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When we first saw this video, we had no idea what those crazy Japanese divers were looking at. Once the subject of the filming became clear, our eyes could not believe what this porcupine pufferfish was doing. Pictured in the video are two porcupine pufferfish, Diodon holocanthus, one in seemingly great health and the other clearly taking its last few breaths of this life. We wouldn’t go so far as to say that the healthy porcupinefish is comforting the dying one, but to our eyes the healthy Diodon seems to be aware of what is happening to the other one.

Porcupine puffers have been seen schooling, especially as juveniles, but as far as we know they don’t form long term pair bonds and we imagine that the healthy porcupinefish in this video just came across the ailing one. The mechanics of schooling fish and flocking birds are well studied and nowhere in the rules of schooling and flocking does “compassionate” behavior come in. It pulls at our heartstrings to think of what was going through the mind of this healthy porcupinefish as it first got sight of what was happening to the porcupinefish on its side.

Schooling porcupine puffers, image by FlickR user oceanic2007

If the whole point of sexual selection is to pick a healthy mate, then surely almost all animals should be able to discern when one of our kind is in poor health, and especially in critical condition.With its darkened coloration, labored breathing, poor motor coordination and damaged eye it is clear that the larger porcupinefish died some time after this video was made. But why would this healthy porcupinefish stop its daily routine and foraging activities to “accompany” or investigate the dying pufferfish?

While showing no aggression towards the dying pufferfish, in only one instance the healthy porcupine puffer uses its tail to flick a jet of water towards the dying one. Was this an attempt to “wake it up” and alert it to all the diver-predators nearby who could be of harm? We hate to anthropomorphize either of these porcupine pufferfish individuals but we can’t help but think that the dying Diodon felt some comfort in having one of its kind nearby and that the healthy porcupinefish felt some concern for its dying kin. Do you agree or disagree?

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