As Borras-Chavez and Sperou watched Nora guard her lifeless pup, they felt mixed emotions. "It's being a scientist and a researcher and realizing that this is such a fascinating thing going on, and our curiosity just sparks," Sperou said. "And then there's the flip side of it, where it's like we are humans, and we are seeing a mother carrying around her dead baby." Or, as Borras-Chavez put it, "you weep a little bit." The researchers abstained from flying drones or sampling the seals when they were with pups, dead or alive. "Our model is usually science-first," Borras-Chavez said. "But if an action that we're taking would have been disrespectful for us, if somebody else would do it, then we don't do it."

When Nora eventually abandoned her pup in 2023, the researchers retrieved it for a necropsy. The pup was female, and her teeth had just begun to poke out from her gums. Her stomach was empty, suggesting she had not been suckling and likely died of emaciation. Many of her bones had been crushed but only after her death, likely when her mother lay on top of her small body. The researchers called the pup Rafaella, after the lagoon.

It's not clear why no leopard pups seem to survive in Chile. An unpublished genetic analysis on Rafaella ruled out inbreeding as a cause of death. More generally, the researchers suspect the conditions of the lagoon, while peaceful and predator-free for adult seals, are less than ideal nurseries, given that the lagoon's ice floes break apart in a matter of days. One of the researchers' hypotheses is "that they're having their pups on these small icebergs, and the icebergs are breaking or melting, and the pups fall into the water and will instantly drown and freeze," Sperou said. Besides, the lagoon itself is no forever home for the seals, as the glacier will continue to recede until it vanishes entirely.

The obvious question underlying this research—why a leopard seal would spend days lugging around the 150-pound body of a pup that has died—is impossible to answer, at least for now. Sperou suspects the response is largely physiological. Whenever a mammalian mother—human, seal, or otherwise—has a baby, their body flushes with serotonin, dopamine, and oxytocin. These hormones help bond the mother to her baby. "It's out of her control," Sperou said. "It's her hormones and her body telling her to stay with her pup."

Scientists are often resistant to call behavior like this "grief" to avoid accusations of anthropomorphism, the act of interpreting animal behavior through human terms. Borras-Chavez offered "after-death caregiving" as a friendlier alternative than "post-mortem attentive behavior." As Sperou makes clear, "Do we know if she's actually grieving? No, we don't." But, she added, "I think it's understandable to say this could be some type of grieving behavior"—emphasis on the could.