Cats are the sole host of toxoplasmosis. Photo: NOAA
Monk seals are a beloved part of Oahu’s ecosystem. For proof, look no further than the absolute shitstorm that erupted when a tourist threw a rock at one earlier this year. However, while that creature was able to emerge from the ordeal unscathed, another monk seal met its untimely death this year – and the cause of death has just been revealed.
Monk seal RH32, also known as Ka’ale, first rose to fame in October 2018, when he was found with a large, barbed circle hook stuck to his tongue. The then two-year-old seal was rescued by NOAA officials. After a NOAA veterinarian and team located on Ford Island removed the hook, the seal was released back to the wild. At the time, Ka’ale was hailed as a symbol of the danger that fishery interactions, including hookings and entanglements in nets, presented to Hawaiian monk seals. In just his first two years of life, Ka’ale had been hooked at least six times.
A dead seal that washed ashore off the coast of Nanakuli in May was later identified as Ka‘ale. “Our team is now performing a post-mortem examination to evaluate any factors that could help clarify what happened to this seal, who was well-loved by the local community.” wrote NOAA in a post. “A thorough examination with diagnostic assessments can take several weeks to complete.”
Now, the results are in, and it turns out that Ka’ale was killed by toxoplasmosis, an infectious disease that can cause serious health problems for wildlife and humans. It is caused by the parasite Toxoplasma gondii, which reproduces in the intestines of cats and then is spread through cat feces.
“Toxoplasmosis poses a significant threat to monk seals,” wrote NOAA. “It may cause the loss of a fetus and often leads to inflammation and dysfunction of internal organs, which can lead to debilitation and death. Infected monk seals may also display behavioral changes, such as floating listlessly (logging), which often happens before death. Logging is generally understood to be a sign of pain from the inflammation associated with an infection or injury.”
As of 2026, there have been 16 confirmed cases of seals dying due to toxoplasmosis in Hawaii. However, the actual number of toxoplasmosis-induced deaths is likely to be higher. Though that may not seem like an exceptionally high number, there are only around 380 seals in the main Hawaiian Islands, making toxoplasmosis a leading cause of monk seal deaths.
