However, nutria can have up to 13 young per litter and may have 3 litters per year. In Maryland, they average four young per litter. Young are born fully furred and active, weighing 8 oz. at birth. They can swim and eat vegetation shortly thereafter, with weaning occurring 7 to 8 weeks after birth. Within 5 days after birth, nutria can survive away from the mother.
Nutria feed almost entirely on vegetation.
They are opportunistic feeders with an extremely varied diet. Nutria also eat crops, lawn grasses, and ornamentals adjacent to aquatic habitats, and limited crop depredations have been documented. They have a high reproductive capability. They have no natural predators. They cause extensive damage to marshes.