"Weird" Pygmy Whale Dissected
Dave Hansford in Wellington, New Zealand
for National Geographic News
|May 7, 2008|
A young pygmy right whale that stranded itself in New Zealand has given scientists a rare chance to study the little-known species.
The 7.5-foot-long (2.31-meters-long) specimen, probably a six-month-old male, was found dead at Spirit's Bay in the country's far north. (See a New Zealand map.)
Pygmy right whales, the world's smallest baleen whales, can reach lengths of up to 21 feet (6.5 meters), said Anton van Helden, a marine mammal scientist at the Museum of New Zealand Te Papa Tongarewa.
Paleontologists and anatomists from New Zealand, Australia, and the United States met at Te Papa to begin dissecting the whale—only the second ever examined—on Tuesday.
Updates posted today on the museum's blog suggest that the young animal carried scars from tiny cookie-cutter sharks.
The team was also surprised to find that the whale had hair on its body. Most whales lose their hair within a few weeks of birth, the blog posting said.
The scientists will pay careful attention to the animal's skeleton and larynx, which they believe may offer clues to its evolution.
(See photos from the first in-depth look of a colossal squid examined at the same museum.)
Pygmy right whales were first identified as a species from a piece of baleen in 1846.
The animals seem to inhabit the Southern Hemisphere, and most sightings and strandings occur in Australia and New Zealand.
A few individuals were taken by whalers in the 1960s and 1970s, according to team member Catherine Kemper, curator of mammals at the South Australian Museum.
Yet no fossils of pygmy right whales exist, van Helden said.
"We know almost nothing. That's the difficult part of trying to determine their relationship to other whales," he said.
Van Helden also points out that the mammal has its own taxonomic family, so its common name is likely a misnomer.
Though called a pygmy right whale, the animals don't have much in common with any species of right whale, he said.
"It's really a superficial similarity the head looks like a tiny right whale, but the extraordinary thing is that once you get behind the head, they are no longer anything like one," he explained.
"They have flippers like a beaked whale, and their dorsal fin is so far back down the body that you think their pants have slipped down."
"In fact, they may be more closely related to rorquals, [a family which includes] the blue whale and fin whales."
Pygmy whales are also anatomical oddities, he said. For one thing, they have more ribs than other whales.
"They have up to 18 ribs a side, and as you go down the animal, once you get past the ninth rib, they flatten out and become sort of overlapping plates, which looks like armor plating."
Sentiel "Butch" Rommel, a biologist from the University of North Carolina, Wilmington, is part of the research team.
He said a similar rib arrangement has only been found in anteaters and pangolins, both land dwellers.
The team will take tissue samples for DNA analysis and comparison with other specimens.
"That will give us an idea of how many haplotypes [a type of genetic group] are out there, and if there's any mixing between populations," team leader van Helden said.
Team member Joy Reidenberg, of the Mount Sinai School of Medicine in New York, was particularly interested in the whale's larynx.
"It's different [than] all the other baleen whales These guys have asymmetry. The larynx has a sac on it, like all baleen whales, but the sac is off to one side, and that raises a couple of very interesting functional and evolutionary questions, such as how they generate sounds."
Reidenburg said the bizarre organ structure either represents an early ancestral form or a modern development.
(Related: "Evolutionary Oddities: Duck Sex Organ, Lizard Tongue" [October 23, 2001].)
"It's at one end or the other of the extremes of the evolutionary tree. We don't know yet because it's so weird."
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