Dolphin Watch
Barging in and out
By ANN WEAVER
| Article published on Thursday, Sept. 20, 2007 |
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![[Image]](/content_images/092007_out-01.jpg) |
| Photo by ANN WEAVER |
| Bottlenose dolphins fight by punching each other with their tailstocks or peduncles, behavior called tailwhips. |
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Six bottlenose dolphins idled up a narrow channel. Suddenly, the water hurled sideways as they thumped each other with wild peduncle punches called tailwhips. A fight had broken out.
Two brawny bulls exploded out of the group. Burly bull Edge arched over the water like the letter C fallen on its face. You couldn’t miss him.
But to guarantee it, he coughed out a mighty chuff, a vocalization that said he was extremely aroused. Then he slammed his bulk back down into the water. Lurching waters punctuated his display.
Five feet away and split seconds later, hefty pal KK arched, chuffed and slammed back down exactly like Edge. Then, in just four feet of water, they vanished.
The arching, chuffing and slamming was a bottlenose bull threat display, incredible for several reasons.
Its suddenness and vigor made it conspicuous. But displays exist to communicate clearly and instantly. Displays symbolize an idea. They’re behavioral abbreviations.
Countless species display. Consider a man clenching his fist. He’s using a human threat display. The fist gets your attention. It instantly communicates aggressive intent.
Its what happens afterwards that makes a gesture a display. If the clenched fist is followed by a punch, it isn’t a display. It’s a prelude. After all, you need a fist to throw a punch.
A display is when you imply a behavior without following through. A man who clenches his fist at you isn’t ready to fight. (If he was, he’d punch you directly). But he implies what he’s thinking.
It’s healthy not to bottle up emotions. It’s unhealthy to express some of them. So displays abound. They’re psychological warfare.
The bulls’ threat display was incredibly efficient. It commanded attention, advertised, communicated, intimidated and minimized the risk of counterattack. Dolphins have excellent memory. Today’s dolphins would remember Edge and KK’s message: Watch out. We’re tough. We’ll be back.
This happened during a Labor Day gathering of bottlenose dolphins around the most northern of three islands. Before causeway construction began, the reason for our study, the dolphins would’ve assembled around the southern island. But a giant construction barge was parked there for months. Although it came and went, it was mostly there. When it was, the dolphins weren’t.
The threat was not idle. The ransacked group included bulls and females to fight over. In the slender channel just 6-feet deep, females JJ and Rim and bulls Cheetah and LA Cheetah swam past foraging shorebirds who startled and stared at them. Probable bulls Brick and Square Scoop appeared and trailed them.
Suddenly Cheetah spun around and launched himself with the exaggerated ‘humping’ swim that captive dolphins use when fighting. That’s when the water exploded with those staggering peduncle punches.
We don’t know who did the punching. The chaos of aquatic conflict obliterated the details. Six bulls meant plenty of possibilities. Maybe all three pairs tangled. Maybe it was four against two: Cheetah and LA Cheetah allied with Brick and Square Scoop against Edge and KK. Maybe Cheetah fought off Edge and KK alone.
The fight was short so there was probably an imbalance of power. Only evenly matched rivals fight for long. Cheetah and LA Cheetah resumed their idle swim with JJ and Rim.
Edge and KK lost this round, relegated to the thundering threat display that hinted at the complexity of bottlenose bull rivalries.
Finally, Edge and KK’s incredible display meant dolphins use threat displays like more observable animals.
The bull’s dramatic display was like the day Vernon, a muscular male bonobo ( pygmy chimp Pan paniscus), ran screaming past females who’d been ignoring him at the San Diego Wild Animal Park. Thrashing a big branch as he ran, he vented frustration without drawing female fire
Male common chimpanzees (Pan troglodytes) also thunder through throngs of other chimps. They enhance their threats by screaming, throwing, or dragging things like the displaying male who ran through Jane Goodall’s camp trouncing a metal bucket.
In captivity, zoo bedrooms are havens from the staring public. Captive silverback gorillas (Gorilla sp.) may rush at strangers to these hallowed halls, pounding convenient metal doors to be more intimidating. You must stand steady, trusting the bars that separate you from 375+ pounds of ferocity. If you cringe, the gorilla will remember and bully you thereafter. But then, that’s the point. Threat displays reveal whom you can intimidate.
Free-ranging gorilla males display at the edge of gorilla groups for additional reasons. Fierce roars, chest pounding and foliage trashing are to intimidate males but also entice females to join them and start a new harem.
Who hasn’t seen similar human male displays?
I saw my first threat display as a young USDA Inspector. As we entered Lincoln Park Zoo’s chimp bedroom area, a chimp leapt to the water drinker and then shot across the enclosure. The keeper shoved me over to protect me from the chimp’s intended shower of spit and (good measure of troglodyte) vinegar.
At sea, bottlenose dolphins rush at human swimmers to threaten them. If it’s a display, they’ll veer off at the last second. If its not, intimidation by a 500-plus pound torpedo with attitude is the least of your worries. It’s illegal to swim with wild dolphins for good reason.
Remember, you only know later if a gesture is a display. Knowing Edge, we were lucky to see this dramatic display from the safety of our boat. Why can’t humans just use psychological warfare?
Related Stories
A Particular Proximity, Attack of the Oyster, The Brass Ring, Carrying on with Coastal Keep Away, Fish Frisbee, Food Court, Out of the Blue, Where Whitley Went Down, Whipped into Shape
Dr. Weaver studies wild dolphins under federal permit GA1088-1815, National Oceanic and Atmospheric Administration. Send her an e-mail at acweaver@tampabay.rr.com or visit www.dazzlingdolphins.com.
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Article published on Thursday, Sept. 20, 2007
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