* Size difference: River otters are significantly larger and heavier than red foxes. While a red fox might be able to take down a young or injured otter, a healthy adult otter would likely be too strong and agile for a fox to subdue.
* Dietary preferences: Red foxes are opportunistic omnivores, but their primary diet consists of small mammals, birds, insects, and fruit. River otters are primarily fish eaters, and their diet includes other aquatic creatures like crabs and crayfish. This difference in diet means they don't usually compete for food.
* Habitat overlap: While red foxes and river otters can share some habitat, they often occupy slightly different ecological niches. River otters are more strongly tied to water and aquatic environments, while foxes are more terrestrial.
While it's technically possible for a red fox to scavenge on a dead otter, it's not a typical predator-prey relationship.