There are some areas in the world where organisms inhabit areas that are so secluded and difficult to reach that it is almost impossible to study them in their natural environment. Beaked whales are one of them, with 24 species confirmed to date. These mammals live in deep waters far from the coast and dive to the bottom of the ocean at depths of more than 500 meters in search of food.
Recent studies have upended conventional wisdom about the Baird's beaked whale, finding that its population thrives in shallow coastal waters near the Commander Islands. This adaptation highlights the importance of understanding the different behaviors and habitats of whale species for effective conservation efforts. Source: Olga Filatova, University of Southern Denmark
The holder of the record for the deepest dive of a mammal is the Couvel-beaked whale, which was measured to have dived at least 2,992 meters in 2014. The beaked whale also holds the record for the longest dive time in a mammal: 222 minutes.
Now, through the scientific study of a population of Baird's beaked whales, the world has gained a new and surprising understanding of the distant world of beaked whales. This population was unexpectedly found near the coast and is located in shallower waters than previously observed.
The study, led by whale biologists Olga Filatova and Ivan Fedutin from the University of Southern Denmark/Fjord & Belt, was published in the journal Animal Behaviour.
The two researchers have been studying whales in the North Pacific for many years, and in 2008, during an expedition to the Commander Islands, they saw a pod of shellfish-beaked whales off the coast for the first time.
"We were there looking for killer whales and humpback whales, so we just noticed that we saw a pod of shelly's beaked whales and didn't do anything. But in the following years, we also saw them, and five years later, we suspected that it was a stable community that frequented the same area. "We were able to see them every year until 2020, when COVID-19 prevented us from returning to the Commander Islands," explains Olga Filatova, a whale expert at the Department of Biology at the University of Southern Denmark and the SDU Climate Group. "
A Baird's beaked whale near the Commander Islands. It can be seen that there are two teeth in the lower jaw. The body is covered with scars from fights with other beaked whales. Image credit: Olga Filatova, University of Southern Denmark.
Coastal habitat and whale behavior
The population of beaked whales studied is close to shore - within four kilometers of land, and they are observed in shallow water, at a depth of less than 300 meters.
"This is unusual for this species," Olga Filatova said. It is likely that this group has adapted to this particular habitat and thus deviated from the established notion that all beaked whales swim in the open and deep seas. This means that all individuals in a particular species cannot be expected to behave in the same way. This makes it difficult to develop a species conservation plan – for example, in this case it cannot be made on the assumption that beaked whales only live far out of the deep sea. We have shown that they can also live in shallow and coastal waters. There may be other different habitats that we are not yet aware of. "
There are many examples where individuals of the same species of cetacean do not behave in the same way. In the world of whales, it is not uncommon to see groups of the same species living in different places, eating different prey, communicating in different ways, and not liking to interact with their own kind from other groups.
Baird's beaked whale in the Commander Islands. Source: Olga Filatova, University of Southern Denmark
Some killer whale pods only hunt marine mammals such as seals and porpoises, while others only hunt herring. Some humpback whales migrate between the tropics and the Arctic, while others inhabit certain areas. Some sperm whale groups develop their own dialect for internal communication and do not like to communicate with other whales outside the group.
Olga-Filatova argues that social learning comes into play when groups develop preferences for things like habitat and prey. Social learning in the animal world takes many forms. Imitation is the most complex form, and when animals see what others do, they understand the motives and reasons behind them. There is also "local fortification", in which an animal sees another animal going to a particular place, and then follows it, thus learning that the place is valuable. This phenomenon occurs in many animals, including fish.
The cultural tradition of beaked whales
Olga Filatova believes that the population of Bey's beaked whales on the Commander Islands was learned through "local fortification": they saw some companions come to the shallow waters near the coast, followed them, and found that it was a good place, probably because there were a lot of fish there. This became a cultural tradition, and it was also observed for the first time in beaked whales.
Other examples of whale cultural traditions include whale formation of specific hunting traditions: some whales stun schools of fish with their tails, some whales set off waves to wash seals off the ice floe, and some whales chase fish onto the beach.
From 2008 to 2019, researchers observed a total of 186 Baird's beaked whales in the Commander Islands. Of these, 107 were observed once and were therefore assessed as transient whales. Seventy-nine were found more than a year ago and were therefore assessed as resident whales.
There were 61 short-stay whales seen interacting with residents, 7 of which were seen in shallow waters.
"Transient whales are not as familiar with the local area as residents, and as a result, they often seek out food at the normal depths of their species. But in reality, we observed some transient settlers in the shallow waters. These individuals have some form of social contact with the inhabitants. "It must have been in this contact that they learned about shallow waters and their advantages," Olga-Filatova said. "
It's unclear how many Baird's beaked whales there are in the world.
编译来源：ScitechDaily