As Humpback Whales Migrate to Antarctica, One Straggler Washes Ashore in the Amazon

Last Friday, researchers from the Brazilian conservation group Bicho D’Água spotted a group of vultures circling a mangrove on the remote island of Marajó. Upon arriving to take a closer look, the team made a startling discovery: As Matthew Haag writes for The New York Times, the scavengers were feasting on the carcass of a 26-foot-long humpback whale calf—an unusual sight given the fact that at this time of year, the whale should’ve been some 4,000 miles away in its seasonal Antarctic feeding grounds.

Speaking with Brazilian news site O Liberal, Bicho D’Água marine biologist Renata Emin offered a possible explanation for the calf’s presence, explaining, “We’re guessing that the creature was floating close to the shore [when] the tide, which has been pretty considerable over the past few days, picked it up and threw it inland.”

Still, the Independent’s Tim Wyatt points out, it remains unclear why the whale was so far inland, let alone roaming the northern Brazilian coast. Although humpback whales typically congregate around the country’s southern Bahia coast during the August through November breeding season, it’s rare for the creatures to journey north toward the mouth of the Amazon River.

Haag of The New York Times further notes that during the Southern Hemisphere’s summer, humpbacks migrate to the Antarctic’s warmer polar waters, abandoning the equatorial region of Brazil until the hemisphere’s winter months.

It’s likely the beached calf was separated from its mother during the whales’ mass migration south, Aamna Mohdin reports for the Guardian. Experts estimate the unlucky creature was about 12 months old—as the Epoch Times’ Louise Bevan writes, this is around the age when calves tend to depart from their mothers.

According to Bevan, the current leading hypothesis posits that the whale died at sea and was thrown about 50 feet inland by rough currents and high tides. Photographs of the scene offer few discernible clues to the calf’s cause of death, but as Bicho D’Água biologist Emin tells Brazilian news site G1, researchers are pursuing several lines of investigation: In addition to checking the calf for marks that could indicate whether it was trapped in a net or hit by a boat, the team is waiting on a necropsy report that should be ready within the next 10 days.

In the meantime, the Maritime Herald has raised at least one potential cause of death, suggesting that the calf died after ingesting plastics found in its marine environment. As EcoWatch reports, this is becoming an increasingly common occurrence across the world. Last November, a sperm whale washed up in Indonesia with nearly 13 pounds of plastic in its stomach.

Peter Evans, director of the British-based Sea Watch Foundation, shares an alternative theory with the Guardian’s Mohdin: “This calf probably got separated from its mother, maybe its mother had died, in the southern summer, and then wandered about trying to find food,” he says. “The idea that it was killed by ingesting plastic would need some evidence first to support it. It seems to me more likely that it simply starved to death.”

Unfortunately, the Telegraph’s Ryan Walker points out, it’s possible scavenging and decomposition that took place between the whale’s death and its discovery could hinder scientists from reaching definitive conclusions on its unusual fate.

Given the sheer size of the calf—despite the fact that it’s roughly half the size of an adult humpback, the whale still weighs a staggering 10 tons—and remote nature of its resting place, authorities plan on leaving the carcass largely intact. The creature’s skeleton, according to the Independent’s Wyatt, will be dismantled, preserved and sent to a natural history museum in the nearby city of Belem.

Meilan Solly | | READ MORE

Meilan Solly is Smithsonian magazine's associate digital editor, history.