River is a boys’ club for dolphins

JACKSONVILLE, Fla. (AP) - The St. Johns River is a boys club for dolphins.

The males boss around the females, form complicated alliances and battle their enemies. It’s a soap opera of sorts, and one that University of North Florida researchers relish.

The river’s roughly 280 adult bottlenose dolphins largely were unstudied before UNF’s coastal biology program started researching the mammals to see how they lived and what made them different from the dolphins that lived off the East Coast, said Quincy Gibson, UNF research scientist.

The year-round research, led by Gibson, includes at least two graduate students and at least 10 undergraduate students each semester. Gibson said she hopes the research will continue indefinitely since there is no stated cap on the study.

The research is funded by several sources: UNF’s Coastal Biology Flagship program, the Elizabeth Ordway Dunn Foundation, the Rotary Club of San Marco, the UNF Environmental Center, and private donations. At least once a week, researchers go out on the water to study these animals.

Now entering their third year of study, researchers are unraveling the mysteries behind the dolphins’ social structures, Gibson said.

Here’s what life is like under the surface of the water:

Dolphins aren’t territorial, so power is all about sex. If they’re high on the social ladder, they’re going to be able to pass along their genes, Gibson said.

Getting up that ladder means beating up their inferiors. Dolphins love to fight, and they need strong buddies to have their back if they are going to avoid getting beaten up day after day.

Jax knows this all too well. The little teenage dolphin would be an easy target, but he teamed up with another dolphin, Duval, who helps keep more aggressive dolphins away.

Jax and Duval are practically inseparable, Gibson said, forming one of the river’s alliances, groups of male dolphins that eat, travel and search for female dolphins together.

These “bro-mances” are common throughout the river and are one of the most important elements of the dolphin social structure.

Alliances scour the river for a female and force her to join their group so one of the dolphins can mate with her. If she tries to swim away, the males will push her back toward the group.

St. Johns River dolphins are fascinating because their small marine society is more complicated than most dolphin groupings, Gibson said.

That is because the alliances sometimes grow, she said. They link with other alliances, forming temporary treaties. With both groups working together, they have a better chance to get some females to join their group.

The dolphins are constantly juggling information about which animals are allies and which ones are their enemies.

Gibson said she saw an all-out dolphin showdown one day on the river.

She said she saw a group of dolphins form two lines facing one another. Then, as if a whistle was blown, they swam toward each other, churning the water.

When they separated, those on one side had sustained more bite marks.

“There was a clear winner and a clear loser,” she said.

Obviously some of the males are succeeding, she said. April is the start of birthing season, and about 10 female dolphins have clear baby bumps.

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Information from: The (Jacksonville) Florida Times-Union, https://www.jacksonville.com