What do water rats eat? - briefly
Water rats feed mainly on aquatic insects, crustaceans, small fish, and plant matter such as algae and seeds. Seasonal changes cause a higher proportion of vegetation in their diet during colder months.
What do water rats eat? - in detail
Water rats, members of the genus Hydromys and Paraleptomys, are primarily omnivorous mammals that forage in aquatic and riparian habitats. Their nutritional intake reflects the availability of both animal and plant resources in fresh‑water ecosystems.
The animal component dominates their diet. Typical prey includes:
- Aquatic insects (larvae of mosquitoes, beetles, and caddisflies) captured by diving or surface swimming.
- Small crustaceans such as freshwater shrimp and amphipods, often taken from submerged vegetation.
- Fish fry and juvenile amphibians, especially tadpoles, which are seized during night foraging.
- Mollusks, including small freshwater snails and bivalves, cracked with strong incisors.
Plant matter supplements the protein‑rich diet. Commonly consumed vegetation comprises:
- Tender shoots and leaves of aquatic macrophytes (e.g., watermilfoil, pondweed).
- Seeds and fruits that fall into the water, such as those of water lilies or riparian shrubs.
- Algal mats adhering to submerged surfaces, occasionally ingested incidentally.
Seasonal fluctuations influence the proportion of each food category. In warmer months, insect larvae and amphibian larvae are abundant, leading to a higher intake of animal protein. During cooler periods, when prey density declines, water rats increase consumption of plant material and detritus to meet energy requirements.
Digestive adaptations support this varied diet. Sharp, continuously growing incisors enable the animal to gnaw through hard shells, while a relatively long gastrointestinal tract facilitates fermentation of fibrous plant matter. Studies of stomach contents across different regions confirm that the species can adjust its foraging strategy to exploit the most accessible resources, ensuring survival in diverse freshwater environments.