Opossums:
* Premature: Opossums are born extremely underdeveloped, resembling tiny, blind, hairless pink worms. They are essentially helpless and require constant care from their mother.
* Large litters: Opossums can have litters of 10-20 joeys, which is significantly more than cats.
* Pouch: Opossums have a pouch where the joeys immediately crawl after birth and attach to a nipple to receive milk and grow. They stay in the pouch for several months.
* Blind and deaf: Opossum joeys are born blind and deaf, relying on their mother for everything.
* Short gestation: Opossums have a short gestation period, around 13 days.
Kittens:
* Developed: Kittens are born relatively developed compared to opossums. They have fur, open eyes, and can hear.
* Smaller litters: Cats typically have litters of 3-8 kittens.
* No pouch: Kittens are born with no pouch and are cared for in a nest.
* Can see and hear: Kittens are born with their eyes open and can hear, though their vision is blurry.
* Longer gestation: Cats have a longer gestation period, around 63 days.
Key differences:
* Development: Opossum joeys are extremely underdeveloped at birth, while kittens are more developed.
* Pouch: Opossums have a pouch, while cats do not.
* Litter size: Opossums have larger litters than cats.
* Gestation period: Opossums have a much shorter gestation period than cats.
Ultimately, the differences in birth are a result of the different evolutionary adaptations of these two species. Opossums have evolved to have a rapid reproductive cycle and a pouch to protect their vulnerable young, while cats have evolved to have a longer gestation period and more developed offspring at birth.