When a scientific paper begins its list of keywords with “fish cognition”, you know you’re in for a good read.

Culum Brown is tired of people eating fish, and he’s not going to take it anymore. Fish, he says, are smarter than you think. We need to cast off our view of them as dumb slimy creatures and recognize what they can really accomplish.

First, we have to realize that though they may have separated from us evolutionarily more than half a billion years ago, they are not ‘primitive’; it is not as if they stopped evolving. If a fish had stopped evolving could it do this:

That’s right – this bad boy, the cutlips minnow, gathers stones to build a mound to attract mates. And these aren’t the only ‘fishy masons’ (as Brown calls them). The jawfish builds itself a wall in front of its burrow, searching for rocks that fit together like lock and key, leaving only a hole just big enough for them to scurry through. The Rockmover Wrasse builds itself a stone house every night. It also hunts in pairs, one member pushing rocks around so that the other can watch carefully in order to grab any prey that is revealed.

Fish also have sophisticated social intelligence. Take, for instance, the Cleaner Wrasse. They occupy stations – which I’ll generously call a storefront – where other client fish come by to have parasites and dead skin removed by the Cleaner. Brown points out that the fish have the option of several cleaners, so it is important to have a good reputation; should a Cleaner accidentally bite a client, they’ll chase after their fleeing clients and give them a good back rub to make up for it. They also prioritize certain customers over others. Model that, economists.

Many other fish can recognize multiple individuals, and can count the number of fish in a group at a glance.

Some fish also use tools: a number of species use rocks to break open shellfish, or glue their eggs to leaves that they can them drag around as they go about their errands.

I actually came away impressed from this paper; I hadn’t known most of these fishy facts. Yet despite how smart fish are, people will still eat them; after all, they’re pretty okay eating piggies (they’re pretty smart). What matters more than any kind of intellectual empathy is a anthropomorphic one. After all, which would be more okay to eat: a really dumb monkey or a really smart (but ugly) fish?

(My biggest take-away from this is not to eat a Wrasse; those guys are pretty smart, and have a much larger brain for their size than you’d expect.)

via Marginal Revolution

Update: Ed Yong happened write an article today on this very subject! Lionfish are strategic, social hunters:

During night dives, Lönnstedt often saw teams of two to four lionfish positioning themselves around schools of smaller fish and using their fan-like pectoral fins to corral their prey “like fishermen with their nets”. The hunters then take turns to dart into the school of prey, picking them off one at a time… “Fish social behaviour is much more complex than previously assumed. Moving away from a stimulus of major interest—prey—in order to actively recruit a partner that is initially out of sight suggests planning and awareness of objects that [they can’t see].”…But in these pursuits, the two partners are merely hunting next to each other and relying on their complementary abilities. The lionfish are doing something more impressive: they’re working together to corral their prey and taking turns to go in for the kill.

Reference

Brown C (2014). Fish intelligence, sentience and ethics. Animal cognition PMID: 24942105