Sperm come in tons of sizes, and it all has to do with how they have to find the egg.
From an evolutionary and biological perspective, animals are driven to have sex in order to procreate. But there is a lot more to sexual relations between animals. Animal sex is at least as strange and varied as human sex. A male might copulate with many females. And female animals of many species can be choosy, too. Homosexuality is common. Monogamy is rare. And the animal kingdom is full of swingers. In short, with animals, sex can be wild.
A productive grain harvest has resulted in a 'plague' of mice rampaging through Australia, and locals are sick of cleaning up their poo.
Enormous and powerful coconut crabs are known for their extreme size. They also have an unexpectedly diverse "vocabulary."
Little is known about the mating behaviors of arctic-loving narwhals, also called the unicorns of the sea.
The cringe-worthy sexual behaviors of bed bugs involve traumatic insemination, no courtship activities and, sometimes, incest.
Hummingbird mating involves using specialized courtship rituals, tail feathers that sing, and weaponized beaks.
For Valentine’s Day, Live Science gathers together some of the more extravagant and outlandish courtship rituals in the animal kingdom.
Chicken mating involves tidbitting, wing-flapping, a male waltz and the possibility of the female ejecting the male's sperm.
A monkey was recently seen performing sexual actions on the backs of female sika deer on Japan's Yakushima island.
Though nine-banded armadillos are solitary creatures, they do occasionally get together for some genital sniffing, tail wagging and clucking in order to have sex.