It's important to note that different species of river otters have varying population sizes. Here's an approximate breakdown of river otter populations by some of the main species:
1. North American River Otter (Lontra canadensis):
- Estimated population: Several hundred thousand
- Widely distributed in Canada and the United States
- Can be found in freshwater habitats, including rivers, lakes, and wetlands
2. Eurasian River Otter (Lutra lutra):
- Estimated population: Tens to hundreds of thousands
- Found in Europe, parts of Asia, and North Africa
- Inhabits freshwater bodies such as rivers, streams, and lakes
3. Giant River Otter (Pteronura brasiliensis):
- Estimated population: Approximately 2,000-5,000 individuals
- Native to South America, mainly found in the Amazon and Orinoco River basins
- Considered a critically endangered species
4. Southern River Otter (Lontra provocax):
- Estimated population: Limited data, but potentially in the thousands
- Restricted to southern Chile and Argentina
- Inhabits freshwater habitats and coastal environments
5. African Clawless Otter (Aonyx capensis):
- Estimated population: Not precisely known, but potentially over 100,000
- Found in sub-Saharan Africa
- Prefers freshwater habitats, such as rivers, streams, and wetlands
6. Smooth-Coated Otter (Lutrogale perspicillata):
- Estimated population: Uncertain, possibly in the tens of thousands
- Distributed in Southeast Asia, including Indonesia, Malaysia, and Thailand
- Inhabits rivers and mangrove swamps
Please keep in mind that these population estimates are approximate and can change based on ongoing conservation efforts, environmental factors, and research. River otter populations can fluctuate due to habitat loss, pollution, hunting, and other human-related impacts.