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Shhhh! It’s a Whale Nursery!
Giving birth in shallow-water areas may protect southern right
whale calves from predators. Credit: NOAA
Deciding where to have their baby is an important aspect of birth
planning for many expectant mothers. Southern right whale mothers
also take their birthing location very seriously, traveling thousands of
miles to shallow-water sites before giving birth to their their calves. It
turns out, these whale moms have a very good reason for these long
migrations: the shallow water provides a safe harbor where it’s more
difficult for predators to find them and their calves.
A trio of biologists at Syracuse University recently looked into why southern right whales pick these shallow nurseries along the coasts of Brazil, South Africa, and Australia. The clues were in the acoustics of these nursery areas.
Like all whales, southern right whales make sounds to communicate with one another. Often these sounds travel quite far, which is useful for large whale pods that need to communicate over long distances. But when they have vulnerable, young calves to care for, such long-ranging sounds may attract predators. Shallow, sandy nursery areas have poor acoustics, making it harder for whales to hear each other, unless they’re in very close proximity. But if they can’t hear each other except at close range, that means potentially hungry hunters can’t eavesdrop on them either.
The scientists found that the depths where the mothers and their calves spent the most time were also the depths where their sounds traveled the shortest distances—no matter what part of the world they were in. In coastal waters less than 10 meters deep, their calls couldn’t be heard more than 500 meters away. Yet in deeper waters, the calls of right whales can travel 30 to 100 km away. The limited acoustic range of shallow waters may protect young whales from predators and even other whales.
A trio of biologists at Syracuse University recently looked into why southern right whales pick these shallow nurseries along the coasts of Brazil, South Africa, and Australia. The clues were in the acoustics of these nursery areas.
Like all whales, southern right whales make sounds to communicate with one another. Often these sounds travel quite far, which is useful for large whale pods that need to communicate over long distances. But when they have vulnerable, young calves to care for, such long-ranging sounds may attract predators. Shallow, sandy nursery areas have poor acoustics, making it harder for whales to hear each other, unless they’re in very close proximity. But if they can’t hear each other except at close range, that means potentially hungry hunters can’t eavesdrop on them either.
The scientists found that the depths where the mothers and their calves spent the most time were also the depths where their sounds traveled the shortest distances—no matter what part of the world they were in. In coastal waters less than 10 meters deep, their calls couldn’t be heard more than 500 meters away. Yet in deeper waters, the calls of right whales can travel 30 to 100 km away. The limited acoustic range of shallow waters may protect young whales from predators and even other whales.