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OF PILOT WHALES EXTRAORDINARY FATE
OF PILOT WHALES EXTRAORDINARY FATE
Text and photos JAKUB BANASIAK
Young pilot whale is approaching the boat
Of the listed diving destinations, pilot whales are most often found in the Galapagos. They swim in large pods in the nutrient-rich waters of the Humboldt Current. In the open sea, they often accompany bottlenose and common dolphins. They travel between islands in search of squids, small fish, and octopuses. They prefer deep waters and are often found in large pods of up to several dozen members. They can be easily approached by boat, and if we turn off the zodiac's engine, curious individuals will often swim up to us on their own.
They can sometimes be confused with other marine cetaceans of the blackfish family – pigmy killer whales, although they differ in head shape and body slenderness.
Pigmy killer whale in the Galapagos
Pilot whales can be recognized by their distinctive bulbous heads and prominent, rounded dorsal fins located more anteriorly. They are sleek and slender when young, and gain weight and girth as they age. A fully grown pilot whale can weigh up to four tons and measure up to 6.5 meters in length.
As with all other dolphins, special care should be taken when encountering pods with younglings, so as not to interfere with calf care, feeding, schooling, and to avoid stressing the mothers and other family members involved in caring for them.
In short-finned pilot whales, calves are born after a gestation of nearly 15 months. Their weight and length measurements are about 55 kg and 1.4 m. Although weaning occurs after about two years, females can continue to feed the young for a period of years to come. This shows a complex social structure in which older females can give their own or related calves a "reproductive advantage" precisely through extended feeding. Females give birth to an average of four to five calves. Mating takes place throughout the year. For example, in the waters between Tenerife and Gomera, newborn pilot whales can be encountered basically every month.
Adult pilot whale dives under boat
Do not get too close
Interestingly, young pilot whales, at least in this part of the Atlantic, do not swim exclusively beside their mother – they also take turns swimming beside other adults – both females and males.
Pilot whales often gather into larger groups that stay together for up to several weeks, allowing them to travel, feed, rest and socialize together.
Female with her young
Researchers observing a population of more than 3,000 pilot whales that spend summers off the coast of Cape Breton Island in Nova Scotia, Canada, observed 356 identifiable calves during more than 600 encounters with the animals over a three-year period. Roughly a quarter of them was observed occasionally sticking close to an adult individual that was not their mother. One baby took turns swimming next to an average of five adult companions. It is believed that the calves can thus learn social behaviour from their experiences with different pod members.
Family group
When one or more members of the pod dives in search of food, we can observe calves and young on the surface left in the care of an adult. These groups are the so-called "nursery groups". If we just turn off the engine of our boat and wait patiently, it may happen that curious little ones come very close to us. They often then show one or both pectoral fins, lift their heads out of the water to look around (known as spyhopping), or bump their fins against the surface to attract attention.
The calf in the foreground demonstrates the pectoral fin
However, the most interesting things happen at the interface with other cetacean species.
On May 17, 2021, a research team from Far Out Ocean in New Zealand reported that they had observed a female bottlenose dolphin interacting with a pilot whale calf as if the newborn was her own offspring. Scientists believed that the dolphin had adopted the young whale over a month earlier and had been caring for the calf the entire time.
Far Out Ocean has confirmed that this is not the first time a bottlenose dolphin has been observed caring for the young of another ocean mammal. It is unclear why this species seems to be comfortable with the role of surrogate parent. Perhaps it is giving off a strong maternal instinct after losing its own offspring.
Cetacean surfacing behaviour – spyhopping
Such mixing between species is not uncommon off the coast of New Zealand, so it is possible that a pilot whale calf later met its pod and was reunited with its biological parents or other individuals of its species. Such adoptions usually don't last more than a few months – and given that the size of even young pilot whales is much larger than that of a dolphin calf, the pilot whale's baby needed more milk than a bottlenose mother can provide.
Bottlenose dolphins often share the same body of water with pilot whales
Perhaps it was an awkward accidental "kidnapping". Scientists believe that pilot whales and bottlenose dolphins get along well, and the Far Out Ocean team has never yet observed any interspecies aggression between the two groups which are together in 50 percent of pilot whale sightings in the area.
A similar event also occurred in the Strait of Gibraltar. However, the adopted calves here usually belong to species that are the same size or smaller than bottlenose dolphins, such as common dolphins. The case of the adoption of a pilot whale calf is something new in the area.
In August 2021 observers from Orca Guardians Iceland spotted a newborn pilot whale calf (still with fetal folds visible on its skin) swimming in an echelon formation with a female orca that was well known to local researchers in western Iceland. Other orcas were seen nearby, but no other pilot whales were observed.
In June 2022, scientists from the Icelandic Orcas project had very similar observations in southern Iceland. Again, a pilot whale calf appeared among the orcas, even though no pilot whale pod was observed nearby.
This is surprising, as pilot whales and orcas have already been found to behave antagonistically to each other on several occasions in all these areas, with pilot whales actively chasing off pods of orcas, pursuing them at high speed until the orcas left the area.
The cub bravely follows the adult female
For the most part, when both species were observed simultaneously in the waters around Iceland, the orcas generally exhibited avoidance behaviour by keeping their distance from the pilot whales and quickly moving away when they began to approach. Yet this did not prevent the orcas from taking care of the pilot whale calf.
Alloparenting, or surrogate parental care of young individuals that are not the direct offspring of the caregiver or caregivers, including young representatives of other species, is an extremely interesting phenomenon. It probably has to do with the highly developed brains of these animals. Perhaps the so-called spindle neurons play an important role here. In the mammalian brain, spindle neurons are part of the limbic system, which is involved in processing and regulating emotions. Spindle neurons were previously thought to be found only in humans and great apes. However, cetaceans also have a large number of these neuronal structures, making them highly empathic, emotionally intelligent, and capable of forming complex social structures.
Could orcas have adopted a pilot whale calf that had separated from its own pod? Despite the very complex and seemingly unfriendly relationship between the two species, perhaps the family's strong sense of social structure and high level of empathy gave this calf a second chance.
The calf usually stays fairly close to the caregiver
The world of dolphins still holds many mysteries. At the same time, it proves us every year that humans are not the only ones who are unique, empathetic, and extremely emotionally intelligent.
