Eight-month-old bottlenose dolphin Vidalia had been entangled by discarded fishing line for half his life. Since his November rescue and release, however, he’s so busy making up for lost time that the photographer couldn’t even get a recent decent picture of him. While he races around invisibly, his mom Valiant slid down a modest mound as a dolphin dipped into green glass.
The mother dolphin Valiant was either teasing or testy with her son Vidalia last Sunday. I wasn’t sure which. Maternal irritation is rare to see at sea. I don’t claim to know when wild dolphins are teasing each other. But their subsequent behavior says she wasn’t testy.
The mother dolphin had just surfaced when her yearling son Vidalia bopped out of the water next to her. Maybe he accidentally struck her. Maybe his ceaseless activity ran into one of those invisible walls by which baby animals from monkeys to elephants learn the limits of behavior in their society. Maybe mother decided to bop her baby playfully.
What she did was arch over the surface and deliberately plunge down on her calf, sinking them both into the invisible depths.
That let off steam, albeit temporarily. Side-by-side, mother and son meandered north from one bay to the next. En route, mother picked up an orange leaf in her mouth and carried it briefly; I recalled the time she carried a hapless flounder the same way through crystalline turquoise waters (Dolphin Watch’s Playing with your food).
As mom flirted with the leaf, calf Vidalia pitched and presented his belly to her. In dolphin terms, this is an invitation to interact, kind of like a human smile. I don’t know if mother “smiled” back but she released the orange leaf, which floated away. Vidalia ducked underneath her and nursed.
That revved his engines again. While his mother stayed their course, he zipped around her in large circles like a wild horse galloping along the fence line of a big corral to avoid the person standing in the middle of it, except that his circles were shaped more like blobs rising in a Lava Lamp. He was in the “speed stage” of bottlenose dolphin calf development, a stage where calves appear to be testing their powers of acceleration.
Vidalia will be a year old next month. Developmentally speaking, his “speed stage” of zooming and zipping around the seas was several months late.
Had entanglement in fishing line cut into his normal infant development as well as his tender dolphin skin?
After becoming entangled in his fifth month of life, Vidalia spent his time mainly gyrating to try to free himself from his fishing line body noose.
We didn’t see him do the things that kid dolphins his age do. We never him repeat a behavior as if practicing it (like tailslapping or pushing himself vertically out of the water in a spyhop). We never him saw play with other calves.
We never saw him experiment with play-feeding behavior called snagging. Snagging involves following tiny fish close enough to pelt them with childish blasts of echolocation to test its stunning power. He may have snagged a fish successfully and even tasted it tentatively. But like a bit in a horse’s mouth, the “bit” of fishing line drawn across the back of his throat would have blocked any fish he tried to swallow and presumably made nursing more palatable.
We stopped so that Capt. John Heidemann could haul a massive waterlogged plank onto our boat; any boat that hit it would be seriously damaged. That took a while, during which a passing boat provided more diversion. Mom Valiant slid down the wake that spread out perpendicularly as the boat passed, flowing suspended down its face like a dolphin dipped into green glass. Then she resumed her trek into the next bay, Vidalia dashing around nearby.
When we caught up to them, Vidalia had caught up to her and was repeating his bids to nurse. These involved swimming upside down under his mom, revealed by his little white belly gleaming up through green seas like milk spilt a foot below the surface. Although year-old bottlenose dolphin calves still nurse, it’s rare to see this so bluntly.
When he surfaced, he clambered onto her back the way he did when he was entangled in fishing line and potentially exhausted from trying to free himself of it. I was stunned. Clambering is extremely rare.
At this point, clambering was presumably unnecessary. Had he learned to connect it with nursing?
If so, might clambering be something animal behaviorists call “superstitious” behavior? Animals (and people) tend to develop superstitious behavior when they’ve been shocked by something and repeat their shaken response in the absence of the frightening stimulus. A horse that shies from a bird suddenly flushing out of the foliage along a bridle path may continue to shy at that spot though the startling bird is no longer there. Shying (pointlessly) is the superstitious behavior.
I’ve only seen clambering one other time: by big bull Twin Dip (Dolphin Watch’s An ungodly glow). Intriguingly, he’s the bull most likely to be Vidalia’s father.
It was understandable if Vidalia showed some developmental delays. When you’re busy fighting that which binds you, you can’t work on much else.
Ah, but that was yesterday and this was today. He’s free now.
At the end of our observation last Sunday, the distance between Vidalia and his mom was somewhere between the length of a basketball court and a football field, which is developmentally advanced for a calf his age. I’m betting he catches up just fine.
Dr. Weaver studies wild dolphins under federal permit 16299, National Oceanic and Atmospheric Administration. Send her an email at email@example.com or visit her website www.dolphinsuperstore.com. Read her Dolphin Watch column weekly at www.TBNweekly.com. NOAA advises anyone who sees a stranded dolphin in the Gulf of Mexico to call 877-942-5343 or 877-433-8299.