Why Do Whales Explode?

Whales can explode due to the build-up of internal gases from decomposition after death. Bacterial action inside the whale's body produces gases that can cause the carcass to rupture.

By Bertie Atkinson - Science & Biology Editor
Why Do Whales Explode Cetacean stranding

It’s sadly common to see in the news that a whale or a large cetacean has stranded on the beach. Regrettably, many of them die because they are unable to get back into the water, even with human assistance. Their skin is highly sensitive, and the weight it bears doesn’t allow them to withstand the environmental conditions on the surface.

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A stranded whale can result from certain behaviors, such as seeking refuge near the shore to escape danger in deep waters. Poor weather conditions can also attract cetaceans to the beaches. But there’s an anthropogenic reason as well. The sound emitted by boats in the oceans can interfere with the whales’ sonar, disorienting these marine mammals, making human technology a factor to consider when trying to understand why whales strand.

There can be health risks associated with exploding whales, as the release of bodily fluids and gases may contain bacteria and other contaminants. Safety measures are taken during necropsies and clean-up efforts.

Why Do Whales Explode?

Even though an animal dies, a part of its body continues to live, particularly the digestive system. Both the stomach and intestines host microbial reproduction linked to the body’s decomposition. This process generates gases such as methane and hydrogen sulfide.

When you see a stranded whale on the beach, you may notice that, as the hours pass, the whale’s body appears to inflate. This is not just a perception; it’s entirely accurate. The carcass begins to swell due to gases produced by the decomposition of the body. These gases originate from the bacterial activity of the whale’s natural gut flora.

This post-mortem bacterial activity can be highly variable, depending on factors like the type of bacteria involved, the cause of the whale’s death, pre- and post-mortem injuries, and the type and quantity of food in its stomach. It’s also influenced by the environmental conditions surrounding the whale.

Bacterial activity and the rate of decomposition slow down in lower temperatures, which would occur in the water. However, on a beach with warm temperatures, decomposition and gas production increase significantly.

When the inflated body of a whale undergoes mechanical stress, such as being lifted by a crane from the beach, gases and liquids exert pressure on the body’s walls. This is how a whale can eventually explode on the beach.

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Famous Whale Explosions

Throughout history, several whale explosions from stranded carcasses have occurred in different parts of the world. Here are a few of the most famous cases:

1970 Oregon Whale Explosion

This is perhaps one of the most famous whale explosions. In the 1970s, a massive sperm whale weighing between 40 and 65 tons washed ashore on a beach in Oregon, USA. Authorities faced a daunting task in removing the colossal carcass. In an attempt to dispose of it, they placed dynamite near the whale’s body, hoping to break it into smaller, more manageable pieces. However, the explosion was far more powerful than anticipated, and bits of the whale were propelled over a wide area, including onto bystanders and buildings.

Taiwan City-Exploding Whale (2004)

Taiwan City-Exploding Whale (2004)
Taiwan City-Exploding Whale (2004). Image: NBC News.

In 2004, a stranded and deceased whale in Taiwan exploded in the heart of the city during transportation to a research facility. The buildup of gases inside the animal, combined with the physical stresses during transport, led to a sudden and messy detonation. The explosion resulted in a bizarre and unpleasant scene, with bystanders, vehicles, and storefronts being splattered with decomposing whale remains.

New Zealand’s 2017 Pilot Whale Strandings

New Zealand's 2017 Pilot Whale Strandings
New Zealand volunteers formed a human chain to rescue the surviving whales. Image: Smithsonian Mag.

In 2017, New Zealand witnessed a massive stranding of approximately 416 pilot whales. These strandings were highly publicized, not only for their tragic impact on marine life but also for the fear of potential explosions. Nearly 100 individuals were successfully returned to the water. To prevent these explosions, those whales that could not be rescued were subjected to incisions in their stomachs to release the gases. The bodies of these majestic marine creatures were then laid to rest in nearby sand dunes.

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