APR 01, 2021 4:49 PM PDT

Scientists Solve Sea Lion Cancer Mystery

WRITTEN BY: Tiffany Dazet

For more than thirty years, scientists have tried to solve the mystery of the high prevalence of cancer among wild California sea lions. According to a study from The Marine Mammal Center (TMMC) in Sausalito, California, necropsies of adult sea lions that had stranded between central and northern California coast revealed that one in four had cancer. TMMC reports that “wild California sea lions have among the highest prevalence of a single type of cancer in any mammal, including humans.” More than 90% of the animals had urogenital carcinoma—cancer that originates in the genitals and rapidly spreads to lymph nodes and major organs.

According to TMMC, scientists hypothesized that a virus caused this cancer. New research confirms their suspicions, and the work done with California sea lions may be a valuable model for human cancer studies. The research results were published earlier this year in Animals.

According to the study, a sexually transmitted herpes virus is the main factor leading to sea lion urogenital carcinoma development. Additionally, the research suggests a trigger that causes the cancer to develop in some infected sea lions, but not others. Another recent study points to coastal pollutants like PCBs and DDT as the trigger. TMMC reports that in Southern California, there is a large DDT dumpsite near a large sea lion rookery, where pups are born each year.

Dr. Alissa Deming is this study’s lead author, and she is now the Director of Clinical Medicine at the Pacific Marine Mammal Center in Laguna Beach, California. In the press release from TMMC, she stated, “The confirmation that this is a virally induced cancer combined with the knowledge that contaminants play a significant role in the cancer’s development means that we can use these sea lions as a naturally occurring disease model to better understand how cancer develops and spreads in all species, including humans.”

As a coastal species, California sea lions are inherently tied to the health of coastal land and waters. TMMC reports that they’re exposed to dietary contaminants, infectious disease, and other environmental stressors throughout their natural range. According to TMMC, these sea lions are representative of how cancer develops in “the real world” rather than in traditional laboratory models, making them a valuable parallel to human studies. The research team is hopeful that their work can guide future research for cancer in humans.  

Sources: The Marine Mammal Center, Animals

About the Author
  • Tiffany grew up in Southern California, where she attended San Diego State University. She graduated with a degree in Biology with a marine emphasis, thanks to her love of the ocean and wildlife. With 13 years of science writing under her belt, she now works as a freelance writer in the Pacific Northwest.
You May Also Like
JAN 10, 2021
Plants & Animals
A Cuter Look at Saber Tooth Tigers
JAN 10, 2021
A Cuter Look at Saber Tooth Tigers
Recent work has suggested that saber tooth tigers aren't the terrifying predators they seem to have been; they may have ...
JAN 13, 2021
Plants & Animals
Dwarf Giraffes Observed for the First Time Ever
JAN 13, 2021
Dwarf Giraffes Observed for the First Time Ever
The name “dwarf giraffe” certainly seems like an oxymoron, which is why scientists were shocked to observe t ...
MAR 26, 2021
Plants & Animals
A Massive 17-Year Cicada Swarm will Emerge Soon
MAR 26, 2021
A Massive 17-Year Cicada Swarm will Emerge Soon
The east coast is preparing for one of nature’s greatest spectacles. A gigantic swarm of periodical cicadas is due ...
MAR 28, 2021
Plants & Animals
The Protein That Carnivorous Plants Use To Hunt
MAR 28, 2021
The Protein That Carnivorous Plants Use To Hunt
The Venus flytrap is famous for its ability to snap its leaves shut when they're triggered by the touch of an insect. Re ...
APR 09, 2021
Plants & Animals
Celebrating National Pet Day
APR 09, 2021
Celebrating National Pet Day
Sunday, April 11, is National Pet Day! From pandemic companions to viral videos, pets are a huge part of our lives. Even ...
APR 15, 2021
Chemistry & Physics
What can snakes teach us about durability?
APR 15, 2021
What can snakes teach us about durability?
A team of biologists, chemists, and engineers are studying snake locomotion in order to help them better design durable ...
Loading Comments...