The crowd historian Elias Canetti claims in Crowds and Power that invisible crowds have always existed.
The most numerous, according to him, are those microscopic entities like bacteria and sperm.
Crowds of them that can't be counted, there are so many.
Think numbers stretching into infinity...
There are some average numbers, though, based on some serious scientific observation.
Hate to disappoint you, guys, but human males don't even close to the top ten in the average number of sperm per ejaculation in mammals.
According to The Book of Lists 2, here are the top ten:
Swine: 45,000,000,000
Jackass: 14,000,000,000
Horse: 8,000,000,000
Dairy Cattle: 7,000,000,000
Zebu (humped ox): 5,098,200,000
Beef Cattle: 4,000,000,000
Eurasian Buffalo: 3,978,000,000
Sheep: 3,000,000,000
Goat: 1,755,000,000
Dog: 1,500,000,000
The above numbers are in the billions! What I find interesting that humans often call each other swine and jackass to insult each other.
(Except those in certain parts of the gay community who are proud of being and behaving as various types of sex “pigs.”)
Perhaps these numbers would make you think twice, if quantity is your guide to value judgments, about using those terms as insults. In fact, I'm surprised pigs and asses haven't taken over the world, based on their sperm counts.
(By the way, the median sperm count for human males is about 255,000,000 per ejaculation, according to Wikipedia's article on semen analysis. Again, sorry, guys.)
And guys, try to think quality, not quantity.