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Dolphin Watch
BB, the bulls and bulligerance
By ANN WEAVER
Article published on Thursday, July 17, 2008
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![[Image]](/content_images/071708_out-01.jpg) |
| Photo by ANN WEAVER |
| BB is a most memorable bull because of the distinctive double notches of his dorsal fin. Whoever bit him bit hard enough to severe the fin’s tough fibers. |
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Have you ever felt that your fate depended on someone else? What do you think about that? Don’t you envy the wild animals, whose fate lies in their own strength, cleverness and wit?
It was late May. The water was up to 79 degrees F., not hot enough to make the dolphins lethargic. Yet a big bottlenose dolphin bull hunted the south side of a small bay diffidently.
Like hunting dolphins, he submerged for long periods and emerged far from his vanishing point. Unlike hunting dolphins, he surfaced sluggishly. He often rested at the surface.
His body was covered with toothrakes. He’d been fighting.
The lone bull was BB. How strange for him to be alone.
BB is a most memorable bull. Seeing him is remembering him, because of the distinctive double notches of his dorsal fin. Whoever bit him bit hard enough to severe the fin’s tough fibers.
BB is big. He reminds me of a strapping young lumberjack in the midst of establishing his social status among other males. Would you believe his ultimate fate could depend on another dolphin?
Though strange to see BB alone, it’s strange to see any dolphins alone. In 2007, we found a single dolphin on just 5 percent of 120 surveys. In 2008, we’ve found a single dolphin on just 3 percent of the 60 surveys so far.
BB was never one of them. Nor were any members of BB’s so-called cadre, the group of males I see with him the most. There are five cadre bulls: BB, DD2, N, Rippington and Riptab. BB’s social life revolves around them. By revolve, I mean he was with at least one of them 93 percent of the times we’ve seen him from January 2007 to June 2008 (180 surveys).
So, was his sluggish sojourn related to local bull politics? I checked BB’s last 18 months of data for tell-tale action in the bottlenose bullpen.
I was thinking about that bottlenose singularity called bonded bulls. Bonded bulls are pairs of mature bottlenose bulls who show consistent companionability with each other. Pairs operate as a nearly inexorable dynamic duo for the last several decades of their long lives.
Unlike Batman and Robin, bonded bulls share a more equitable status, trading off front line operations as a well-coordinated team (though admittedly sometimes competing against each other). In their collective strength, bonded bulls can be pugnacious. Pugnacity comes from strength in numbers.
The scientific literature says little about how bonded bulls establish their team spirit. It seems to me there should be something like preliminary trials where males test potential candidates and eventually choose one, roaming together thereafter.
Not all bulls bond. BB is not bonded. From the activities of the last 18 months, I’d say he’s in negotiation.
I’ve often wondered what really goes on between BB, DD2 and N. (The brass ring and Dawn of knowledge). So I started by seeing if BB has a favorite among the cadre of likely candidates. I generated the degree of association for each pair of cadre bulls, the number of times two bulls are seen together divided by their times with other dolphins.
If two dolphins were always together with no one else, their degree of association number would be 1.00. As per America’s foremost field biologist, George Schaller, an association of 0.40 or higher reflects animal companions.
Surprisingly, these bullish associations aren’t relative to each bull’s frequency in the study area. BB, DD2 and N are residents. We see them regularly (40 percent, 41 percent and 33 percent of surveys, respectively). On the other hand, we see Rippington and Riptab rarely (14 percent and 17 percent, respectively).
Despite these disproportionate opportunities to socialize, BB’s degree of association with all of them is high. In order, BB is most companionable with DD2 (.48), Riptab (.35), Rippington (.27) and N (.24).
So while Riptab and Rippington swim here rarely, they swim with BB when here. Pilot study pictures show this threesome together as smaller and younger dolphins. They may have grown up together.
Unlike their pals, DD2 and N rarely swim with these latter bulls. DD2 is companionable with N (.37), intermittent with Rippington (.18) and rarely with Riptab (.10). The same goes for N (Rippington .16, Riptab .07).
The data show that DD2 and N hang out, DD2 and BB hang out but N mainly hangs out with BB when DD2 is there (81 percent of the time!).
It would appear that DD2 can’t decide between BB and N, and BB has alternatives. All this causes some level of conflict … until bonded bulls show up. Cadre competition stops. Cooperation starts.
Last March, for example, a major convergence of dolphins culminated in a major fight between resident males and transient males apparently over available females like P, DD1 and Stick. Together, the cadre took on belligerent transients Edge and KK, something they never do in smaller groups.
Once the bonded bulls were not around, the cadre roamed in loose pairs without tensions through April. Interestingly, when tensions arose again, they arose between the bulls with the least social connection, N and Riptab. When one fight between them got nasty, DD2 gave up and left. BB never got involved.
Belligerent bulls Edge and KK returned last June. In the brass ring, I related how Riptab hurried away and N and Midface wouldn’t take on the belligerent until DD2 and BB swam into the area. The combined cadre successfully rousted the belligerents.
That October, the cadre was fighting amongst itself again. Curiously, in the aftermath of conflict, BB often swims with Rippington far from the previous action.
It was strange to see it all begin to play itself out again this spring. Another major spring assembly. Another major conflict. Another sluggish swim by BB and Rippington, covered with toothrakes.
BB even had a head bruise. N was covered with toothrakes and actually left the area for over a month. BB and DD2 were swimming together again until the day I found BB alone in May. Since then, we’ve seen him with everyone but the cadre.
It must mean another round of negotiations.
The cadre’s companionable competition continues. BB’s future is anybody’s guess. My guess is that DD2 can’t decide who to support, BB or N. I have that problem myself!
Dr. Weaver studies wild dolphins under federal permit GA1088-1815, National Oceanic and Atmospheric Administration. Send her an e-mail at aweaver@argosy.edu or visit www.dazzlingdolphins.com.
Revision note: Updated version posted July 21, 2008.
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Article published on Thursday, July 17, 2008
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