Living Fossils and Vaccines (B1-B2/v1152)


Horseshoe crabs have a unique type of blood that makes sure any medical product we put in our body is free of bacteria. But scientists say the horseshoe population is vulnerable and are very concerned about the next decade.


TV Journalist:  This morning we continue our “Eye on Innovation” series on the increasing role science and technology play in our lives.  We’re learning how horseshoe crabs could play a key role in the development of a vaccine for the Corona Virus.  But scientists are increasingly concerned about their survival.  Tom Hanson shows us the fight to save these extraordinary animals.

Tom Hanson, TV Journalist:  Each year from Maine to Mexico guided by the moon countless horseshoe crabs complete an annual journey older than the dinosaurs.  One that is crucial in developing a Covid-19 vaccine.

John Tanacredi, Molloy College Cercom Director:  These animals have been on the planet for over 445 million years give or take a week or two in there.

Journalist:  This is a living fossil.

Tanacredi:  Yes it is.  That’s the male…

Journalist:  Scientist, John Tanacredi has dedicated his life to studying these so called “living fossils”.

Tanacredi:  Pretty active, very healthy, that’s good.

Journalist:  He runs the Center for Environmental Research and Coastal Oceans Monitoring Program at Malloy College, the largest horseshoe crab breeding lab in the Western Hemisphere.  His team tracks 115 beaches around Long Island.  They say the Horseshoe crab population is in dire straits.  How much time are we looking at here before we lose horseshoe crabs?

Tanacredi:  I’d say the next 10 years…the next decade is of critical concern.

Journalist:  Critical concern not just for the eco-system, but also for modern medicine.  Pharmaceutical companies have relied on these pre-historic creatures for decades to the dismay of conservationists.  It’s all because of how their blue blood keeps them safe.  A unique feature that helps scientists quickly detect deadly bacterial  toxins.

John Dukcheck:  We recognize, and most people recognize, that this is a valuable resource.

Journalist:  John Dukcheck is an executive director at Charles River Laboratories.

Dukcheck:  It really represents, you know, lots of evolution and the horseshoe crab blood is exquisitely sensitive to these endotoxin pyrogens.

Journalist:  You’ve likely never heard of these dangerous toxins, but it all started with a professor at Johns Hopkins University named Dr. Frederick Bang.  In 1956 he observed a horseshoe crab become naturally infected with vibrio bacteria and then witnessed the crab’s blood actually clotting around that bacteria.

Dukcheck:  When they’re in the shallow water they’re awash in these bacteria, so if they get injured the hemocytes recognizes these bacteria, they recognize it as an opportunity to get an infection so they clot.

Journalist:  That reaction became the basis for this test which checks for bacterial contamination in any medical product that goes into the body before the manufacturer ships them out including IV drugs, heart valves and, yes, vaccines.

Dukcheck:  We have a 450-million-year-old creature that for the last 45 years has improved the safety of medicines for humans and animals.

Journalist:  In the US limits have been put on how many horseshoe crabs can be harvested each year.  And while the humble horseshoe crab’s cells can be removed with no apparent harm to the creatures, studies show biomedical harvesting, overfishing for bait collection and coastal development are causing a drop in the population raising major questions about their survival.

Tanacredi:  There is a public concern, a real concern about these animals that if we lose their habitat or we lose them coming to shore, once you lose them, they’re gone.  Extinction is forever.

Journalist:  But with a global push for a Covid-19 vaccine underway, horseshoe crabs are once again in the spotlight which Tanacredi hopes will help conservation efforts.

If enough people can hear about it and talk to it that helps in getting the attention.  This has been going on long before a pandemic as issues and concerns for these animals and our health so I’m optimistic.  You have to be.

Journalist:  For CBS This Morning, Tom Hanson, West Sayville, New York.



1. These animals have been on the planet for over 445 million years ________ a week or two in there.
2. His team ________ 115 beaches around Long Island.
3. Pharmaceutical companies have relied on these pre-historic creatures for decades to the ________ of conservationists.
4. It was Dr. Frederick Bang, a professor at Johns Hopkins University, who first witnessed the horseshoe crab’s blood actually ________ around infecting bacteria.
5. Horseshoe crab cells became the basis for checking for bacterial contamination in any medical product that goes into the body before the manufacturer ________ them out including drugs, heart valves and vaccines.


  1. Have you ever seen a horseshoe crab in the wild or know what one looks like?
  2. What are some examples of human activities that are placing a major burden on wildlife habitat and biodiversity?
  3. Many scientists agree that massive loss of biodiversity represents a major threat to the planet.  How can we balance the need to produce medications and goods for the human population with the need to restore biodiversity on Earth?