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Sea Note 2: Dolphin Death at Sea~Pain and Precision
Field Day 3 July 2020
Picture Caption. Lana,
a mother bottlenose dolphin, nudges the bobbing corpse of her dead newborn son
with her chin, initially pushing it along. With time, her efforts to rouse his indifferent
body grew stronger.
We need the dark to know the day. A recent survey of our dolphin study area presented Capt. John and I, who monitor free-ranging bottlenose dolphins under federal permit, with one of the somber sides of dolphin field work: a mother dolphin tending the corpse of her newborn baby boy. His tiny corpse floated on the water surface, so young when death called that his dorsal fin had not yet stiffened. His mother’s year-long investment in pregnancy was wasted.
The mom was Lana, a dolphin we have known since the start of our study. That means she is at least 28 years old in a lifetime that could last 50 years or more. As of this writing, we have seen her 391 times.
Lana’s futile attempts to rouse her dead baby mainly involved nudging it with her chin. Initially, her efforts served to push the indifferent body along. As her efforts grew stronger, her nudging rolled it along. Her later efforts, stronger still, sometimes propelled it into a stiff headstand or, propped on her head, out of the water.
Death provokes many responses. The pain it provokes is understandable. We watched Lana and her futile attempts with pain. Part of my pain came from just being human.
Part of my pain came from my training. I pursued an education in developmental psychobiology in my fascination with the process of growing up and admiration that most of us make it to adulthood reasonably unscathed despite the jolts of childhood.
Part of my pain came from death visiting this particular dolphin. In human terms, Lana would be described as a gentle soul because she is receptive and compliant with others, including our research boat. She also develops skin conditions from time to time, which makes me wonder if there are nervous dolphins out there.
Mourning mother dolphins are typically alone. They shield the corpse from harm in death as they do the calf in life, doing their best to keep onlookers at bay. To avoid distressing her further, Capt. John kept our boat 3-4 boats length away (60-80 feet or 18-24 meters).
If one is unfamiliar with dead baby dolphins at sea, a condition I recommend, the small corpses are hard to recognize as such. The little body bobs on the surface, its round white belly gleaming against green sea water and its mother’s gray face. If anything, they look like a white plastic bag puffed with air to casual observers rushing past on jet skis and boats. Most people never see them, which is well because they unintentionally leave the mourning mother alone with her futile attempts.
All of the jet skis and boats zipped past Lana that day, save one man on a jet ski who slowed and approached cautiously. Lana held her face against the corpse of her newborn floating at her side, its white belly facing the sky and tiny dark tail fin or fluke flapping lifelessly against the water. Her eye wide, Lana watched the man approaching on the jet ski for a moment and then shoved the corpse underwater with a mighty heave.
Pain is understandable, but how does death provoke precision? From skepticism, the heart of science.
Science is based on statistics. Statistics depend on data points. One needs a certain number of data points to trust the message that they bring. My scientific training at Emory University was to see a rare animal behavior at least five times before I should trust that it was real, that is, typical of the species rather than a mere idiosyncrasy of an individual. Though infrequent, rare events in animal behavior are important to study. Rare events are often mighty moments that help us better understand both the individual who sustains the blow and the psychology of the species capable of sustaining blows, such as a broken heart. Five observations of the “rare but significant event” are the bare-bones minimum for precision.
The problem is that a rare event is infrequent. It may not occur five times. Once may be quite enough! As undoubtedly happens at sea, it may occur many times without witnesses. For me, the question became how much to trust my impressions of the rare but significant events I witnessed at sea, like mourning mother behavior.
I watched the first four mourning mothers I saw at sea with what I hoped was scientific distance and dispassion. The futile attempts of a mourning mother to rouse the indifferent corpse of her baby are very similar across females. Dolphin mothers prod the corpse of their dead newborn with single-minded focus for hours or days. Their efforts become frenzied. Some moms prod it until the skin on her head is deeply abraded. They eat rarely or not at all. It is as if each mother is doomed to repeat that first vital maternal response following a birth: prodding the flummoxed newborn to help it reach the water surface and its first breath of air.
This set of behaviors only occurs in the presence of her baby’s corpse and is difficult to observe with dispassion. Memories remain vivid. One example was that Lana was 50 yards (45 m) away when we first saw her, a substantial distance in pitching seas. Yet I glimpsed the white object at her side and winced to realize that I knew immediately that it was a dead baby.
I have now seen twice the requisite minimum of mourning moms at sea. Lana was the 8th. It has taken 16 years, a long time that simultaneously shows that calf survival along the “Enchanted River” is high (estimated at 70% of 156 births) and witnessing mourning mother behavior is rare (estimated at 5%).
I do not when, but I crossed over. I now trust the evidence of my senses that bottlenose dolphins have their own sense of death. Though I can never know precisely what Lana felt as a mourning mom, I know she felt bad.
Lana and her unmoved baby flowed east on the flood tide. Their story may appear to be more about my pain than Lana’s pain. Maybe the words of the story emerged as they did because our own human pain is easier to ponder because we can at least think through it. I wonder: Can Lana?
Follow-up Facts
·In the case of mourning mother behavior, science came to the rescue. Enough marine mammalogists scattered across the world have now seen these rare but significant events for science to declare that it is real, that is, typical of the species rather than the occasional individual idiosyncrasy.
·Dead marine mammals are collected and necropsied to determine cause of death. However, stranding personnel do not take a bobbing corpse away from its mother to avoid distressing her further. Only abandoned corpses are necropsied. Abandonment appears to be rare because very little is known about why most baby dolphins die.
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