Nature, red in tooth and claw
Alfred Lord Tennyson
On land, we have a very good understanding of how the most intelligent nonhuman animals live. By contrast, our understanding of the same in the sea is very poor. Nature documentaries exacerbate the problem by mixing high picture quality with definitive sounding statements that have minimal foundation.
As an example of this, take a case I previously covered on these pages: humpback whale songs. These are very efficient at repelling females from their male singers, so they’re not love songs. That continual erroneous attribution masks a far more complex situation than any terrestrial equivalent.
This singing attracts males to other males. Once they approach each other, something that looks very like a courtship dance begins. Given that they sing mostly on mating grounds, it should come as no surprise that this ritual movement occasionally ends in a fight. It might seem reasonable, then, to assume the next simplest explanation and think of their tunes as challenge songs, but we have reason to doubt even that is correct. For starters, though females frequently approach bulls after their male-male dances, no instance of mating has ever been observed following those post-dance male-female meetings! Another clue is that, we frequently observe two male humpbacks working in pairs. What is particularly hard to explain is that they often coordinate in very dangerous tasks with no benefit to themselves, or even their own species. This manifests as saving other mammals from the depredations of killer whales.
Recently a systematic study of these unusual protective behaviours was published, and it showed the importance of these pairings. Additionally, we should note that younger males group in pairs when they try to displace a more mature male from escort duties. Escort duties themselves, are yet another behaviour of humpbacks that has resisted attempts at explanation in terms of instinct driven by evolutionary pressures, so I will briefly examine whale escorting in turn…
After mating season, the male humpback seem to pay little attention to the females. Eleven months later the mother gives birth, after which a large male sometimes appears by their side, following them, and protecting them from danger. Fatherhood of that calf is not linked to escort duties (some researchers claim it is never the father), but even if it was, evolutionary pressure would give advantage to those who didn’t escort and looked for a new partnership instead – doubling his chances of having children. So why are males paying such attention to females who won’t be ready to mate until at least the following season? The easiest way to solve it is to think of acts that pay off years later in terms of future breeding opportunities. This presents a massive problem since no nonhuman land animal plans this long-term. It would also entail the need for elaborate anti-cheating strategies. Now… let us return to those male pairings…
The seemingly altruistic protective activity of male pairs begs the question of how and where they forge such close bonds. The plainest solution is that they could be very closely related (as in brothers), but I have heard this isn’t the case. I can’t help noting, if a male never gets the chance to mate, these male-male partnerships would be the most important relationships of their adult life. Given that, I wonder if those male-male dances may represent more than a simple challenge to dominance?
I have also previously mentioned the anecdotal evidence that resident killer whales attack and chase meat eating transient killer whales wherever they find them. Bolstering this is much peer reviewed evidence that transients spent a lot of time and energy avoiding residents but not visa versa. They are the same species and their diets are mutually exclusive, so there is no food competition. I hate to anthropomorphise but, once more, we have evidence of a systematic effort that takes a form that one might expect in a moral crusade.
One clue as to the resident mind comes from a scientist that had become well know to a pod of killer whales that she studied each season off British Colombia. She described how a resident mother whale, whose son had been non-fatally shot by some ‘sportsman’, pushed him toward the research vessel, rotating his injury to the surface, all the while eyeing those on board. If we allow the possibility that killer whales have very high intelligence we might have been tempted to believe that she expected those researchers to protect her pod from other renegade humans.
Finally we get to the case of sperm whales. In the North Atlantic, male sperm whales are occasionally seen swimming freely with killer whales, yet when played the calls of transients (which live only in the North Pacific), they immediately surfaced and congregated. Such behaviour is hard to explain for several reasons. Firstly these large whales are observed to be solitary in all other circumstances. Secondly killer whales have never been observed attacking male sperm whales, but male sperm whales have been observed to harass killer whales.
To summarise, there are many lines of evidence indicating a massive and continuing struggle boiling under the ocean surface between mammal eating killer whales and at least three fish and krill eating whale species (including their own). We, as yet, are totally unable to explain its nature in terms of conventional ethology.