Is Sea Otter Brain Infection Responsible for Elevated White Shark Attacks?

Toxoplasma gondii

Toxoplasma gondii - a parasitic protozoan that causes fatal brain infections in sea otters.

Research has revealed that when rodents infected with Toxoplasma gondii (a parasitic protozoan that causes fatal brain infections in sea otters) smell cat urine, they’re aroused rather than frightened… so instead of running away, they get eaten.  Could T. gondii be a contributing factor in the increase in sea otter deaths attributed to white shark attacks?

In more severe cases of toxoplasmosis, the inflammatory response to the parasite permanently damages the brain, which can cause seizures and loss of consciousness. Sea otters with either mild or severe brain damage may be more likely to get bitten by sharks because their fear of predators, or their ability to detect and elude them is compromised.


Related links:

Disturbing trend — sea otter deaths linked to white shark attacks are on the rise.

The Land-to-Sea Link: Disease and Contaminants

Behavioral changes induced by Toxoplasma infection of rodents are highly specific to aversion of cat odors

Predator Cat Odors Activate Sexual Arousal Pathways in Brains of Toxoplasma gondii Infected Rats

Toxoplasma’s Dark Side: The Link Between Parasite and Suicide


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About is dedicated to raising awareness about California's threatened sea otters and the role research plays in the species recovery and conservation. It's a collaboration of the Monterey Bay Aquarium, U.C. Santa Cruz, U.C. Davis, U.S. Geological Survey, U.S. Fish & Wildlife Service, California Department of Fish and Wildlife, among others. is also home of the world's first HD live stream of southern sea otters in the wild.