but to perhaps make you feel less alone in your animal knowledge, it is only recently I found out that kangaroo babies are born when they are still an embryo, only spending a month inside her before being born tiny little jellybean sized, blind and without any hair, they crawl by themselves into their mother's pouch - using their two front paws to climb using her hair - which serves as an external womb, they latch onto one of her nipples in place of an umbilical cord, and the fetus grows until the joey is ready to be "born" 7 or 8 months later! I always though the pouch was just a way the kangaroo carried her baby after it was born, not that it literally grew into a full-size kangaroo inside it! that's why baby kangaroos often want to be carried in their mama's pouch - because it feels safe & familiar to them, like being back in the womb and it is also in the pouch where they are fed milk after birth.
ALSO a kangaroo can get pregnant while she still has a baby that isn't ready to be born in her pouch, but she can't grorw two babies at once, so after fertilisarion, her body pauses the pregnancy at the embryonic stage, and when the baby she is already carrying reaches full-term, her body knows to reactivate the pregnancy and the embryo that has been. on pause for potentially over 200 days begins to develop!
literally blew my mind!