Page 94 - World of Animals - Book of Sharks & Ocean Predators

Sharks & Ocean Predators
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There was once a time when the oceans were thought to mates or repelling rivals,
be vast expanses of virtual silence, but we gradually began but it has something to
to realise that our planet’s water bodies were a cacophony do with mating.”
of aquatic noise. When biologist Roger Payne discovered The noises that the
the song of the humpback in the late 1960s, everything we whales string into their
thought we knew changed. Yet, over four decades on, we eerie performances
still don’t know the full story and the whales are keeping are generated as they
scientists guessing. force air through their
Humpbacks are large whales, reaching up to 15 metres nasal cavities “sort
(50 feet) in length. These majestic beasts have long, of like a bagpipe”,

tapered bodies with elongated pectoral fins and a short Asmutis-Silvia explains.
dorsal fin, ending in a large fluked tail. Their knobbly heads “They produce a low-

have huge jaws to help with their filter-feeding method of frequency sound and
eating. “They’re found in all oceans, but not necessarily all the lower the sound,
of the time, because they’re migratory,” explains Regina the further it will travel,
Asmutis-Silvia, executive director of the North American so they can conceivably
Whale and Dolphin Conservation Society. “They tend to communicate with other
go to higher latitudes to feed, then to the more-temperate whales that are tens if not
tropical waters for breeding.” hundreds of miles from them,”
For whales that cruise across whole oceans every she continues. “It’s kind of like
year, tracking them down for study can be tricky. This is a mobile phone – you can stay
one reason why we don’t know much about their social connected with your family even
structures, or their amazing methods of communication. when you can’t see them.” The whales’
Like most cetaceans (the group of animals containing keen hearing means the animals can be in
whales and dolphins), humpbacks make grunts, whines touch across huge expanses of ocean.
and shrieks. However, their songs have been dubbed as So, why do the males sing at all? “It was
the most-complex vocalisations in the animal kingdom and thought to happen only in the breeding area or
are truly captivating. maybe the shoulder seasons,” Asmutis-Silvia continues. ABOVE Humpback whales adopt a
“[Humpback] song is made up of many sounds that “But it seems to be happening year-round, so it has some very specifi c stance before beginning
the whales arrange into long, complex songs each year,” function that isn’t exclusive to breeding. It may be a their serenades
says Dr Ellen Garland, from the National Marine Mammal contact call – it may have different purposes at different
BELOW The underwater songs have
Laboratory. “It’s an acoustic display that’s produced by locations as well.” When the males do sing, they seem to set patterns, but to impress females,
males. We aren’t quite sure whether it’s for attracting find one another, as Asmutis-Silvia goes on: “[A whale] will males will o en vary their tunes

HUMPBACK WHALE
Megaptera novaeangliae
Class Mammalia

Territory Found in all the
world’s oceans
Diet krill, plankton, small fi sh
Lifespan 45-50 years
Adult weight 40 tons
Conservation status

LEAST CONCERN

“Their songs have been dubbed as the most-

complex vocalisations in the animal kingdom”

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