Dolphin Watch
Tax time
By ANN WEAVER
| Article published on Thursday, Nov. 16, 2006 |
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![[Image]](/content_images/111606_out-01.jpg) |
| Photo by ANN WEAVER |
| VC shoots into the air, twisting wildly in a dazzling display of dexterity in what is most likely an attempt to escape the remoras attached to its body. |
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In Margaret Mitchell's "Gone With the Wind," heroine Scarlett O'Hara claimed famously that it was never the right time for death, childbirth, or taxes.
Taxes at least seem exclusively human. Yet life beyond humanity isn't simple either. To my eye, at least two tax collectors skim the surface of aquatic revenues, sea gulls and remoras. Draw your own parallels.
Sea gulls and brown pelicans abound here. Sea gulls are phenomenally noisy birds particularly aroused by food. The more food, the more strident their cries.
Calls attract more gulls (conspecifics) who, as if materializing out of the ethers, rush in to plunder. It's like scrounging up lunch during The Depression and then screaming in excitement. Naturally, you end up 'sharing' the meal.
Since food cries alert competitive conspecifics, you have to wonder how the gulls benefit from the contests they create. Maybe they reciprocate: Compete with me today, I with you tomorrow. Ultimately, we all eat. On the other hand, maybe silent gulls are more successful.
Though habitual advertisers, gulls are nonetheless capable ecological generalists, earning their living in many different ways. Some specialize on brown pelicans as small cap sources of gull revenue.
Brown pelicans are unique among the seven species of pelicans for plunging on their food from the sky. They fish with the expandable pouch of the lower jaw, engulfing prey in sudden gallons of confusing water.
The water weighs more than the pelican. So pelicans surface and bow their heads as does a person in prayer. The bowing drains the water but retains the fish. When head-bows are followed by upward jerks of the beak, the bird is swallowing. The jerk says fishing was successful.
Local gulls capitalize on pelican head-bowing as do creative tax collectors. They circle until hunting pelicans have a piscean paycheck in hand and land on their bowed heads. The gesture may function to disrupt swallowing or capitalize on scraps. It must be annoying. Some pelicans shoo the gull away with a jerking gesture in their direction. Others twist out from under it or escape with a flap of wings. Many do not react overtly, long-sufferingly completing the tasks at hand.
Remoras secure another nautical tariff with a different abrasive touch. They are fish whose dorsal fins, the one of the back, are modified for suction. They attach to large hairless marine animals and live on sloughed skin and food debris.
For all their parasitism (benefits to their hosts are unclear), they don't necessarily attach permanently. Good swimmers on their own, some float along the host's skin, tickling a fin one minute and the belly the next. On a person, the sensation is like an emery board drawn mildly across your skin. Humans can of course easily brush off such annoyances with a sweep of the hand. Dolphins can't.
An October quintet of bottlenose dolphins socialized slowly across a sea grass meadow. Probable bulls KK and Edge mingled with mothers Tanks and Valiant. Valiant's year-old calf VC wove among them. They entered a labyrinth of narrow channels and began foraging for breakfast. Rather, the adults foraged. VC messed around.
The behavior is typical for dolphin groups with 'toddler' calves. Too young to hunt in earnest, youngsters explore in an invisible circle around mom. The circle's size varies with calves' age (and maternal tolerance). The older the calf, the bigger the circle around mom.
The pattern was familiar. VC's behavior was not. I've rarely seen such ardent aerial antics. Over a dozen times, VC shot into the skies and twisted wildly like a radio-controlled champagne cork. The repetition was not odd. The dazzling display of dexterity was. VC curled. VC coiled. VC corkscrewed.
VC also generated a stack of photographic data that revealed the probable source of the contortions. At least two remoras scoured across VC's body. VC was probably twisting wildly to escape them.
If the above descriptions of animal behavior resemble human behavior at tax time, I’m just the messenger.
Dr. Weaver studies wild dolphins under federal permit GA1088-1815, National Oceanic and Atmospheric Administration. Contact her at www.dazzlingdolphins.com.
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Article published on Thursday, Nov. 16, 2006
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