A Cuvier’s beaked whale achieved a new deep-sea diving record with a two-mile plunge into the dark recesses of the Pacific Ocean. This champion whale was one of eight who have been tracked by satellite-linked tags for a long-term study of the elusive creatures. The beaked whales are heralded for their paramount diving capabilities, but it was not known until recently just how remarkable their skill is. The new study is a first look at these animals’ impressive diving patterns.
The beaked whale is extremely difficult to observe according to Randall Davis, marine mammal biologist at Texas A&M University. The whales characteristically spend most of their time far from the shore and some of the species are only known by the carcasses that wash up to the shore. Davis says Cuvier’s beaked whale may be the most well-known of the species. With the help of the new study, researchers are able to compile data and get a more detailed look into their mysterious ways.
The scientists have been observing the whales in their search for food for several months and documenting their diving behavior. Since the start of the study, more than 3,700 hours have been spent collecting the data of more than a thousand dives descending nearly a mile into the sea. More than one of the dives challenged the current record held by any sea mammal, which previously was the southern elephant seal, with a mile-and-a-half dive lasting 120 minutes. The new research has awarded the record to the beaked whale, who dove two miles down into darkness during a 137-minute descent.
Davis, who is not part of the study, calls this record-setting dive depth “spectacular.” His suspicion is that the animals are deep-diving in search of deep-sea squid, which must be a worthwhile endeavor. The conditions are so extreme that if they had not found what they were seeking, the animals would forego the plunge. Two miles under water, the water pressure is a debilitating 4,707 pound per square inch, which is equal to 320 atmospheres. Davis says at such great depths, air-filled spaces in the body, like the lungs, are in danger of collapsing, and there is also a possibility the nervous system will be subjected to spontaneous convulsions related to high-pressure nervous syndrome.
The 10,000-foot record-breaking dive achieved was such a shock to the research team that they tested an identical tag to double-check its accuracy at such extreme deep sea depths. It was nearly inconceivable that the animals could still function so far below the surface, yet Cuvier’s beaked whales have demonstrated numerous dives over thousands of feet without developing any side effects. The whale’s skeletal structure is constructed with a collapsible rib cage, which also collapses the lungs, providing a major reduction in air pockets, describes Davis, but it is still a mystery how the whales circumvent high-pressure nervous syndrome. Researchers plan on tackling many of the mysteries that studying the mammals has revealed, but for now they are concentrating on accruing basic behavioral observations. The team says the most prevailing behavioral pattern is one single plunge followed by a sequence of shorter dives, with only a few minutes of recovery spent at the surface between dives. Scientists also recorded 5,600 shallow dives, averaging .17 miles.
A Cuvier’s beaked whale may also hold the title for longest breath held among marine animals. Dr. Gregory Schorr, lead scientist in the study from the Cascadia Research Collective, the Washington-based non-profit organization leading the new research, says one of the most remarkable aspects of the whale’s ability to dive to such depths is that at the dive’s furthest point, the whale is literally miles away from its mammalian, physiological need: air.
Erin Falcone, a fellow research biologist with the Cascadia Research Collective, explains that beaked whales have extremely high levels of myoglobin protein in their muscles, which functions similarly to hemoglobin in the blood, storing high levels of oxygen. With this advantage, the whales do not need to breathe as regularly. She credits the animals’ reduced amount of air pockets in the body to its diving success and “crush resistance,” adding, “It is the presence of air spaces within the body that would crush a human at a fraction of the depths these whales can dive.”
Another interesting component of the study is its proximity to a Navy sonar testing area, because Cuvier’s beaked whales are suspected to be sensitive to military sonar. Schorr says the team is studying the whale’s behavior in response to the military activity in southern California. “That’s an advantage to these long-term studies,” he says. “We can look at how long any impacts last and how long it takes [the whales] to get back to normal behavior.”
Perhaps, since the whales are still able to descend to such extraordinary depths, it may mean they have grown accustomed to the sonar. Erin Falcone, however, still proceeds with caution. She wants to take advantage of conducting the study in one of the world’s most heavily used sonar training areas. Gathering information regarding the whale’s assumed sensitivity to sonar activity will help the scientists understand how the beaked whales have been affected in this area and increase the probability of more record-setting deep-sea dives being achieved and recorded in other places.
By Stacy Feder