Dried Meat ‘Resurrects’ Lost Species of Beaked Whale

sn-whales

A gift of dried whale meat—and some clever genetic sleuthing across almost 16,000 kilometers of equatorial waters—has helped scientists identify a long-forgotten animal as a new species of beaked whale. The “resurrection” raises new questions about beaked whales, the most elusive and mysterious of cetaceans.

“Literally nothing is known about most species of beaked whales; they are probably the least known family of large mammals,” says Robin Baird, a cetacean biologist at Cascadia Research Collective in Olympia. “So it’s exciting to have this study.”

The species, Mesoplodon hotaula, is a dark blue, Volkswagen-van-sized cetacean with the prominent snout that gives beaked whales their common name. It first came to scientists’ attention in 1963 when a single adult female stranded on the coast of Sri Lanka in the Indian Ocean. The director of the National Museums of Ceylon, P. E. P. Deraniyagala, decided that it was different from the other Mesoplodon species known at that time, and assigned it the name hotaula, meaning “pointed beak” in the local Sinhala language. But only 2 years later, M. hotaula was eliminated as a species when other researchers decided that it was identical to M. ginkgodens (another beaked whale which scientists know only from stranded carcasses and have never seen alive in the sea).

Forty years later, locals on an atoll in the Gilbert Islands, part of the Republic of Kiribati in the west Pacific, gave a visiting marine biologist dried strips of whale meat left over from a recent festival. The sample was turned over to cetacean geneticists at the University of Auckland in New Zealand who had assembled a database of the DNA of all known beaked whales. “It was a surprise, because the genetic sequences from the meat didn’t match any of the known species,” says Scott Baker, a cetacean geneticist now at Oregon State University’s Marine Mammal Institute in Newport, and one of the authors of the study. “We thought we had a new species.”

Then, in 2005, other co-authors collected some whale bone and teeth on Palmyra Atoll, which lies southeast of the Hawaiian Islands and 2600 kilometers northeast of the Gilbert Islands. The genetic sequences extracted from these specimens matched those of the dried meat. “We knew then we were on to something,” Baker says. Finally, in 2009, the body of a beaked whale was found in the Seychelles, in the western part of the Indian Ocean; its DNA also matched that of the dried meat sample, even though this whale lived tens of thousands of kilometers away from the Gilbert Islands.

That was the clue the researchers needed. “We immediately wondered, ‘Could it be Deraniyagala’s beaked whale?’ ” Baker says. It was. The team recently reported its resurrection of the forgotten M. hotaula in Marine Mammal Science. Counting M. hotaula, there are now 15 known species in this genus, making it by far the most species-rich genus of cetaceans.

Overall, the saga of M. hotaula shows “that there are probably even more species of beaked whales that we don’t know about,” says Phil Clapham, a marine mammalogist at the National Marine Mammal Laboratory in Seattle, Washington. “We don’t see them because they’re very deep-diving and live far from land.” They also live in a poorly surveyed part of the ocean, Baker says, where very few people dwell on remote atolls.

Intriguingly, it is the islanders who seem to know the most about M. hotaula and some other beaked whales. The Gilbert Islands residents who provided the original gift of dried meat reported that it came from one of seven whales they had driven onto the beach and killed. “That was something we didn’t know: that these beaked whales live in groups,” Baker says. “We thought they were solitary” because of the single, stranded individuals that are occasionally found. The scientists also believe that males of M. hotaula fight each other, because this behavior is known in other species of beaked whales, and because the teeth of two adult male specimens were broken. “Other than that, and knowing that Deraniyagala was right, M. hotaula is still pretty mysterious,” says Baker, who hopes to launch an expedition to learn more about them.

http://news.sciencemag.org/biology/2014/02/dried-meat-resurrects-lost-species-whale

Thanks to Dr. Rajadhyaksha for bringing this to the attention of the It’s Interesting community.

Blue whales perform underwater acrobatics to attack their prey from below

 

The massive mammals are known for lunge-feeding; gulping up to 100 tonnes of krill-filled water in less than 10 seconds.

Using suction cup tags, US researchers have recorded the surprising manoeuvrability of the giants.

They found that the whales roll 360 degrees in order to orientate themselves for a surprise attack.

The results are published in the Royal Society journal Biology Letters by Dr Jeremy Goldbogen and colleagues for the Cascadia Research Collective based in Washington, US.

“Despite being the largest animals to have ever lived, blue whales still show an impressive capacity to perform complex manoeuvres that are required to efficiently exploit patches of krill,” said Dr Goldbogen.

Blue whales feed exclusively on krill: small crustaceans that have excellent escape responses, requiring the mammals to have efficient foraging strategies to be able to meet their energy demands.

To understand how these giants manage to capture prey, despite their size reducing their mobility, Dr Goldbogen and his team tagged a group of animals off the coast of southern California, US.

Using suction cups to safely attach the acoustic recording tags without harming the animals, the team were able to track the whales’ movements with the help of underwater microphones.

Results revealed that the whales were executing impressive spins below the waves in order to access large patches of krill.

“As the blue whale approaches the krill patch, the whale uses its flippers and flukes to spin 180 degrees so that the body and jaws are just beneath the krill patch,” explained Dr Goldbogen.

“At about 180 degrees, the mouth just begins to open so that the blue whale can engulf the krill patch from below.

As the blue whale engulfs the prey-laden water, it continues to roll in the same direction and completes a full 360 roll and becomes horizontal again ready to target and attack the next krill patch.”

The researchers were able to record video footage of the impressive acrobatics using a video camera worn by another animal to capture natural behaviour.

“We did not expect to see these types of manoeuvres in blue whales and it was truly extraordinary to discover,” said Mr Goldbogen.

Previous research has identified similar behaviour in other rorqual whale species such as humpback whales, but these animals rarely exceed 150 degree turns.

In these smaller whale species the ability to twist and turn was attributed to long fins and tail flukes.

For blue whales however, scientists suggest the extra effort of turning rewards the massive mammals with enormous meals.

They also propose that the acrobatics optimise the animals’ field of view.

“As in all cetaceans, [blue whales’] eyes are positioned laterally, and thus rolling the body should enhance panoramic vision in multiple dimensions,” the study reported.

Dr Goldbogen commented that the results will fuel further research into the complex behaviour of whales, especially regarding predator-prey interactions.

“This extraordinary ability is only a glimpse into the diverse repertoire of manoeuvring behaviours performed by foraging animals,” he told BBC Nature.

“Future tagging work has the potential to reveal many more unique insights into the daily lives of animals in their natural environment.”

http://www.bbc.co.uk/nature/20509831