February 28 ~ March 7, 2015
Within every group of organisms, from the tiniest to the largest, there is variation. In our own species, we find variation is obvious: we quickly discern blue eyes from brown, or an outgoing personality from a more shy one (though other variation, such as susceptibility to disease, is less obvious, even in those closest to us). Although we are less adept at recognizing variation in other species, subtle or otherwise, it is there. Humpbacks have visible variation in color patterning, shape, size, and behavior, among other things. A week on the Silver Bank provides a great deal of intimate interaction with these fascinating creatures, making it clear that each is as unique in appearance and personality as we are.
Variation in behavior was also evident this week: in contrast to Sockeye’s defensiveness, other female and escort pairs (and female, calf and escort trios) were happy to relax with us. Escorts sometimes get a reputation for acting possessive, but many are just as interested in us as the females they accompany. In one such encounter, a pair even begins “dancing” with us for a few moments, rolling, turning, and winding around us and each other. They glide away, then circle back, spyhopping just next to us. In a second encounter, a mom brings her tiny calf in for a close look, circling us several times before eventually heading off.
A last encounter is also special: a stationary singer. In contrast to several “one-man traveling band” singers we’ve encountered this season, this eager male allows us to position ourselves directly above him for 10-15 minutes at a time. The unique patterns of this year’s song are clearly evident, with a “three squeaks and one moan” phrase apparently quite popular (while humpbacks may sing continuously for more than 24 hours, the basic song consists of patterns that repeat every 8-12 minutes or so). Cetaceans have no vocal cords, so whales generate their songs by forcing air through their massive nasal cavities, and the force of these reverberations are felt in our chests. It’s an impressive performance as part of another great (and varied!) week on the Silver Bank.