Quick Answers: Do Fish Feel Pain?

Q: Can fish feel pain?
Russell, Elma, New York, USA

A: Perhaps so. Recent findings from Scotland indicate some can. Investigators (from Roslin Institute and the University of Edinburgh led by biologist Lynne Sneddon now at Liverpool University) used a variety of approaches, but the clincher was behavior. After the team injected simulated bee venom (a chemical extract) into the lips of rainbow trout, the trout indicated pain by:

- rocking with pain, much as mammals do

- rubbing their lips on the gravel floor of the tank and on tank walls

- taking three times longer than the control fish to resume eating after being 'stung' by the 'bees.'

Further Reading:

Fish feel pain, BBC

Q: What does an octopus do when a predator threatens it?
Brittany, Orange, New South Wales, Australia

A: It depends on the octopus. The extremely toxic blue-ringed octopus displays his brilliant blue rings to warn a predator off.

"Many octopus have a pair of 'eye spots' that they can flash", says biologist Roy Caldwell. This may startle predators just as the eyespots on a moth do.

Most octopuses release a reservoir of dark inky dye, which might serve as a smoke screen and/or be noxious disabling the predators chemosensory organs. Other species can release ink mixed with mucus. This forms a brown or black glob that hangs in the water and looks somewhat like the octopus. Often, as the octopus releases the deceptive glob, it changes color (usually to white) and gets away. The predator attacks the glob and gets nothing more than a mouth full of bad tasting ink.

Octopuses also can change their skin coloration to go unnoticed.

Several octopus species drop their arms off their body when attacked. "The wiggling autotomized arms will even lock onto the predator with its suckers," says Caldwell. "This is usually sufficiently distracting to allow the octopus to escape." Re-growing lost arms is a snap for an octopus.

(Answered May 12, 2008)