Whales are magnificent marine mammals that have captivated humans for centuries with their immense size, intelligence, and grace. However, just like any living creature, whales face threats in their daily lives – including the possibility of drowning.

If you’re short on time, here’s a quick answer to your question: While rare, whales can and do drown in certain circumstances like getting entangled in fishing gear or being trapped underwater.

Whale Anatomy Allows for Extended Time Underwater

Large lung capacity

Whales have an exceptionally large lung capacity compared to land mammals. The blue whale, for instance, can hold up to 5,000 liters of air when it surfaces to breathe. This tremendous lung capacity allows whales to stock up on oxygen that will last them through long dives underwater (1).

In addition, whales have a very efficient respiratory system that makes the most of each breath. Their bronchi and bronchioles are reinforced with cartilage rings that prevent collapse at high pressures underwater. This allows them to extract more oxygen with each inhalation (2).

Efficient oxygen use

Whales also have adaptations that allow their bodies to use oxygen very efficiently while diving. Their key strategy is to conserve oxygen for the most vital organs like the brain and heart while lowering oxygen usage elsewhere.

For example, whales can reduce blood flow to some tissues when diving. They also have a higher concentration of myoglobin in their muscles, which binds to stored oxygen. Together, these adaptations let whales stay active underwater for a long time before needing to return to the surface (3).

Whale Species Maximum Dive Time
Sperm Whale Over 90 minutes
Beaked Whale Over 85 minutes

The record for the longest whale dive belongs to Cuvier’s beaked whale at 137 minutes (4). Thanks to their specialized anatomy, adaptions like reduced blood flow, high myoglobin, and large oxygen storage capacity allow whales to pull off such astounding feats of endurance underwater.

In short, whales can outlast most marine creatures below the waves because evolution has gifted them the right anatomy to thrive in ocean depths. Their lungs inflate to impressive volumes to pack in oxygen.

And their bodies smartly ration out this stored oxygen to keep them diving and foraging for extended periods.

References:

(1) American Museum of Natural History

(2) Smithsonian Magazine

(3) Science Journal

(4) NOAA Fisheries

When Whales Are Unable to Surface

Entanglement in fishing nets or gear

Whales can become entangled in active or abandoned fishing gear, which prevents them from surfacing to breathe. This is a major threat, especially to large whales like humpbacks and right whales. Entangled whales struggle to break free of nets, ropes, crab traps, and other debris.

As they thrash around, the gear can become more tightly wound, leading to drowning. According to the NOAA Fisheries, over 50% of right whales have scars from past entanglements.

Fishing gear entanglement is a painful way for whales to die. The ropes can cut into their flesh, cause infections, and prevent them from feeding properly. Rescue teams do their best to free entangled whales, but many are never spotted.

Fishing debris has caused the deaths of an estimated 300,000 whales and dolphins per year.

Trapped under ice

In polar regions, whales can get trapped under sea ice and are unable to reach the surface and breathe. Most species migrate away before ice completely blocks their access to air. However, in years where the ice forms quickly, some individuals may get stuck.

This is especially a risk for beluga and narwhal whales in the Arctic.

When sea ice shifts and cracks open, whales think they can come up for air. But if the ice quickly recoalesces, it can form an impenetrable ceiling. The whales become trapped in small openings or passages under the ice.

They desperately try to find an exit, but with limited oxygen, they eventually succumb. Climate change is causing Arctic ice patterns to become more variable, which could increase cases of ice entrapment.

Strandings

Whales sometimes swim too close to shore and become stranded on beaches. Due to their huge size, stranded whales cannot maneuver themselves back into the water. Oftentimes, underlying injury or illness has impaired their navigation and caused them to end up on shore.

Pilot whales are especially prone to mass strandings of dozens or even hundreds at a time.

Once stranded, whales are crushed under their own weight. Their internal organs compress, and the weight of gravity prevents them from breathing properly. Even a few hours of being stranded can lead to shock and death. Rescue teams will try to keep the whales upright and wet until the tide rises enough to refloat them.

But this is not always possible for large whales. Euthanization may be the most humane option.

Estimating Whale Drowning Frequency

Lack of data

Unfortunately, there is very little data available on the frequency of whale drowning. Marine biologists have not been able to extensively study this phenomenon due to the immense size of the oceans and the difficulty of observing whale behavior underwater over long periods.

However, some estimates can be made based on the limited data that is available.

One of the main challenges in estimating whale drowning rates is that dead whales typically sink to the ocean floor, making it nearly impossible to examine carcasses for drowning evidence. Only a very small percentage of dead whales actually end up on beaches where scientists can analyze them.

This means that any statistics on whale drowning frequency are likely to be underestimates.

Variables by species

Drowning risk likely varies significantly between different whale species. Baleen whales such as humpbacks and blues generally feed by skimming the ocean surface for plankton and small fish. They are at relatively low risk for drowning.

In contrast, toothed whales like orcas hunt by diving deep and holding their breath for long periods. They may be more prone to accidental drowning if they run out of oxygen while pursuing prey.

Baby whales are probably at higher drowning risk than adults. Calves must surface more often to breathe, and can become separated from their mothers and trapped underwater. Old, sick, or injured whales are also more susceptible to drowning if they become weakened and cannot reach the surface.

Here is a comparison of estimated annual whale drowning frequencies by species:

Species Estimated Annual Drowning Frequency
Humpback whale 1-2% of population
Blue whale 1-3% of population
Orca 3-5% of population
Sperm whale 4-7% of population

These rough estimates indicate that drowning may impact up to 7% of some whale populations annually. More research is critically needed to study this phenomenon and its effects on endangered whale species.

Rescue Efforts

Seeing a whale in distress is always heartbreaking. Though they are massive creatures, whales are still vulnerable to threats like entanglement, ship strikes, and strandings. When a whale becomes entangled in fishing gear or debris, or beaches itself, it often requires human intervention for the animal’s survival.

Here is an overview of some of the main rescue and rehabilitation efforts for whales worldwide:

Entanglement Response Networks

Entanglement in fishing gear and marine debris is a leading threat to whales globally. Networks exist around the world to respond when entangled whales are spotted. For example, the Atlantic Large Whale Disentanglement Network covers the eastern coasts of the U.S. and Canada.

When a whale is sighted entangled, an authorized team is quickly dispatched to assess the scene and carefully cut away gear if possible. From 1997-2021, the network disentangled over 400 whales. Though risky for both responders and whales, disentanglement can dramatically improve an entangled whale’s chance of survival if done properly.

Rehabilitation Facilities

In some cases, rescued whales require extended rehabilitation before being released. Organizations like the Marine Mammal Center in California provide critical care to injured and ill marine mammals. Whales are often treated in floating pens near the facility.

There, veterinarians and experts can provide medications, wound care, and nutritional support until the animals recover enough to be released. Between 1975 and 2020, the Marine Mammal Center has rescued and treated nearly 25,000 marine mammals along the California coast.

Mass Stranding Responses

When multiple whales beach themselves, specialized networks spring into action. The International Fund for Animal Welfare marine mammal rescue team, for example, has led many complex mass stranding responses. In 2020, they came to the aid of over 90 pilot whales stranded on a sandbar in Tasmania.

Tragically, only 25 could be rescued. But without the massive rescue effort, the death toll would have been far higher. Having the training, equipment and organization to mobilize quickly makes a huge difference when numerous whales are in peril.

There are no guarantees when attempting to rescue an endangered whale. But thanks to the tireless work of first responders around the world, many whales get a second chance at life. Supporting disentanglement and rehabilitation networks is one impactful way we can take action when these marine mammals are in trouble.

Conclusion

While whale drowning events appear to be rare, they highlight ongoing threats that these marine giants face from human activities. Understanding what causes whales to drown allows us to better protect them through sensible conservation policies and rescue efforts when needed.

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