What mammal mother has babies nearly one third her own size?

Answer: The correct answer is - Porcupine.

Porcupines are large sized, slow moving rodents (mammals belonging to the order rodentia), which have sharp spines present on their body for protection against predators. Their body weigh 1.2 to 35 kilograms depending upon the species.

Gestation period of female porcupines is 16 to 31 weeks, depending on species. They give give birth to 1-3 babies at one particular time.

Size of their babies is nearly one third of her own size.