Whale Poop, Right Whales, and What Fossil Baleen Can't Tell Us

Every so often a paleontology headline reminds us how much we cannot read from bones alone. A new study of living southern right whales, built partly on samples one dedicated beachcomber kept in his freezer for years, is exactly that kind of reminder. It also lands close to home for South Carolina, where the coastal plain preserves some of the earliest baleen whales on Earth — and where a close cousin of the study's whales still swims past our beaches each winter.

The find behind the breakthrough

According to reporting from Phys.org and the University of Auckland, South Australian whale-watch operator Rod Keogh spent years collecting southern right whale scat that washed ashore at Fowlers Bay, convinced it had scientific value even when researchers were slow to bite. His samples eventually joined material from two sites in South Africa and from New Zealand's sub-Antarctic Auckland Islands (Maungahuka) in a study led by Macquarie University and the University of Auckland, published in Molecular Ecology.

The southern right whale (Eubalaena australis, called tohorā in Aotearoa New Zealand) is a conservation success story with a warning label attached. Whaling drove the species down to roughly 400 animals in the early twentieth century; the population has since rebounded to around 15,000. But recovery has been uneven across regions, and researchers note that warming seas and shrinking Antarctic sea ice are reducing krill — a staple food — with links to lower birth rates and reduced female condition in some populations.

What the scat actually revealed

Using DNA metabarcoding — molecular tools that identify prey from genetic fragments — Ph.D. student Aashi Parikh and colleagues found that these whales eat a far broader menu than the textbook "krill and copepods" picture. Across every sampling location, the most commonly detected prey were the small, likely juvenile stages of crabs, shrimp, and lobsters. Jellyfish and mantis shrimp turned up too. Krill, by contrast, were rarely detected directly in the scat.

Here's the twist that makes the study worth a paleontologist's attention: while krill were scarce in the droppings, they left a lasting fingerprint on the whales' gut microbiome. The bacterial communities inside the animals reflected long-term diet rather than the last meal, suggesting krill still matter greatly at other times and places. Associate Professor Emma Carroll framed the results as cautiously hopeful — the whales appear dietary flexible, which may help them cope as climate change reshuffles Southern Ocean prey.

Why this matters for fossils

Diet is one of the hardest things to reconstruct from an extinct animal. A skeleton tells you the machinery — jaw shape, tooth or baleen anatomy, body size — but not what actually went down the throat. This study shows that even for a living whale, our anatomical assumptions can miss the mark: everyone "knew" right whales were krill and copepod specialists, and the scat says otherwise. That should make anyone reading feeding habits off a fossil skull a little more humble.

South Carolina is one of the best places on the planet to appreciate that problem, because the Charleston area preserves the birth of filter feeding itself. The late Oligocene Chandler Bridge Formation and the older Ashley Formation have produced globally important early whales, including Coronodon, a toothed mysticete whose broad, slotted cheek teeth have fueled debate about whether it strained or sliced its food, and Ankylorhiza tiedemani, a large predatory early dolphin relative. These animals document the messy transition from toothed ancestors toward the baleen-bearing giants we know today. We can measure their teeth and jaws to the millimeter — but the new tohorā work is a blunt reminder that the actual diet may have been broader, weirder, and more opportunistic than any single skull suggests.

A living right whale off our own coast

The South Carolina angle isn't only deep-time. The study's subject has a critically endangered northern counterpart, the North Atlantic right whale (Eubalaena glacialis), which uses the waters off Georgia, northern Florida, and the South Carolina coast as its primary winter calving ground. Fewer than roughly 400 remain — eerily close to the low point the southern species clawed back from. So while Lowcountry collectors are used to thinking about whales as fossils weathering out of blackwater riverbanks and Oligocene marl, right whales are also present-tense neighbors passing offshore each winter.

Balaenids — the right and bowhead whale family — have a fossil record extending back into the Miocene and Pliocene, later than the archaic Oligocene whales of the Ashley and Chandler Bridge. That makes the modern research a useful bracket: it tells us how a specialized filter feeder behaves in the real ocean, and how sensitive its reproduction is to prey supply. Applied backward, it hints at how climate swings across the Neogene may have pushed whale communities to shift diets and ranges — the same kinds of shifts that helped shape the fauna now entombed in South Carolina's marine units.

The takeaway for collectors

Two things are worth carrying away. First, unglamorous evidence — a grapefruit-sized lump of whale scat kept in a freezer by a persistent amateur — can crack open a scientific question that formal expeditions had left unanswered. That's a good creed for any fossil hunter walking a Cooper River ledge or an Edisto gravel lag: the mundane-looking find can be the important one. Second, feeding behavior is genuinely hard to know, whether the animal is alive today or 25 million years gone. When you hold an Oligocene whale tooth or a fragment of fossil baleen-bearing jaw, it's worth remembering that the diet it implies is a hypothesis, not a receipt.