Sperm, more scientifically known as spermatozoa, are made in vessels within the testicles called seminiferous tubules. The average fertile man produces 40 to 60 million sperm cells per milliliter of semen, and testicles create about 200 million sperm every day.

Biggest balls

The biggest testicles in the animal kingdom belong to the tuberous bushcricket, also called Platycleis affinis, at least in relation to its body mass. They account for about 14 percent of the insect’s weight; if the same were true of a man, they would weigh about the same as six bags of sugar.

In terms of pure size, though, it’s right whales that come out on top. Each of their testicles weighs about 500 kilograms (1,100 pounds), containing about 1 percent of the whale’s weight and able to produce about 4.5 liters (1 gallon) of semen. Impressive.

Some like it cold

Testicles like to be cold, which is why your body tells them to hang down when you are warm. When they’re too cold, they often shrivel up to try and retain some heat.

For about 65 percent of men, the right testicle hangs a bit higher and is also bigger, although Greek statues normally have a larger left one – possibly for reasons relating to fertility and cultural beliefs.

Scrotum humanum

In 1763, physician Richard Brookes described a fossil found in the UK that may well have been the first dinosaur. Although correctly identified as part of a femur, he gave it a name that referenced its similar appearance to a giant human’s testicles: Scrotum humanum.

Later, this fossil was attributed to the dinosaur Megalosaurus, the first dinosaur to be scientifically named in 1824. But the creature was allowed to keep its new name by the International Commission for Zoological Nomenclature, despite being originally referred to simply as “balls”.

More than two

Not all men have two testicles. There is an extremely rare condition called polyorchidism where a man can grow one to three more testicles than normal.

Only about 200 cases have ever been reported, with the extra testicles found via ultrasound. Sometimes the extra testicles may be removed, as it’s thought they can increase the risk of testicular cancer.