Catfish, comprising the group Siluriformes, are a diverse group of ray-finned fishes that can be found on every continent except for Antarctica. These fish are distinguished by the presence of barbels on their snout, which they use to detect prey and navigate in low-light environments. In challenging conditions, these fish must be flexible and able to adapt their behavior to survive. This article explores some of the behavioral adaptations of catfish and asks the question: are catfish smart?
Social Intelligence
Catfish are capable of learning the characteristics of individual fish, particularly in relation to their success in fights – this is a useful strategy as it enables individuals to avoid those which they are unlikely to succeed against in an altercation. Yellow bullheads have been found to show fearful reactions when exposed to the scent of dominant fish they have encountered previously, showing that this species is capable of remembering conspecifics.
Some species of catfish perform parental care duties; for example, the male kampango, Bagrus meridionalis, tends its broods and carries invertebrate prey to the nest. This could be an example of social learning, as the young gain information through this interaction.
The brown bullhead, Ictalurus nebulosus, has been shown to be able to identify other conspecifics and determine what food they have consumed, using food-derived amino acids in their urine. This can lead to the fish being able to recognize the source of the food, meaning that this may be another example of social learning in this group of animals. A study examining the olfactory perception (by which amino acids can be detected) in channel catfish (Ictalurus punctatus) found that associations are learned rather than being innate, providing further evidence of this species’ intelligence.
Recognition of members of the same species is important for forming groups, too. Juvenile striped catfish, Plotosus lineatus, school soon after hatching, and recognize each other using chemical signals. This is a social strategy that reduces the risk of predation.
Problem-Solving
Catfish are bottom-dwelling fish that often forage and hunt in low-light conditions. Research has found that European catfish, Silurus glanis, can track prey by following the hydrodynamic alterations they leave in their wake. They detect the movement using their lateral line and may also pick up on chemical cues left by the prey animal. This is definitely a smart strategy, as the prey are less likely to notice the predator when it approaches from behind.
Tool use has also been reported in catfish: the hoplo catfish, Megalechis thoracata, lays its eggs on leaves and uses these to carry them to safety if there is a threat. This is an extraordinary behavior that may be indicative of greater cognition in this species.
Another scenario in which the ability to make decisions is essential is in the presence of predators. A study involving channel catfish, Ictalurus punctatus, found that juveniles feed less and exhibit lower levels of movement when a predator such as a largemouth bass is present. While this shows that individuals can respond to the environment around them, this is not unusual, and many animals will reduce activity levels when there is a threat. Thus, this feature alone does not necessarily imply that catfish are smart.
Conclusions – Are Catfish Smart?
Catfish perform a wide variety of behaviors, some of which are associated with higher levels of intelligence in animals – for example, the use of tools and the ability to learn socially. This suggests that catfish are indeed smart, utilizing what they have in order to thrive in many environments across the world.
