Animal migrations are extraordinary events. From butterflies to bats, wildebeest to whales, many creatures are urged by instinct to move. And move they do, often hundreds or even thousands of miles in a single journey. Motivations vary: some are drawn towards food, others sex; many seek to avoid the brutal vagaries of a northern winter. For all, there are surely additional factors beyond our human understanding. While scientists may disagree on exactly why
humpbacks migrate, there is little disagreement that the journey from the North Atlantic to the Silver Bank (and surrounds) is an arduous one for them. Fat stores accumulated during the short but bountiful northern summers are rapidly depleted as adult whales rarely have opportunity (or inclination?) to feed on the calving grounds; the females fast even while producing enormous quantities of nutrient-rich milk for their rapidly growing newborns. Other physical threats are of human origin and more insidious: ship propellor strikes are not uncommon, and encounters with fishing line or other industrial implements are practically endemic (it is estimated that up to 70% of humpbacks bear scars from entanglement). Juveniles are particularly vulnerable, with whales in their naive second year of life facing the highest mortality rates from human-created threats.
This whale was found entangled on the Silver Bank in February 2012. To read more about the disentanglement, click here. © Tom Conlin
The threats do not diminish on the return journey north. Indeed, mothers with young calves face additional risk from orcas, those supreme predators of the sea. Babies in their first year of life present the greatest target; those that survive predation attempts by orcas will often carry physical scars into adulthood. Psychological scars are sometimes also born, a fact unsurprising in animals of such emotional complexity. Indeed, traumatized yearlings will occasionally stay with their mothers for extended periods, returning south by her side and retaining many of the behavioral aspects of infancy. Among our early encounters on the Silver Bank this week is with just such a mother and calf pair. While it is not clear whether the mother encourages or the calf initiates this sort of arrested development, the evidence for it is clear: this heavily scarred calf sticks close to mom, even tucking himself beneath her protective pectoral fins and accepting the occasional nose push. Despite their unusual situation, the pair are not at all reluctant to share their space with the innocuous humans. We are able to slip into the water with them for 20-25 minutes at a time, with the escort circling thrillingly close.
Yearling that was still with mother, perhaps due to trauma during 1st year.
The week brings other thrills as well: highlights include a second mother and calf pair (with patient escort) displaying some impressive surface antics within feet of the tender. Baby breaches at least 30 times, sometimes close enough to feel the spray. And then the trio are joined by an aggressive challenger, who lob tails over and over just off our bow, impressing us with his tremendous power. The female is less impressed than we are though: she leaves eventually with her original escort, his patience having paid off. A third mother and calf encounter includes a reversal of the commonly seen situation: this pair circles repetitively and eagerly around a singing male, his plaintive song clearly intriguing to mom (this escort is less tolerant of baby, even displaying a few semi-aggressive tail slashes). A series of high-pitched squeaks and moans and whoops in this situation indicate verbal communication between the potential mates, the nuances of which we can only guess at. And finally, an encounter with another mother and calf pair reinforces just how effective the soft-in-water approach is at gaining the trust of whales initially reluctant to interact: mom allows for increasingly long interactions, and displays increasing comfort with our approach.
© Jean-Francois Chabot
First time mom “Bounce” with calf. © Joanne Jarzobski
Remarkably, in a week filled with dramatic and touching encounters, the best was saved for last. Our last morning on the Silver Bank was dominated by dancers, pairs of whales in coordinated courtship. One encounter was particularly outstanding: far from being concerned about us witnessing their intimacy, the dancers seem to want to incorporate us in the moment, circling around the tender and even the swimmers repetitively. We are left awed and exhilarated by the proximity of the pair, and impressed with how self-aware these enigmatic animals are; each whale making subtle and continual adjustments to their position to avoid colliding with the swimmers around them.
“Samara” dancing around the swimmers. © Joanne Jarzobski
So all in all, a fantastic and unique week, above and below water. And aboard the Explorer as well: with a special guest, Joanne Jarzobski of Hyannisport Whale Watchers, who shares her 17 years of experience and considerable knowledge about humpback whale behavior on their northern feeding grounds. Joanne also helps to maintain a considerable database of whale identification photos, and was able to recognize several whale “friends” here on the Silver Bank (see photo below), helping us fill in the blanks on their year-round stories. Aquatic Adventures looks forward to further communications with Joanne, and encourages guests to assist ongoing research on humpbacks (Joanne’s and that of other groups) by sharing their own fluke and dorsal fin photographs.
© Joanne Jarzobski
Until next week…