Dogs are viviparous because almost everyone has seen them give birth. Breed and mother affect litter size. Average dog litter size is five to six puppies.
Dogs
Even dog folks like kittens. Many urbanites have seen a dog or cat give birth. Most cat mothers have four kittens that are dependant for three weeks. A week of blindness. 7-10 days later, eyes open.
Cats
Rare twin foals are dangerous to mother and foal. A mare has 16 foals. Foals are world-ready. Most can gallop from birth. Nearly newborns can stand, walk, and trot. Horses and other herbivores do this.
Horses
Almost all deer species have one fawn at a time, and they're all spotted. Deer fawns are born walking, running, and standing. Unlike foals, fawns are generally hidden while their moms forage.
Deer
Rodents have mastered childbirth. A sector. No other mammals or vertebrates can reproduce like rats. Female mice and rats can have five to ten litters every year, each with six to eight pups.
Rodents
Domesticated cows have one calf at a time. Baby calves can stand, walk, and run soon after birth. In huge animals like cattle, growth and development take longer.
Cows
Elephant seals and fur seals give birth in huge colonies on the seashore, protecting their young from predators. Arctic seals live alone and bury their babies in ice dens. Polar bears are adept at finding dens.
Seals
Even though monkeys are smaller than apes, they only have one or two kids at a time. Because their offspring develop faster and they reach sexual maturity at an earlier age, they reproduce more often than apes.
Monkeys
Giraffes have a difficult birth. Birthing is risky due to their height. Baby giraffes fall 6 feet when born. They've solved the problem by making it part of birthing.