- Myocastor coypus, known as the Coypu or Nutria, is a large, semi-aquatic rodent native to South America that has been introduced worldwide. This adaptable species has become significant both as an invasive species and as a fur-bearing animal of economic importance.
- Physically, Coypus are substantial rodents, weighing 4-9 kg and measuring 40-60 cm in body length, with a tail adding another 30-45 cm. Their body is robust and well-adapted for aquatic life, with partially webbed hind feet, valvular nostrils, and lips that close behind their large orange incisors to allow underwater feeding. Their fur is double-layered, with coarse guard hairs over a dense, waterproof underfur.
- Their most distinctive features include prominent orange-colored incisors, long and stout whiskers, and small eyes and ears positioned high on their head for surface vision while swimming. Their tail is round in cross-section, unlike the laterally flattened tail of beavers, and is sparsely haired, serving primarily for balance and steering while swimming.
- The species shows numerous adaptations for their semi-aquatic lifestyle. Their mammary glands are positioned high on their flanks, allowing young to nurse while the mother remains largely submerged. Their metabolic rate and thermoregulation are efficient, enabling them to cope with cold water.
- Their habitat preferences include freshwater marshes, slow-moving rivers, lakes, and estuarine areas. They require abundant aquatic vegetation and accessible banks for burrowing. They show remarkable adaptability to various wetland environments, from tropical to temperate regions.
- Behaviorally, Coypus are primarily crepuscular and nocturnal, though they may be active during daylight hours where undisturbed. They are excellent swimmers and can remain submerged for several minutes. They construct platforms of vegetation for feeding and resting, and create burrows in banks for shelter and breeding.
- Their diet consists mainly of aquatic vegetation, including stems, leaves, and roots. They consume approximately 25% of their body weight daily and can significantly impact wetland vegetation through their feeding habits. They also eat some agricultural crops when available, leading to conflicts with farmers.
- Social organization involves small family groups typically consisting of a breeding female, her most recent offspring, and occasionally adult males. They communicate through various vocalizations and scent marking. Groups often share feeding areas and burrow systems.
- Reproduction is highly efficient, with females capable of breeding year-round and producing multiple litters annually. Gestation lasts about 130 days, with litters averaging 5-6 highly precocial young. Young can swim and eat vegetation within hours of birth, contributing to the species’ invasive success.
- Conservation status is complex, as they are considered both a threatened species in their native range and an invasive pest in many introduced areas. Management often focuses on population control in introduced regions while preserving native populations in South America.
- The species plays significant ecological roles, both positive and negative. In their native range, they help maintain wetland diversity through grazing and nutrient cycling. In introduced areas, they can severely impact native vegetation and wetland structure.
- Research has focused on their impacts as an invasive species, their potential for sustainable fur harvesting, and their role in wetland ecosystems. Their adaptability and reproductive capacity make them important subjects for studying biological invasions.
- Management efforts vary dramatically by region, from eradication programs in areas where they are invasive to conservation measures in their native range. Control methods include trapping, habitat modification, and exclusion techniques.
- Current conservation strategies in their native range emphasize habitat protection and sustainable harvesting practices. In introduced areas, management focuses on preventing spread and reducing impacts on native ecosystems.
- The species’ ability to modify wetland habitats makes them ecosystem engineers, capable of significantly altering local hydrology and vegetation structure. Their presence can indicate both healthy wetland systems in their native range and ecological disruption in introduced areas.
