Did you know that we can learn about the biology of animals through their feces?

Yes, their poop!

Here’s the scoop on studying poop at the New England Aquarium: Currently, scientists in the Anderson Cabot Center for Ocean Life are partnering with New England Aquarium’s Marine Mammal Team to try to develop a new way to study the endocrinology of the northern fur seals living at the New Balance Foundation Marine Mammal Center … using feces!

katie at work in lab
Anderson Cabot Center researcher Katherine Graham works in the lab.
Endo-what?!

Endocrinology is the study of hormones. Hormones are tiny chemicals that circulate in the blood to signal all sorts of bodily processes, including growth, metabolism, reproduction, and many others. The hormones that we are studying in the fur seals are the same types of hormones found in our bodies (and in many other animals)!

fur seal on rock
A northern fur seal is perched on a rock in the Marine Mammal Center.
So how do hormones end up in feces?

After the hormones have relayed their message, they are broken down by the body and ultimately get excreted in the feces.

Why use feces—couldn’t you measure them in blood?

Our Marine Mammal and research teams wanted to partner on a project to find new ways to study the health of the animals under their care. Hormones can be measured in blood, but we wanted to try using feces because it can be collected without disrupting the seals’ day-to-day activities. As opposed to taking a blood sample, the Marine Mammal trainers can just pick up the scats left behind as they clean the pool area.

katie in lab
Katherine Graham pulls fecal samples from the freezer.
How do you know whose poop is whose?

The Marine Mammal Team came up with a creative way to tell the feces apart. Each seal is fed a unique diet item (like lentils, sesame seeds, and flax) inside their typical fish diet. Since these food items don’t get fully digested, they appear in the scat and we can match the sample to the seal that made it.

Every day, trainers collect fecal samples with a net from the bottom of the fur seal exhibit. We inspect the samples for any markers to know which seal it is from. We then put the fecal samples in labeled bags (name of animal and date) and store them in a freezer. Once a week, the samples are brought up to the research department. We are lucky because the New England Aquarium is one of the few aquariums in the world that has a lab on-site to study hormones!

preparing dried poop sample
A dried fecal sample has dietary markers sifted out. This one had sesame seeds in it!
vials of feces samples ready for testing
These fecal samples have been processed and are ready for testing.
How do you measure hormones?

In the lab, we perform several steps to extract the hormones from the feces and then measure the hormones using special tests called immunoassays. Currently, we are developing methods to measure hormones related to reproduction.

katie pipetting
Katherine Graham measures fecal hormones using an immunoassay.
assay plate
An immunoassay plate
Why study hormones?

By studying these hormones we can learn more about our seals at the Aquarium—for example which seals are going through puberty. Knowing more about the biology of the animals helps us provide them with the best possible care. 

Scientists in the Anderson Cabot Center for Ocean Life have performed similar studies for many years on other marine species—such as monitoring stress levels of endangered North Atlantic right whales in response to human impacts, such as noise and entanglement in fishing gear. These data are important to support conservation efforts for the species.

— Katherine Graham

Next time you are visiting the New Balance Foundation Marine Mammal Center see if you can spot any of the trainers collecting seal scat samples—for science! And keep an eye out for information about our research on fecal hormones.

signage in the MMC
Signage in the New Balance Foundation Marine Mammal Center

The Scoop on Poop: Secrets in Seal Scat!