The eternal tension

Dr. Don Moore, a mammologist, describes his professional career as “having one foot in the zoo world, one foot doing field work.” Which translated in terms of jobs to being associate director of animal care sciences at the Smithsonian National Zoo. 

We met the first time by chance one early morning along Herring Point, he with his two golden labs and I with Mango, a little mighty-mite who fancies himself the meeter-greeter mayor of the beach. 

As we start our walk, I ask him, as I ask others in this series, to describe first impressions. “A beautiful day” is his instant response. Then: a beachscape with no shade, ocean physics in waves and sounds, fewer seabirds than a few years ago … “who knows why – overfishing, climate change, human population.”

And lots of sand, explaining that the ocean floor changes with every storm, forming new sandbars offshore which schools of fish have to swim around, making for variations in species and numbers from day to day.  

Don scans the water for dolphins. 

He recently saw a pod of three dozen spanning a vast stretch of sea, “200 yards north of the jetty and 100 yards south.” Likely a group hunting baitfish in a ball, or following prey such as kingfish or sea trout. In cold months, the fish stay south, partly explaining the absence of dolphins in winter.

“I tell people to look at the size of the fins to determine whether they’re big, medium, or small.” A single dolphin swimming along the shore is likely a male, probably communicating with a group farther out in the water. 

“We know they have cognition, a sense of self, and talk to each other with individualized signals, ‘hey Joe’ … ‘what’s up, Bob?’” he says.

Dolphins you see breaking water, the leapers, are often juveniles displaying happy behavior. Females are less playful, conserving energy. 

What is the essential thing people should know about dolphins?

“They’re a mammal, not a fish. They have hair on their body and they breathe air. The arc of evolution has been from water to semi-water to dry land; dolphins were once land-based. They returned to the water and lost their land legs, which became flippers, but they still ‘walk’ on their tails,” he says.

“The dolphins we see here are Atlantic bottlenose. They have natural sonar, sending sound waves from their mouth that bounce back off objects to the ‘melon’ on their forehead. They can even stun prey with their signals by hovering close to them, like when they prey on rays or skates. They have terrific speed; they’re fast as torpedoes. People know them from Sea World or ‘Flipper’ for their athletic antics, but not how fast or strong they are.”

We keep walking along the wake line, the thin trail of detritus deposited in the sand by surf. 

“Lots of shells in the wake line today,” Don notes, picking one up. Slipper shell, he tells me, pointing out how the inside is divided in half by a partition where the snail lives, resembling a slipper.  “In France, they’re considered delicacies.”  

He finds an oyster shell. “They grow in clusters attached to each other in the wild; they need other shells to grow on.” As with the rings of a tree, each year the oyster’s shell adds another ridge. Some individuals can grow very big. There are four ridges on this one, “about the size we get in restaurants.”

The subject of extinction comes up. Among other consulting gigs, Moore is advisor to Polar Bears International. Are they doomed? “We’ve known about the threat of their extinction from climate change for 30 years,” he says; they used to be fat with lots of cubs, now they’re skinny and have few babies. “There’s still time, but it’s growing short.”

Then, refusing to be a defeatist, he counters with a success story – the comeback of eagles, pelicans and ospreys with the banning of DDT.

With five mass extinctions recorded in the planet’s history, experts agree that number six is well underway. Moore dates it in North America to when humans crossed the Arctic land bridge from Asia 12,000 years ago and began killing buffalo. 

Nature seeks balance. It recalibrates through evolution. In our geological epoch, the Anthropocene, the scales are wildly tilted in Homo sapiens’ favor. “Animals can’t evolve fast enough to cope with people,” says Moore.

Whether there’s hope depends on one’s faith that humans’ better angels will prevail. “Humans as a species are smart enough to develop renewable technology to help us survive as a species. But there is also a Darwinian drive to propagate one’s self.” Selflessness vs. selfishness.  The eternal tension.