Among the many charming activities of beluga whales is their propensity for blowing bubbles. But expelling breath underwater is a curious behavior for a creature that spends a lot of time holding its breath for a living.
Researchers from Canisius College, led by animal behavior professor Michael Noonan, wanted to understand just why they'd blow bubbles. So they spent eight years and 5,000 minutes observing beluga whale "bubbling events" at Marineland of Canada, in Niagara Falls, Ontario.
It turns out the bubbles may be an expression of their mood.
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For starters, the scientists learned that nearly all bubbles blown by beluga whales fall into just four shape types: blowhole drips, blowhole bursts, blowhole streams and mouth rings.
The kicker about delineating those particular shapes was that each corresponded to certain type of mood.
For example, the researchers found, the whales tended to make blowhole drips and mouth ring bubble shapes when they were being playful - most often done by the female belugas. The latter observation suggested to the researchers that female belugas may be a bit more playful than males.
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Meanwhile, adult female belugas also made blowhole burst bubbles more frequently than the males. The blowhole burst is thought by the scientists to be a startle reaction, "which suggests that adult females are more reactive by nature than adult males," said Noonan, in a statement.
Curiously, though, in the youngins' it turned out that juvenile males made blowhole burst bubbles more often than the young ladies. That, said Noonan, "reflects a rowdier level of play bouts in younger males than females."
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When it came to blowhole streams, the scientists observed them most often in the males - adult and juvenile. The behavior is thought to be an expression of aggression in humpback whales, but in belugas it's a bit less clear-cut, according to the researchers.
While it was true that the streams were made most often by males, Noonan said he and his team only infrequently witnessed overt aggression among the whales under study.
"More typically," Noonan said, "we saw Belugas produce blowhole streams when two whales were parallel swimming in an amicable fashion."
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Other nifty facts that bubbled to the surface in the beluga whale study:
They blow an average of 58 bubbles per minute.
Almost 90 percent of bubbles come from the blowhole, the remainder through the mouth.
The team also found that sometimes there just were no bubbles.
"In working with these animals, we definitely found that there were ‘bubble days' and 'non-bubble days,'" said Noonan.
"A contagious effect, in which the bubbling of one Beluga stimulates or at least facilitates a similar bubble release by another whale, could explain the occurrence of extremely high bubble days at frequencies greater than that predicted by chance," he added.