1. Lionesses give birth in secret, away from the pride, to protect their cubs. After birth, they'll keep their babies hidden for up to six weeks.
2. Elephants remain pregnant longer than any other mammal, with an average gestation period of 95 weeks. That's almost 2 YEARS. Can you imagine?
3. When a giraffe gives birth, her baby falls to the ground (makes sense, seeing how tall giraffes are!), but the baby isn't hurt. What's more impressive: The baby is able to stand on his own usually within 20 minutes.
4. If, after an elephant gives birth, she finds her baby to be unresponsive, she'll kick it to induce breathing.
5. It's very difficult for female pandas to become pregnant — they only ovulate for a couple days in an entire year. What's more, according to NatGeo: Sometimes pandas "resorb, or absorb a fetus — a biological process that's still a mystery to scientists."
6. This is an X-ray of a pregnant dog. Litter size varies depending on the breed of dog, but labrador retrievers generally produce a litter of seven to eight puppies.
7. Opossums hardly have to be pregnant at all: The gestation period is a mere 14 days.
8. Although rarely observed by humans, some monkeys have been known to step in as midwife to assist in the birth of another monkey's baby.
9. Some otters experience "delayed implementation," meaning they are able to delay the development of their pregnancies in order to allow for a birth in an optimal month.
10. Here's another cool fact about otter moms: If they need to dive down into the water, they'll wrap their pup in seaweed or kelp to keep it from drifting away.
11. Lady emperor penguins leave incubating duties largely to their partners. He keeps the egg warm, while she leaves to feed, usually for a few weeks! And what does dear old Dad do that whole time? He FASTS. Damn.
12. So...male koalas have double-headed (or bifurcated) penises and the females have two vaginas. Also, the female has a third birthing vagina that opens after pregnancy occurs.