Dolphins have been observed, on various occasions, holding pufferfish in their mouths. The terrified fish soon inflate with seawater until they look like a spiky tennis ball, which the dolphins then pass around and toss into the air.
This could be a game – part of the dolphins’ repertoire of naturally playful behaviours – but marine mammal experts aren’t sure what’s going on. Maybe younger dolphins are practising their echolocation skills, finding pufferfish hiding on the seabed and then playing with them like a cat taunts a mouse.
However, it’s clear the dolphins know not to eat the pufferfish, which are full of a deadly chemical called tetrodotoxin. If the marine mammals were planning to eat them, they would eventually tire of playing and tear into their prey. Instead, they hold the pufferfish quite gently in their mouths without crushing them.
Another possible explanation is that dolphins are deliberately getting high on the noxious chemicals that waft out from the pufferfish. Their game may really be an excuse to experience a mild narcotic effect.
Dolphins also have a habit of flinging octopuses. This has a practical benefit of killing the octopus before the dolphin tries to eat it, thus avoiding the danger of being choked by hundreds of suckers clinging to the inside of the dolphin’s throat.
Some animal-on-animal games, however, remain baffling. Orcas are known for their intelligence and playful social behaviours. For a while in the 1980s, an orca pod off Washington state, on the northwest coast of America, started to carry dead salmon around on their heads. The behaviour began with one female and spread to others in the pod.
The trend that had disappeared by 1988, but reemerged in 2024, when dead fish hats once again became the height of orca fashion. Perhaps the orcas are carrying snacks for later, or maybe it’s a game with rules we don’t yet understand.
This article is an answer to the question (asked by Jeannie Holmes, email) 'Do any animals use other animals for sport?'
To submit your questions, email us at questions@sciencefocus.com, or message our Facebook, X, or Instagram pages (don't forget to include your name and location).
Check out our ultimate fun facts page for more mind-blowing science
Read more:
