Sea Otter
Even sea otter populations may hurt by domestic cats. The Toxoplasma gondii parasite the animals carry can leach into seawater when the cats defecate. The parasite is known to sicken and kill sea otters; recent research has indicated the parasite killing the otters is coming from domestic cat populations, though an earlier study found that the parasite sickening otters more likely comes from wild sources.
The parasite was still killing sea otters as of March 2022, according to a study published in Frontiers in Marine Science, which described four dead sea otters that all had an unusual inflammation of their body fat.
