A pack of killer whales cut through the Salish Sea, on the hunt for salmon. In the lead was Granny, the charismatic matriarch of J-pod: a group of Southern Resident killer whales who patrol the waters off the Pacific Northwest coast of British Columbia and Washington. Sometimes referred to as “the Energizer Bunny,” Granny was a tireless leader who chose her pod’s travel route, sought out Chinook salmon, and kept her family close, often summoning stragglers with a slap of her tail.
Hot flashes and night sweats are a luxury in the wild where animals rarely live beyond their reproductive years.
Granny was literally a grandmother. She likely went through menopause around 45 years of age and then she lived another 60 years, reaching an estimated 105 years old. Male killer whales typically expire around 29 years old, but even if they live longer, they don’t surpass their reproductive years. Menopause is very rare in nature, well-documented in only a few species like humans and short-finned pilot whales. Hot flashes and night sweats are a luxury in the wild where animals live just long enough to reproduce. On the Pacific Northwest, salmon are the most visible example of this, washing up dead and bloated on riverbanks shortly after they spawn. So, why did Granny reach such an esteemed age?
It turns out killer whale retirement isn’t all that leisurely. Granny played a key role in J-pod’s survival, helping her daughters raise their young while passing along decades of ecological wisdom. But older female elephants also provide for their social groups while continuing to reproduce and pass on genes. So, what makes killer whales different?
Granny outlived all her children, but she continued to care for the rest of the pod.
In a 2016 paper, University of Exeter behavioral ecologist Darren Croft proposed an explanation for menopause that focused on reproductive conflict between the generations. A grandmother’s calf is 1.7 times more likely to die than her daughter’s, if both give birth at the same time. A grandmother struggles to shore up the energy to survive the physical demands of raising a calf; she needs 42% more food! This is especially difficult for grandmothers who are busy helping other pod members.
This leads to another explanation for menopause, one favoured by marine mammal biologists like Lance Barrett-Lennard who heads Ocean Wise’s Marine Mammal Research Program. In species like humans — and killer whales — the young rely on their mothers for care and learning for many years. As a female ages and her odds of dying increase, her offspring have less and less chance of reaching an age where they can survive without her. At some point, a female will leave more living descendants by putting her remaining energy into caring for her existing offspring rather than by producing more. According to this view, menopause is a trait that evolved to maximize females’ lifetime production of viable offspring.
Male killer whales require a lot of help from their mothers, particularly among Granny’s Southern Residents. When researchers first began to study Granny and J-pod in the 1970s, she was almost always seen with an adult male named Ruffles, thought to be her son. By supporting Ruffles throughout his life, Granny ensured that he could reproduce and further her line without the extra work of caring for more mischievous youngsters of her own. Granny outlived all her children, but she continued to care for the rest of the pod. After Ruffles’ passed, she extended her motherly instinct to the other young males in her pod. Unlike killer whales, elephants don’t go through menopause because male elephants leave their mother’s group – they simply aren’t around for their mothers to help.
Sadly, Granny passed away in 2016, leaving scientists uncertain about the fate of J-pod. However, two remaining females, Slick and Princess Angeline, have probably reached menopause already and could take on Granny’s role as post-menopausal provider. How they step into these leadership roles will determine J-pod’s survival in the coming years.
In the mid-1980s, Kathy Heise found herself tending a lighthouse overlooking a foggy channel in the Pacific Northwest. It became the perfect place to learn about killer whales, calling and echolocating along the Inside Passage of Vancouver Island, British Columbia. These were the early days of echolocation research. Heise and her husband — both budding marine biologists — were hoping to answer blue-sky questions about echolocation. How do killer whales use echolocation? Does turbid water affect it? And how does echolocation differ between whale populations?
After they arrived, she and her husband attached an underwater microphone (called a “hydrophone”) to the shore of Chatham Point in Johnstone Strait, 18 metres beneath the water line. Then, they started eavesdropping round the clock on the clicks and chirps of passing whales and dolphins.
When some whale chatter came over the line, they hustled out of the house and down to the shore. If the weather was good — often a crapshoot in the Pacific Northwest — she climbed into a skiff and motored out to the action. The first priority was to photo-ID the whales and confirm which social group they belonged to. (The British Columbian coastline is home to two fish-eating resident whale groups and a third group of marine-mammal eating Bigg’s whales, formerly known as transients.)
“Echolocation is very directional,” Heise explains. “If the animal is facing you, you’ll hear it. If the animal is facing away, depending on the angle, you don’t hear it. That’s how you can tell if the whales are coming toward you.” She carried with her a World-War-2 navy hydrophone, mounted on a pole, which she turned in all directions, scanning the ocean for calls.
The transient whales, she observed, listened silently for their prey to make a noise. The hydrophone would be quiet, but from the boat she could often see prey (typically porpoises or seals) floating silently at the surface, keeping their splashing to a minimum. Sometimes they would hide up against the research boat. When the whales made a kill, the ocean would suddenly explode with the eerie sounds of transient whale vocalizations.
At the time, these were entirely new and novel observations; no researcher had documented a transient whale-kill before. At Chatham Point, Heise also witnessed the arrival of Pacific white-sided dolphins on the coastline. These dolphins used to live farther out at sea and researchers knew very little about them. When they moved inshore, it gave researchers like Heise the opportunity to study them up-close and in the wild.
However, Heise was up against the technical limitations of the time. Her World War 2 hydrophone, for instance, could record up to 25 kilohertz. (The human ear hears sound frequencies up to 20 kilohertz.) We know now that whale echolocation extends to over 100 kilohertz, particularly when they zero in on prey.
Thirty years later, the technology has advanced hugely and Kathy Heise’s work on echolocation continues apace. In a recent study, she attached suction-cup eye-coverings to Pacific white-sided dolphins and observed how they used echolocation in a controlled habitat. The dolphin’s echolocation ability is impressive, but they don’t always use it reliably. According to the World Wildlife Federation, 300,000 dolphins, whales and porpoises entangle themselves in fishing nets and drown each year. Knowing more about how they become entangled could lead to improved fishing gear and save lives.
In the coming years, Kathy Heise’s work on echolocation will continue to expand in new directions. She advises non-profits, the shipping industry and local ports on guidelines that reduce underwater noise. Chatham Point is still a special place for her, where she had her first encounters with echolocation and saw how instrumental it was in the lives of whales and porpoises. Now she’s putting that knowledge to work, keeping the peace for underwater animals.