Humpback Whales Give Birth Much Farther South Than Previously Thought, Study Finds
Humpback Whales Give Birth Much Farther South Than Previously Thought, Study Finds
Researchers in Australia found records of humpback whale calves more than 900 miles farther south than expected
A mother and baby whale spotted swimming near Kiama, New South Wales, Australia.
Vanessa Risku / Instagram: droning_my_sorrows
Each year, humpback whales migrate predictably between cold, nutrient-rich feeding grounds and warm, tropical calving grounds, where they give birth and care for their young.
Or so scientists thought. Researchers in Australia recorded calves being born much farther south than previously thought, which challenges long-held assumptions about humpback migration patterns. They shared their findings in a new paper published yesterday in the journal Frontiers in Marine Science.
Humpback whaleslive in all of the world’s oceans. These behemoth marine mammals are highly migratory, swimming thousands of miles each year. The longest humpback whale migration ever recorded was 8,106 miles, from South America to Africa, though more typical distances are around 5,000 miles.
In the Southern Hemisphere, humpbacks head to the krill-rich waters of the Southern Ocean around Antarctica every summer, then venture up the eastern and western coasts of Australia toward the warmer waters north of the continent every winter.
Researchers long believed that humpbacks only gave birth to their calves in the tropical waters north of 28 degrees latitude on Australia’s east side and north of 23 degrees latitude on the west side.
“Our general concept of humpback whale ecology is that they feed at high latitudes in the poles, breed in the tropics, and they have this migration that's driven between the two needs,” says lead author Jane McPhee-Frew, a marine guide and biologist at the University of New South Wales, to the Australian Broadcasting Corporation’s Ellen Phiddian.
But, for the new study, scientists found more than 200 records of calves spotted south of these cut-offs. Some were seen as far south as Tasmania and New Zealand, at around 43 degrees latitude, which is between 807 and 932 miles farther south than expected.
And that’s just where the sightings stopped—it’s possible humpbacks are giving birth even farther south.
“Eventually, we just ran out of land to see them from, so we don’t actually know where the limit is,” McPhee-Frew says in a statement from the university.
The scientists gathered the baby humpback whale sightings from a variety of sources, including migration surveys, stranding reports and citizen science observations from tourism boats. In total, the data included 209 observations consisting of 11 births, 41 strandings and 168 live calves; the scientists believe the reports represent at least 169 individual calves.
Though the stranding data went back as far as 1991, most of the opportunistic observations occurred more recently, from 2016 forward. Roughly two-thirds of the total opportunistic observations occurred in 2023 and 2024.
Since this is the first study of its kind, the scientists aren’t sure whether this is a new trend or just something no one had noticed before.
“It may be the case that this has always been happening and we’ve just not documented it well or been paying attention,” study co-author Vanessa Pirotta, a wildlife scientist at Macquarie University, tells the Guardian’s Petra Stock. “Or it may be something new is happening because waters are becoming warmer further south of those traditional tropical areas, which means that they’re more favorable for a humpback whale to have a calf.”
The findings were not necessarily a surprise, either, because humpbacks are known to feed, mate and give birth along their migratory corridor, says Olaf Meynecke, a marine scientist at Griffith University who was not involved with the study, to the Australian Broadcasting Corporation.
However, scientists “don't know to what extent they are doing this,” he adds.
The findings also raise additional questions. The biggest one? If humpbacks don’t need to be in tropical waters to give birth, then why are they migrating to do it?
“I don't know, but it's exciting,” McPhee-Frew tells the Australian Broadcasting Corporation.
One possibility is that whales born in warmer waters have better chances of survival. These regions have fewer predators, like orcas, and the waters tend to be calmer. The warmer climate may also be beneficial for baby whales—called neonates—with poor temperature regulation.
In addition, calves born farther south must still migrate northward with their mothers. This long journey is not only taxing, but it also takes them through busy shipping lanes and past urbanized areas, which opens them up to risks like boat strikes, entanglement and pollution.
“Newborns are like Great Dane puppies,” says study co-author Tracey Rogers, also a biologist at the University of New South Wales, in the statement. “They have those long, enormous fins that they need to grow into, and they’re not very strong swimmers. So they rest a lot of the time on their mum’s back.... It’s heartbreaking to think of these young whales traveling through busy ports and dangerous shipping lanes with those long, clumsy fins.”
Moving forward, researchers might be able to answer some of these questions by following calves born in cold waters and comparing their health and longevity to those born in warm waters. Scientists are also curious about other effects, like whether calves born in colder waters also return to these same areas when they’re ready to reproduce.
In the meantime, the scientists say their findings could have important conservation implications. For instance, with calves being born farther south than previously thought, policymakers may want to consider expanding marine protected areas or launching awareness-raising campaigns to help keep them safe.
“We can't be in a situation where we're putting any age of whales—especially baby whales—in a situation where they're getting caught in nets, being exposed to chemicals, being hit by boats and being harassed,” McPhee-Frew says in the statement.
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Humpback Whales Give Birth Much Farther South Than Previously Thought, Study Finds
Humpback Whales Give Birth Much Farther South Than Previously Thought, Study Finds
Researchers in Australia found records of humpback whale calves more than 900 miles farther south than expected
A mother and baby whale spotted swimming near Kiama, New South Wales, Australia.
Vanessa Risku / Instagram: droning_my_sorrows
Each year, humpback whales migrate predictably between cold, nutrient-rich feeding grounds and warm, tropical calving grounds, where they give birth and care for their young.
Or so scientists thought. Researchers in Australia recorded calves being born much farther south than previously thought, which challenges long-held assumptions about humpback migration patterns. They shared their findings in a new paper published yesterday in the journal Frontiers in Marine Science.
Humpback whaleslive in all of the world’s oceans. These behemoth marine mammals are highly migratory, swimming thousands of miles each year. The longest humpback whale migration ever recorded was 8,106 miles, from South America to Africa, though more typical distances are around 5,000 miles.
In the Southern Hemisphere, humpbacks head to the krill-rich waters of the Southern Ocean around Antarctica every summer, then venture up the eastern and western coasts of Australia toward the warmer waters north of the continent every winter.
Researchers long believed that humpbacks only gave birth to their calves in the tropical waters north of 28 degrees latitude on Australia’s east side and north of 23 degrees latitude on the west side.
“Our general concept of humpback whale ecology is that they feed at high latitudes in the poles, breed in the tropics, and they have this migration that's driven between the two needs,” says lead author Jane McPhee-Frew, a marine guide and biologist at the University of New South Wales, to the Australian Broadcasting Corporation’s Ellen Phiddian.
But, for the new study, scientists found more than 200 records of calves spotted south of these cut-offs. Some were seen as far south as Tasmania and New Zealand, at around 43 degrees latitude, which is between 807 and 932 miles farther south than expected.
And that’s just where the sightings stopped—it’s possible humpbacks are giving birth even farther south.
“Eventually, we just ran out of land to see them from, so we don’t actually know where the limit is,” McPhee-Frew says in a statement from the university.
The scientists gathered the baby humpback whale sightings from a variety of sources, including migration surveys, stranding reports and citizen science observations from tourism boats. In total, the data included 209 observations consisting of 11 births, 41 strandings and 168 live calves; the scientists believe the reports represent at least 169 individual calves.
Though the stranding data went back as far as 1991, most of the opportunistic observations occurred more recently, from 2016 forward. Roughly two-thirds of the total opportunistic observations occurred in 2023 and 2024.
Since this is the first study of its kind, the scientists aren’t sure whether this is a new trend or just something no one had noticed before.
“It may be the case that this has always been happening and we’ve just not documented it well or been paying attention,” study co-author Vanessa Pirotta, a wildlife scientist at Macquarie University, tells the Guardian’s Petra Stock. “Or it may be something new is happening because waters are becoming warmer further south of those traditional tropical areas, which means that they’re more favorable for a humpback whale to have a calf.”
The findings were not necessarily a surprise, either, because humpbacks are known to feed, mate and give birth along their migratory corridor, says Olaf Meynecke, a marine scientist at Griffith University who was not involved with the study, to the Australian Broadcasting Corporation.
However, scientists “don't know to what extent they are doing this,” he adds.
The findings also raise additional questions. The biggest one? If humpbacks don’t need to be in tropical waters to give birth, then why are they migrating to do it?
“I don't know, but it's exciting,” McPhee-Frew tells the Australian Broadcasting Corporation.
One possibility is that whales born in warmer waters have better chances of survival. These regions have fewer predators, like orcas, and the waters tend to be calmer. The warmer climate may also be beneficial for baby whales—called neonates—with poor temperature regulation.
In addition, calves born farther south must still migrate northward with their mothers. This long journey is not only taxing, but it also takes them through busy shipping lanes and past urbanized areas, which opens them up to risks like boat strikes, entanglement and pollution.
“Newborns are like Great Dane puppies,” says study co-author Tracey Rogers, also a biologist at the University of New South Wales, in the statement. “They have those long, enormous fins that they need to grow into, and they’re not very strong swimmers. So they rest a lot of the time on their mum’s back.... It’s heartbreaking to think of these young whales traveling through busy ports and dangerous shipping lanes with those long, clumsy fins.”
Moving forward, researchers might be able to answer some of these questions by following calves born in cold waters and comparing their health and longevity to those born in warm waters. Scientists are also curious about other effects, like whether calves born in colder waters also return to these same areas when they’re ready to reproduce.
In the meantime, the scientists say their findings could have important conservation implications. For instance, with calves being born farther south than previously thought, policymakers may want to consider expanding marine protected areas or launching awareness-raising campaigns to help keep them safe.
“We can't be in a situation where we're putting any age of whales—especially baby whales—in a situation where they're getting caught in nets, being exposed to chemicals, being hit by boats and being harassed,” McPhee-Frew says in the statement.
Get the latest stories in your inbox every weekday.
#humpback #whales #give #birth #much
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