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Scientists unlock secrets of endangered whale pregnancy via surprising source: poop

When a species is on the brink of extinction, every birth is cause for celebration. That’s the case for North Atlantic right whales, whose population has fallen to only about 336, according to the North Atlantic Right Whale Consortium.

After barely surviving centuries of whaling, the blubbery mammals today risk fatally colliding with boats or being entangled in rope and fishing gear as they migrate between waters off Florida and Canada each year.

“These are phenomenal animals. They have a lot of resilience,” said Liz Burgess, a research scientist at the Anderson Cabot Center for Ocean Life at the New England Aquarium in Boston. “They came back from the brink of extinction. So we still have a lot of hope that if we can make some changes out there, then they can keep thriving.”

The dire situation for right whales is driving her team to more aggressively and proactively look for signs of pregnancy from an unusual source: whale excrement.

“It's precious,” Burgess said, holding a vial of fecal extract in a lab just a few floors above the aquarium’s bustling penguin exhibit. “It contains a wealth of information.”

For the last two decades, scientists have been studying hormones trapped inside right whale poop to detect not only pregnancies, but male sexual maturity, metabolism, and stress.

This winter, Burgess and her colleagues began testing samples from one of the critically endangered whales, a female that researchers have named Koala, whose floating poop was scooped up in Canadian waters.

“It looks like a terracotta, right here, in the frozen state,” Burgess said, pulling a sample out of a freezer set to minus 112 degrees Fahrenheit. It’s one of more than 400 such samples kept at the aquarium, which makes it likely the world’s largest collection of right whale poop.

“On the water, usually, it's a brilliant orange, and that color comes from the food that the right whale eats. They eat copepods,” she said, referring to tiny, flea-like crustaceans.

After the poop is freeze-dried and crushed into a cinnamon-colored powder, scientists test a sample for the hormone progesterone. Burgess’s colleague Katie Graham said the levels can be hundreds of times higher for pregnant females.

“And for Koala's sample,” Graham said, “[I] got that excited feeling in my stomach like, ‘Oh my gosh, maybe she's going to be pregnant!’ And so as soon as I … saw the number pop up, I was like, ‘Wow, that's a lot of progesterone.’”

The results supported Graham’s intiution: 13-year-old Koala, one of only about 100 breeding-age females left in the population, is expecting her first calf.

Koala (Catalog #3940) is spotted during an aerial survey on June 6, 2018.
Peter Duley, NOAA/NEFSC
Koala (Catalog #3940) is spotted during an aerial survey on June 6, 2018.

Scientists say the prospect of Koala giving birth is especially encouraging because as recently as 2018, not a single right whale calf was detected. This winter, eleven have already been spotted, and many experts hope to see at least 20 more.

To Burgess, learning that a right whale is pregnant is a huge deal.

“This species is in a really critical state right now. There are more deaths than there are births,” she said. “So knowing that there's potentially another calf on the horizon to add to this population is absolutely crucial.”

But, she said, determining pregnancy is only the first part of the battle.

Now researchers will spend the next few months trying to locate Koala in the breeding grounds or northern feeding areas where, hopefully, a healthy calf will be by her side.

“It really does represent hope for the species,” Graham said.

Eve Zuckoff covers the environment and human impacts of climate change for CAI.